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CESSNA 172 TRAINING MANUAL
CESSNA 172
TRAINING MANUAL
by
Oleg Roud
and
Danielle Bruckert
Published by Red Sky Ventures, Memel CATS
Copyright © 2006
by O. Roud & D. Bruckert © 2006, This Edition 2014
Page 1
CESSNA 172 TRAINING MANUAL
Contact the Authors:
We appreciate your feedback.
D Bruckert
O Roud
[email protected]
[email protected]
PO Box 11288 Windhoek, Namibia
PO Box 30421 Windhoek, Namibia
Red Sky Ventures
Memel CATS
CreateSpace Paperback: ISBN-13: 978-1463675448; ISBN-10: 1463675445
Lulu Paperback: ISBN 978-0-557-01472-9
First Published RSV/Memel CATS © 2006
This 3rd Edition RSV/Memel CATS © 2014
More information about these books and online orders available at:
http://www.redskyventures.org
Other aircraft presently available in the Cessna Training Manual series are:
Cessna 152, Cessna 172, Cessna 182, Cessna 206.
COPYRIGHT & DISCLAIMER
All rights reserved. No part of this manual may be reproduced for commercial
use in any form or by any means without the prior written permission of the
authors.
This Training Manual is intended to supplement information you receive from
your flight instructor during your type conversion training. It should be used for
training and reference use only, and is not part of the Civil Aviation Authority or
FAA approved Aircraft Operating Manual or Pilot's Operating Handbook. While
every effort has been made to ensure completeness and accuracy, should any
conflict arise between this training manual and other operating handbooks, the
approved aircraft flight manuals or pilot's operating handbook should be used as
final reference. Information in this document is subject to change without notice
and does not represent a commitment on the part of the authors, nor is it a
complete and accurate specification of this product. The authors cannot accept
responsibility of any kind from the use of this material.
ACKNOWLEDGEMENTS:
Peter Hartmann, Aviation Center, Windhoek: Supply of technical information,
maintenance manuals and CD's for authors research
Brenda Whittaker, Auckland New Zealand: Editor, Non Technical
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
Table of Contents
Introduction............................................................................................................................................. 5
History................................................................................................................................................ 5
Development of the C172...................................................................................................................5
Terminology ......................................................................................................................................... 7
Useful Factors and Formulas.................................................................................................................10
Conversion Factors........................................................................................................................... 10
Formulas........................................................................................................................................... 11
Pilot's Operating Handbook Information...............................................................................................11
AIRCRAFT TECHNICAL INFORMATION....................................................................................... 13
Models and Differences ................................................................................................................... 14
Type Variants.................................................................................................................................... 20
Airframe................................................................................................................................................ 23
Doors ............................................................................................................................................... 24
Flight Controls.......................................................................................................................................27
Elevator.............................................................................................................................................27
Rudder.............................................................................................................................................. 28
Ailerons............................................................................................................................................ 28
Trim ................................................................................................................................................. 30
Flaps..................................................................................................................................................33
Landing Gear......................................................................................................................................... 38
Shock Absorption............................................................................................................................. 38
Hydraulic System-Retractable Landing Gear (C172RG Only)....................................................... 39
Brakes............................................................................................................................................... 43
Towing.............................................................................................................................................. 44
Engine and Propeller............................................................................................................................. 46
Engine Controls................................................................................................................................ 49
Constant Speed Propellers (C172RG, R172/FR172)....................................................................... 51
Engine Gauges.................................................................................................................................. 53
Induction System and Carb. Heat..................................................................................................... 55
Fuel Injection System (R172/FR172, C172R, C172S).....................................................................57
Ignition System ................................................................................................................................58
Engine Lubrication........................................................................................................................... 61
Cooling System.................................................................................................................................63
Fuel System........................................................................................................................................... 66
Standard Fuel System Schematic .................................................................................................... 67
Fuel System Schematic C172RG..................................................................................................... 68
Fuel System Schematic Fuel Injected Models .................................................................................69
Fuel Measuring and Indication......................................................................................................... 73
Fuel Venting......................................................................................................................................74
Fuel Drains....................................................................................................................................... 75
Priming System ................................................................................................................................76
Auxiliary Fuel Pump ....................................................................................................................... 77
Electrical System................................................................................................................................... 78
Battery.............................................................................................................................................. 78
Electrical Power Supply................................................................................................................... 80
Electrical Equipment........................................................................................................................ 80
System Protection and Distribution.................................................................................................. 81
Electrical System Schematic Conventional Aircraft........................................................................ 84
G1000 Electrical Distribution Schematic......................................................................................... 85
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CESSNA 172 TRAINING MANUAL
Flight Instruments and Associated Systems ......................................................................................... 86
Ancillary Systems and Equipment................................................................................................... 91
Avionics Equipment..........................................................................................................................93
FLIGHT OPERATIONS....................................................................................................................... 98
PRE-FLIGHT CHECK .........................................................................................................................98
Cabin.................................................................................................................................................99
Exterior Inspection......................................................................................................................... 100
Passenger Brief............................................................................................................................... 105
NORMAL OPERATIONS.................................................................................................................. 106
Starting and Warm-up..................................................................................................................... 106
After Start....................................................................................................................................... 109
Takeoff............................................................................................................................................ 114
Climb.............................................................................................................................................. 122
Cruise..............................................................................................................................................123
Mixture Setting............................................................................................................................... 124
Descent, Approach and Landing ....................................................................................................127
Balked Landing (Go Round) Procedure......................................................................................... 131
After Landing Checks.....................................................................................................................132
Taxi and Shutdown......................................................................................................................... 132
Circuit Pattern.................................................................................................................................133
Circuit Profile................................................................................................................................. 139
Circuit Profile – Normal Circuit..................................................................................................... 140
Circuit Profile – Maximum Performance Circuit........................................................................... 140
Note on Checks and Checklists...................................................................................................... 141
ABNORMAL AND EMERGENCY PROCEDURES........................................................................ 143
Emergency During Takeoff ............................................................................................................143
Gliding and Forced Landing...........................................................................................................145
Engine Fire..................................................................................................................................... 147
Electrical Fire................................................................................................................................. 148
Rough Running Engine.................................................................................................................. 148
Magneto Faults............................................................................................................................... 148
Spark Plug Faults............................................................................................................................149
Abnormal Oil Pressure or Temperature.......................................................................................... 149
Carburettor Ice................................................................................................................................ 150
Stalling and Spinning......................................................................................................................151
Fuel Injection Faults....................................................................................................................... 151
Landing Gear Emergencies (RG model)........................................................................................ 152
PERFORMANCE .............................................................................................................................. 155
Specifications and Limitations....................................................................................................... 155
Ground Planning ............................................................................................................................156
REVIEW QUESTIONS...................................................................................................................... 168
NAVIGATION AND PERFORMANCE WORKSHEETS................................................................173
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
Introduction
This training manual provides a technical and operational description for most
models of the Cessna 172 series aeroplane, from the C172 and C172A to the
C172SP, and includes systems descriptions for common variants, including the
C172RG, P172D, and R172/FR172.
The information is intended for ground reference and as an instructional aid to
assist with practical training for type transition or ab-initio training, provided by
an approved training organisation.
The book is laid out according to a typical training syllabus progression for ease
of use. This material does not supersede, nor is it meant to substitute any of the
manufacturer’s operation manuals. The material presented has been prepared
from the information provided in the pilots operating handbook for the model
series, Cessna maintenance manuals and from operational experience.
History
The Cessna aircraft company has a long and rich history. Founder Clyde Cessna
built his first aeroplane in 1911, and taught himself to fly it! He went on to build
a number of innovative aeroplanes, including several race and award winning
designs. The Cessna Aircraft company was formally established by Clyde in
1927, in the state of Kansas.
In 1934, Clyde's nephew, Dwane Wallace, fresh out of college, took over as head
of the company. During the depression years Dwane acted as everything from
floor sweeper to CEO, even personally flying company planes in air races
(several of which he won!). Under Wallace's leadership, the Cessna Aircraft
Company eventually became the most successful general aviation company of
all time.
Cessna first began production of two-seat light planes in 1946 with the model
120 which had an all aluminium fuselage and fabric covered wings. This was
followed by a nearly identical model the 140, with aluminium clad wings. More
than 7,000 model 120-140's were sold over four years when Cessna stopped
production in order to focus on four-seat aircraft.
At the time of publication, Cessna continues to produce a range of aircraft, from
their signature piston engine range, largely unchanged since first appearance, to
the PT6 turbine powered Caravans, and the Citation Jet.
Development of the C172
The Cessna 172 is probably the most popular flight training aircraft in the world.
The aircraft made her first flight in November 1955, the first production models
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CESSNA 172 TRAINING MANUAL
were delivered in 1957, and became an overnight sales success and over 1400
aircraft were built in its first full year of production. It is still in production in
2005, more than 35 000 have been built.
The Cessna 172 started as a relatively simple tricycle undercarriage
development of the tail-dragger Cessna 170B. The airframe was basically a
170B, including the “fastback” or colloquially called the straight-back fuselage
and effective 40º Fowler flaps. The maximum gross weight was identical
although the useful load went down 45 pounds.
Later versions incorporated a swept back tail, revised landing gear, a lowered
rear deck, and an aft window. Cessna advertised this added rear visibility as
“Omni-vision”.
The airframe has remained almost unchanged since then, with updates mainly
affecting avionics and engine fittings, including the most recent the Garmin
1000 glass cockpit option. Production ended in the mid-1980s, but was resumed
in 1996 and
continues at the time of writing.
In 1966 Cessna began assembly of US airframes at Reims Aviation in France.
The Cessna F172 was built by Reims Cessna through to 1971. Cessna also
produced a retractable version and most models are available as a seaplane
version with floats.
Illustration 1a Cessna 172
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CESSNA 172 TRAINING MANUAL
Terminology
Airspeed
KIAS
Knots Indicated
Airspeed
Speed in knots as indicated on the airspeed
indicator.
KCAS
Knots Calibrated KIAS corrected for instrument error. Note this error
Airspeed
is often negligible and CAS may be omitted from
calculations.
KTAS
Knots True
Airspeed
KCAS corrected for density (altitude and
temperature) error.
Va
Max
Manoeuvering
Speed
The maximum speed for full or abrupt control
inputs.
Vfe
Maximum Flap
The highest speed permitted with flap extended.
Extended Speed Indicated by the top of the white arc.
Vno
Maximum
Structural
Cruising Speed
Sometimes referred to as “normal operating
range”. Should not be exceeded except in smooth
conditions and only with caution. Indicated by the
green arc.
Vne
Never Exceed
speed
Maximum speed permitted, exceeding will cause
structural damage. Indicated by the upper red line.
Vs
Stall Speed
The minimum speed before loss of control in the
normal cruise configuration. Indicated by the
bottom of the green arc. Sometimes referred to as
minimum ‘steady flight’ speed.
Vso
Stall Speed
Landing
Configuration
The minimum speed before loss of control in the
landing configuration, at the most forward C of G*.
Indicated by the bottom of the white arc.
*forward centre of gravity gives a higher stall speed and so is used for certification
Vx
Best Angle of
Climb Speed
The speed which results in the maximum gain in
altitude for a given horizontal distance.
Vy
Best Rate of
Climb Speed
The speed which results in the maximum gain in
altitude for a given time, indicated by the
maximum rate of climb for the conditions on the
VSI.
Vref
Reference Speed The minimum safe approach speed, calculated as
1.3 x Vso.
Vbug
Nominated
Speed
The speed nominated as indicated by the speed
bug, for approach this is Vref plus a safety margin
for conditions.
Vr
Rotation Speed
The speed which rotation should be initiated.
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CESSNA 172 TRAINING MANUAL
Vat
Barrier Speed
The speed to maintain at the 50ft barrier or on
reaching 50ft above the runway.
Maximum
Demonstrated
Crosswind
The maximum demonstrated crosswind during
testing.
Meteorological Terms
OAT
Outside Air
Temperature
Free outside air temperature, or indicated outside air
temperature corrected for gauge, position and ram
air errors.
IOAT
Indicated
Outside Air
Temperature
Temperature indicated on the outside air
temperature gauge.
ISA
International
Standard
Atmosphere
The ICAO international atmosphere, as defined in
document 7488. Approximate conditions are a sea
level temperature of 15 degrees with a lapse rate of
1.98 degrees per 1000ft, and a sea level pressure of
1013mb with a lapse rate of 1mb per 30ft.
Standard
Temperature
The temperature in the International Standard
atmosphere for the associated level, and is 15
degrees Celsius at sea level decreased by two
degrees every 1000ft.
Pressure
Altitude
The altitude in the International Standard
Atmosphere with a sea level pressure of 1013 and a
standard reduction of 1mb per 30ft. Pressure Altitude
would be observed with the altimeter subscale set to
1013.
Density
Altitude
The altitude that the prevailing density would occur
in the International Standard Atmosphere, and can
be found by correcting Pressure Altitude for
temperature deviations.
Engine Terms
BHP
Brake Horse
Power
The power developed by the engine (actual power
available will have some transmission losses).
RPM
Revolutions
per Minute
Engine drive and propeller speed.
Static RPM
The maximum RPM obtained during stationery full
throttle operation
Weight* and Balance Terms
Moment Arm
The horizontal distance in inches from reference
datum line to the centre of gravity of the item
concerned, or from the datum to the item 'station'.
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CESSNA 172 TRAINING MANUAL
C of G
Centre of
Gravity
The point about which an aeroplane would balance if
it were possible to suspend it at that point. It is the
mass centre of the aeroplane, or the theoretical point
at which entire weight of the aeroplane is assumed
to be concentrated. It may be expressed in percent
of MAC (mean aerodynamic chord) or in inches from
the reference datum.
Centre of
Gravity Limit
The specified forward and aft points beyond which
the CG must not be located. Typically, the forward
limit primarily effects the controllability of aircraft
and aft limits stability of the aircraft.
Datum
(reference
datum)
An imaginary vertical plane or line from which all
measurements of arm are taken. The datum is
established by the manufacturer.
Moment
The product of the weight of an item multiplied by its
arm and expressed in inch-pounds. The total
moment is the weight of the aeroplane multiplied by
distance between the datum and the CG.
*In reference to loading, the correct technical term is 'mass' instead of 'weight' in all of the
terms in this section, however in everyday language and in current Cessna manuals the term
weight remains in use. In this context there is no difference in meaning between mass and
weight, and the terms may be interchanged.
MZFW
Maximum Zero The maximum permissible weight to prevent
Fuel Weight
exceeding the wing bending limits. This limit is not
always applicable for aircraft with small fuel loads.
BEW
Basic Empty
Weight
The weight of an empty aeroplane, including
permanently installed equipment, fixed ballast, full
oil and unusable fuel, and is that specified on the
aircraft mass and balance documentation for each
individual aircraft.
SEW
Standard
Empty Weight
The basic empty weight of a standard aeroplane,
specified in the POH, and is an average weight given
for performance considerations and calculations.
OEW
Operating
Empty Weight
The weight of the aircraft with crew, unusable fuel,
and operational items (galley etc.).
Payload
The weight the aircraft can carry with the pilot and
fuel on board.
Maximum
Ramp Weight
The maximum weight for ramp manoeuvring, the
maximum takeoff weight plus additional fuel for start
taxi and run-up.
MRW
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CESSNA 172 TRAINING MANUAL
MTOW
Maximum
Takeoff
Weight
The maximum permissible takeoff weight and
sometimes called the maximum all up weight,
landing weight is normally lower as allows for burn
off and carries shock loads on touchdown.
MLW
Maximum
Landing
Weight
Maximum permissible weight for landing. Sometimes
this is the same as the takeoff weight for smaller
aircraft.
Other
AFM
POH
PIM
Aircraft Flight These terms are inter-changeable and refer to the
Manual
approved manufacturer's handbook. General Aviation
manufacturers from 1976 began using the term
Pilot's
'Pilot's Operating Handbook', early handbooks were
Operating
called Owner's Manual, most legal texts use the term
Handbook
AFM.
Pilot
Information
Manual
A Pilot Information Manual is a new term, coined to
refer to a POH or AFM which is not issued to a
specific aircraft.
Useful Factors and Formulas
Conversion Factors
Lbs to kg
1kg =2.204lbs
kgs to lbs
1lb = .454kgs
USG to Lt
1USG = 3.785Lt
lt to USG
1lt = 0.264USG
Lt to Imp Gal
1lt = 0.22 Imp G
Imp.Gal to lt
1Imp G = 4.55lt
NM to KM
1nm = 1.852km
km to nm
1km = 0.54nm
NM to StM to ft
1nm = 1.15stm
1nm = 6080ft
Stm to nm to ft
1 stm = 0.87nm
5280ft
FT to Meters
1 FT = 0.3048 m
meters to ft
1 m = 3.281 FT
Inches to Cm
1 inch = 2.54cm
cm to inches
1cm = 0.394”
Hpa (mb) to “Hg
1mb = .029536”
“ Hg to Hpa (mb)
1” = 33.8mb
AVGAS FUEL Volume / Weight SG = 0.72
Litres
Lt/kg
kgs
Litres
lbs/lts
Lbs
1.39
1
0.72
0.631
1
1.58
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CESSNA 172 TRAINING MANUAL
Crosswind Component per 10kts of Wind
Deg
10
20
30
40
50
60
70
80
Kts
2
3
5
6
8
9
9
10
Formulas
Celsius (C) to
Fahrenheit (F)
Pressure altitude
(PA)
Standard
Temperature (ST)
Density altitude
(DA)
C = 5/9 x(F-32),
F = Cx9/5+32
PA = Altitude AMSL + 30 x (1013-QNH)
Memory aid – Subscale up/down altitude up/down
ST = 15 – 2 x PA/1000
ie. 2 degrees cooler per 1000ft altitude
DA = PA +(-) 120ft/deg above (below) ST
Specific Gravity
One in 60 rule
i.e. 120ft higher for every degree hotter than standard
SG x volume in litres = weight in kgs
1 degree of arc ≈ 1nm at a radius of 60nm
Rate 1 Turn Radius
i.e degrees of arc approximately equal length of arc at a
radius of 60nm
R = TAS per hour/60/π or TAS per minute/π
Radius of Turn Rule
of Thumb
Rate 1 Turn Bank
Angle Rule of
Thumb
R ≈ TAS per hour/180 (Where π (pi) ≈3.14)
Radius of Turn lead allowance ≈ 1% of ground speed
(This rule can be used for turning on to an arc – e.g. at
100kts GS, start turn 1nm before the arc limit)
degrees of bank in a rate one turn ≈ GS/10+7
Pilot's Operating Handbook Information
The approved manufacturer's operating handbook, which may be commonly
referred to as a Pilot's Operating Handbook (POH), an Aircraft Flight Manual
(AFM), or an Owners Manual, is issued for the specific model and serial number,
and includes all applicable supplements and modifications. It is legally required
to be on board the aircraft during flight, and is the master document for all flight
information.
In 1975, the US General Aviation Manufacturer's Association introduced the
'GAMA Specification No. 1' format for the 'Pilot's Operating Handbook' (POH).
This format was later adopted by ICAO in their Guidance Document 9516 in
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CESSNA 172 TRAINING MANUAL
1991, and is now required for all newly certified aircraft by ICAO member states.
Most light aircraft listed as built in 1976 or later, have provided Pilot's Operating
Handbooks (POHs) in this format.
GAMMA standardised the term 'Pilot's Operating Handbook' as the preferred
term for a manufacturer's handbook on light aircraft, however some
manufacturers still use different terms (see further explanation above under
definitions).This format aimed to enhance safety by not only standardising
layouts but also by creating an ergonomic format for use in flight. For this
reason the emergency and normal operating sections are found at the front of
the manual, while reference and ground planning sections are at the rear.
It is recommended that pilots become familiar with the order and contents of
each section, as summarised in the table below.
Section 1
General
Definitions and abbreviations
Section 2
Limitations
Specific operating limits, placards and specifications
Section 3
Emergencies Complete descriptions of action in the event of any
emergency or non-normal situation
Section 4
Normal
Operations
Section 5
Performance Performance graphs, typically for stall speeds,
airspeed calibration, cross wind calculation, takeoff,
climb, cruise, and landing
Section 6
Weight and
Balance
Section 7
Systems
Technical descriptions of aircraft systems, airframe,
Descriptions controls, fuel, engine, instruments, avionics and
lights etc.
Section 8
Servicing
Maintenance requirements, inspections, stowing, oil
and
requirements etc.
maintenance
Section 9
Supplements Supplement sections follow the format above for
additional equipment or modification.
Section 10
Safety
Information
Complete descriptions of required actions for all
normal situations
Loading specifications,
graphs or tables
limitations
and
loading
General safety information and helpful operational
recommendations which the manufacturer feels are
pertinent to the operation of the aircraft
For use in ground training, or reference prior to flight, this text should be read in
conjunction with the POH from on board the aircraft you are going to be flying.
Even if you have a copy of a POH for the same model C172, the aircraft you are
flying may have supplements for modifications and optional equipment which
affect the operational performance.
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CESSNA 172 TRAINING MANUAL
AIRCRAFT TECHNICAL INFORMATION
The Cessna 172 aeroplane is an all-metal, single engine, four-seat, high-wing
monoplane aircraft, equipped with tricycle landing gear and designed for general
utility purposes.
Illustration 1b Cessna 172 Plan and Profile Views
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CESSNA 172 TRAINING MANUAL
Models and Differences
The Cessna 172 has had a large number of different models and type variants
during its production history. Additionally there are a large number of
modifications provided for the airframe, instruments/avionics equipment and
electrics.
Speeds often vary between models by one or two knots, sometimes much more
for large changes or for significant type variants. Attempt has been made to
provide representative speeds for the series, but pilots must refer to the POH of
the aircraft they operate for correct speeds. All speeds have been converted to
knots and rounded up to the nearest 5kts. Generally multiple provision of figures
can lead to confusion for memory items and this application is safer for practical
use during conversion training.
 Note, speeds vary with type, modifications, weight, and density
altitude; The Pilot's Operating Handbook must be consulted for the
correct figures before flight.
During practical training reference should be made to the flight manual of the
aeroplane you will be flying to ensure that the limitations applicable for that
aeroplane are adhered to. Likewise when flying different models it should always
be remembered that MAUW, flap limitations, engine characteristics, limitations
and speeds are but a few examples of items that may vary from model to
model.
 Before flying different models, the Pilot's Operating Handbook should
be consulted to verify differences.
Main Differences by year of manufacturing
The following modification of Cessna 172 were made during years of production
of the aircraft:
• The 1957 model has a 145hp Continental engine;
• Model's after 1960 have a swept tail;
• In 1963 a rear window appeared as well as a single piece windshield and
longer elevator;
• 1964 model were equipped with electric flaps instead of the “Johnson Bar”;
• 1968 models switched to Lycoming 150hp engines.
• In 1971 the spring steel main landing gear was changed to tubular steel.
• In 1981 Cessna switched to a 160hp engine, and increased the gross weight
to 2400lbs but reduced flap travel of 30 degrees.
• 1996 and later models feature the Lycoming IO-360-L2A four cylinder, fuel
injected engine, an annunciator panel or optional Garmin G1000 EFIS avionics
suit.
A more comprehensive summary combined with serial numbers and model
numbers is contained in the Model History table on the following pages.
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CESSNA 172 TRAINING MANUAL
Naming Terminology
The C172 series manufactured by Cessna in Wichita, like most Cessna models,
started with the C172 followed by the C172A and continued sequentially up until
the C172 R and S, with the exception of the models J and O which never
completed certification. Each new model release superseding the previous, with
the exception of model variants, such as the 172RG and R172K.
Model Variants
Some models carried an alternate prefix or suffix to designate a specific
difference, or model variant, for example the R172K, P172D, and F172.
Reims 172
The F172 for models D through M, was made by Reims in France, and according
to Cessna there are no significant differences apart from the engines on models
prior to 1971 (F172K and earlier), however there are some differences in
manufacturing processes.
Cessna 175 Certified Aircraft
Although marketed as a C172, the P172D, R172E through H, R172K and
FR172K, and the C172RG were all designated as C175s, that is, they were
certified under the C175 type data certification sheet by the FAA.
The P172D, where the 'P' indicated the geared engine referred to as
“Powermatic” by Cessna. The different type designator also reflected a larger
distinction, the aircraft is nearly identical to the C175C and treated as such for
certification, it has little in common with the C172D except the year of
manufacture (1963).
The C172 RG – where the 'RG' designated a retractable Cessna as with other
models of Cessna. Produced between 1981 and 1985, the RG option was not
reintroduced when production commenced in 1996.
The prefix 'R' was originally given to the 210hp military version C172, made
specifically for the US Air Force, and should not be confused with the Reims ('F')
models or the retractable ('RG') models. The original military R172 was
produced for models R172E through to R172H, between 1964 and 1973, called
by the USAF a T41-B, C or D, depending on options (the C172H, originally made
for the USAF was called the T41-A). Most models retired into USAF aero-clubs, a
few are in civilian use, and some still remain in US and other air force
operations. These models led to the development of a civilian version, the
R172K given the name Hawk XP and the FR172K, Reims Hawk XP or Reims
Rocket, with the same engine de-rated to 195hp, produced between 1977 and
1981.
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CESSNA 172 TRAINING MANUAL
Model History Table
The table below summarises the model history versus serial number compiled
from the type data certification summaries (TDC) and from the technical
information in the Cessna maintenance manuals.
Model Name
Year Serial
Significant Changes and Features
Numbers
C172
1956
2800029174
1957
2917529999,
3600036215
1958
3621636965
1959
3696636999,
4600146754
Engine cowling changed for improved
cooling, instrument panel modified,
moving main flight control instruments
from central to left side of panel, in a
more direct line of sight of the pilot.
C172A
1960
46755 47746
The same as the basic 172 with a swept
vertical tail, and the first float plane
version was available. The 0-300
Continental engine was available as a C
or D type.
C172B C172 in
standard
version
and
Skyhawk
or
Skyhawk
II for
C172C luxury
version.
1961
1724774717248734
A deeper fuselage (shorter
undercarriage), new wind shield,
revised cowling and pointed propeller
spinner as well as external baggage
door and another new instrument panel
was introduced with the artificial
horizon centrally located. Usable fuel
39USG.
1962
1724873517249544
Maximum weight increased to 2250lbs,
optional key starter on deluxe version
(replaces standard pull starter),
auxiliary child seat available. Usable
fuel 36 USG.
by O. Roud & D. Bruckert © 2006, This Edition 2014
The first model C172, which was
basically a Cessna 170B with tricycle
gear, distinctive straight windowless
back, square vertical tail, and manual
flap, the Continental 6 cylinder O-300-A
or B engine producing 145hp at 2700hp
42USG fuel tank (37USG usable),
maximum weight of 2200lbs for the lad
plane, the seaplane was increased to
2220lbs where it remained through the
C172 model history.
Page 16
CESSNA 172 TRAINING MANUAL
Model Name
Year
Serial
Numbers
Significant Changes and Features
C172D
1963
1724954517250572
Cut-down rear fuselage and “Omnivision” rear windows replaced the
original 'straight-back' look, land-plane
weight increased to 2300lbs, and new
full rudder and brake pedals fitted.
1963
F1720001F1720018
Made by Reims in France, some
differences in manufacturing.
Continental O-300-D engine
manufactured by Rolls Royce.
1964
1725057317251822
Electrical fuses were replaced by circuit
breakers.
1964
F1720019F1720085
Made by Reims in France, some
differences in manufacturing.
C172F
1965
1725182317253392
Electric flaps were introduced, with a
three position toggle switch. This
model, along with the C172H was also
produced by the USAF as a T41-A.
F172F
Reims or 1965
French
172
F172D
Reims or
French
172
C172E
F172E
Reims or
French
172
F172-0086- Made by Reims in France, some
F172-0179 differences in manufacturing.
C172G
1966
1725339317254892
Minor modifications to propeller shaft
and spinner.
F172G
Reims or 1966
French
172
F1720180F1720319
Made by Reims in France, some
differences in manufacturing.
C172H
1967
1725489317256512
Nose strut shortened for reduced drag
and appearance. A modified engine
cowling and mountings reduced noise in
the cockpit and cowl cracking. The
generator is replaced with an alternator
for electrical power supply.
This model was also produced by the
USAF as a T41-A.
1967
F1720320F1720446
Made by Reims in France, some
differences in manufacturing.
F172H
Reims
French
172
F172H
Reims or 1968
French
172
F17200655 Made by Reims in France, some
differences in manufacturing.
F17200754
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CESSNA 172 TRAINING MANUAL
Model Name
Year
Serial
Numbers
Significant Changes and Features
Note: The type certifier “F172” designates a Reims C172, that is if the type
indicator has F in the front, it was built in Reims factory in France. Reims built
C172s, between 1963 and 1976. They are reported by Cessna maintenance
manuals, for maintenance purposes as being nearly identical to the C172
produced in Wichita except for the engines on some models.
C172I
1968
1725651317257161
Engine changed to 150hp Lycoming O320 E2D (“Blue Streak”) with higher
2000 hour overhaul time, 38USG
usable fuel.
C172K Skyhawk
1969
1725716217258486
Rear side windows enlarged,
redesigned fin, optional 52USG tanks.
Split bus bar now on all models.
F172K
Reims or
French
172
F17200755 Made by Reims in France, some
differences in manufacturing.
F17200804
C172K Skyhawk
1970
1725848717259223
Fibreglass drooping wing-tip.
C172L
Skyhawk
1971
1725922417259903
Landing light shifted from wing to nose.
Flat steel replaced by tubular steel
undercarriage.
Skyhawk
1972
1725990417260758
F172L
Reims or 1972
French
172
C172M Skyhawk
F17200805 Continental Rolls Royce engine changed
to standard C172 Lycoming O-320-E2D
F17200904 engine.
1973
1726075917261898
F172M Reims or 1973
French
172
F17200905
F17201034
C172M Skyhawk
1974
1726189917263458
F172M Reims or 1974
French
172
F17201035
F17201234
C172M Skyhawk
1726345917265684
1975
by O. Roud & D. Bruckert © 2006, This Edition 2014
Drooped leading edge wing introduced
for better low speed handling. Seaplane
flap reduced to 30 degrees.
Baggage compartment increased in
size.
Page 18
CESSNA 172 TRAINING MANUAL
Model Name
Year
Serial
Numbers
Significant Changes and Features
F172M Skyhawk
1975
F17201235
F17201384
C172M Skyhawk
1976
1726568517267584
F172M Skyhawk
1976
F17201385 This was the last standard model F172
on
made by Reims, see also FR172 under
Type Variants.
Airspeed changed from miles to knots,
instrument panel redesigned to include
more avionics, engine and fuel gauges
shifted to the more ergonomic position
on the left side of the instrument panel
above the master switch.
C172N Skyhawk/ 1977
Skyhawk
II
17261445,
1726758517269309
160hp Lycoming O-320-H2AD engine*
Flap selector changed to the safer and
more ergonomic 'pre-selector' arm
(replacing the 3 position toggle switch).
Adjustable rudder trim available,
notched lever. Usable fuel 40USG,
optional 54USG long range fuel tanks
(50USG usable).
1978
17261578,
1726931017270049
1727005117271034
14V electrical system changed to 28V.
Air conditioning now available as an
option.
HIGH VOLTAGE warning light changed
to LOW VOLTAGE, with sensors
incorporated in alternator control unit.
1979
1727103517272884
Limiting speed on first 10 degrees of
flap increased from 85kts to 110kts.
1980
17270050,
1727288517274009
*This engine was the first engine (excluding the 210hp military version)
designed to operate on 100/130 Octane fuel, previous engines were designed
for 80/87 Octane. Most aircraft engines have now been modified to operate on
100/130 or 100 Low Lead Aviation Gasoline (Avgas 100 and Avgas 100LL) with
80/87 (Avgas 80) now having only very limited availability.
C172P
Skyhawk
1981
1727401017275034
1982
1727503517275759
by O. Roud & D. Bruckert © 2006, This Edition 2014
Lycoming O-320 engine changed from
H2AD to D2J to address some design
issues.
Page 19
CESSNA 172 TRAINING MANUAL
Model Name
C172Q Cutlass
Year
Serial
Numbers
Significant Changes and Features
1983
1727576017276079
1984
1727608017276259
1985
1727626017276516
1986
1727651717276654
Flap reduced from 40 degrees to 30
degrees. Land-plane weight increased
from 2300 to 2400lbs. Optional 66USG,
62USG usable long range tanks with
wet wing available. From 1982, landing
lights shifted from cowl back to wing
with standard dual light fitting.
Low vacuum light included from
17275834.
1983
1727586917276054
1984
1727610117276211
Lycoming O-360 engine, developing
180hp at 2700rpm, maximum gross
weight 2550lbs.
C172R Skyhawk
1996- 17280001
2008 on
Lycoming 160hp fuel injected IO360
engine, de-rated at 2400rpm, optional
G1000 avionics, maximum weight
increased to 2450lbs, optional 2550
maximum weight kit, 53USG usable
fuel. Fixed rudder trim.
C172S Skyhawk
SP
1996
on
Engine power increased to 180hp with
maximum rpm increasing from 2400 to
2700 rpm, maximum weight 2550lbs.
172S8001
on
At the time of publication, only the C172S equipped with G1000 avionics, is
still in production.
Type Variants
The following aircraft, although marketed as Cessna 172s, are all certified under
the FAA Type Data Certificate of the Cessna 175. All contain significant
differences in power available, and airframe.
Model Name
Year Serial
Significant Changes
Numbers
P172D
P172D
Powerma 1963 P17257120 175hp Continental GO-300-E
tic
'Powermatic' geared engine, revised
P17257188 cowling with dorsal gearbox fairing.
This model was essentially a C175
Skylark, renamed in a failed attempt to
fix poor sales performance of the C175.
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
Model
Name
Year Serial
Numbers
Significant Changes
FP172D French or 1963 FP1720001 Reims version of P172D, made in
Reims
FP1720003 France , some differences in
Powerma
manufacturing.
tic
Note – many Cessna types have adopted the prefix of 'P' for a pressurised
aircraft, this model demonstrates one of the common exceptions.
US Air Force Models
R172E
USAF
1964 R1720001- Fitted with Continental IO360 engine,
T41B,C,D
R1720335 producing 210hp at 2800rpm,
maximum weight 2500lbs,
Certified on C175 type certification
sheet.
R172F
USAF
T41B,C,D
R1720336R1720409
R172G
USAF
T41B,C,D
R1720336- 2550 maximum weight
R1720409
R172H
USAF
1971 R1720445T41B,C,D
R1720494
1972 R1720495R1720546
1973 R1720547R1720620
Retractable Gear Model
C172RG Cutlass
RG
1980 172RG0001 Retractable undercarriage, Lycoming O172RG0570 360 engine developing 180hp, with
1981 172RG0571 three blade constant speed propeller,
172RG0890 gross weight 2650lbs. Total usable fuel
62USG. Adjustable rudder trim wheel.
1982 172RG0891
172RG1099 Popular with flight schools as a complex
1983 172RG1100 trainer.
172RG1144
Certified on C175 type certification
1984 172RG1145 sheet.
172RG1177
1985 172RG1178
172RG1191
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CESSNA 172 TRAINING MANUAL
Model
Name
Year Serial
Numbers
Significant Changes
R172K - Hawk XP Models
R172K
Hawk XP
1977 R1722000- 1977 had 14V electrical system,
R172272
otherwise similar to other Hawk XP's
described below.
1978 R1722725
R1722929
Called the Hawk XP with a Continental
IO-360K fuel injected engine and
1979 R1720680, constant speed propeller, de-rated to
R1722930 195hp at 2600rpm.
R1723199 Maximum weight increased to 2550lbs.
Also certified as C175.
1980 R1723200 1978 models on had 28V electrical
R1723399 system.
(except
Certified on C175 type certification
R1723398) sheet.
1981 R1723400
R1723454
FR172K Reims
Hawk XP
Flap reduced from 40 to 30 degrees as
with other models of C172.
1977 FR1720591 The Hawk XP model made by Reims in
FR1720620 France, some differences in
1978 FR1720621 manufacturing.
FR1720630
1979 FR1720631
FR1720655
1980 FR1720656
FR1720665
1981 FR1720666
FR1720675
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
Airframe
The airframe is a conventional semi-monocoque type consisting of formed sheet
metal bulkheads, stringers and stressed skin.
Semi-monocoque construction is a light framework covered by skin that carries
much of the stress. It is a combination of the best features of a strut-type
structure, in which the internal framework carries almost all of the stress, and
the pure monocoque where all stress is carried by the skin.
The fuselage forms the main body of the aircraft to which the wings, tail section
and undercarriage are attached. The main structural features are:
Q
front and rear carry through spars for wing attachment;
Q
a bulkhead and forgings for landing gear attachment at the base of
the rear door posts;
Q
a bulkhead and attaching plates for strut mounting;
Q
four stringers for engine mounting attached to the forward door
posts.
Illustration 2a Fuselage Stations
The construction of the wing and empennage sections consists of:
Q
a front (vertical stabilizer) or front and rear spar (wings/horizontal
stabilizer);
Q
formed sheet metal ribs;
Q
doublers and stringers;
Q
wrap around and formed sheet metal/aluminium skin panels;
Q
control surfaces, flap and trim assembly and associated linkages.
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
Illustration 2b Wing Construction
The front spars are
equipped with wing-tofuselage and wing-tostrut attach fittings. The
aft spars are equipped
with
wing-to-fuselage
attach fitting, and are
partial-span spars. The
wings
contain
the
integral i.e. non bladder
type fuel tanks.
The empennage or tail
assembly consists of the
vertical stabilizer and
rudder,
horizontal
stabilizer and elevator.
Seats and Seat Adjustment
The seating arrangement consists of
two separate adjustable seats for the
pilot and front passenger, a split-back
fixed seat in the rear, and a child's seat
(if installed) aft of the rear seat.
The pilot and copilot seats are
adjustable in forward and aft position,
and in most models also for seat
height and back inclination.
Illustration 2c Seat Rail
When adjusting the seats forward and
aft, care should be taken to ensure the position is locked. Seat locks may be
fitted to prevent inadvertent movement, which can cause an accident if
occurring at a critical phase of flight. Seat locks are spring loaded to the locked
position, and must be pulled out before the seat can be moved aft, as an
additional safe guard to the main seat lock. Seat back and height should be
adjusted to ensure adequate visibility and control before start-up.
Doors
There are two entrance doors provided, one on the left and one on the right,
and a baggage door at the rear left side of the aircraft.
The door latch on early models was not locked, however on later models
rotation of the inside handle 90 degrees provided a latched and locked position.
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
To open the doors from outside the aeroplane, utilize the recessed door handle
by grasping the forward edge of the handle and pulling outboard. If the door is
locked from the inside, it will be impossible to grasp the door handle.
Illustration 2d Door Lock
The latter type of inside door handle has three positions, and a placard at its
base which reads OPEN, CLOSE, and LOCK. The handle is spring-loaded to the
CLOSE (up) position. When the handle is rotated to the LOCK position, an overcentre action will hold it in that position.
The latching mechanism is similar in most single engine Cessna aircraft and is
provided by a rack and pinion type unit. It is vital that the teeth are meshed
prior to attempting to lock the mechanism as damage to the teeth will occur if it
is forced. When the teeth become warn it may become difficult to mesh the
locking mechanism without pressure on the door. It is also possible to achieve
locking only on the last tooth of the rack gear where upon vibration or forces in
flight may cause the door to open, the security of the door should be checked by
positive pressure prior to takeoff.
Handle modifications are available with a locking pin that ensures the door is in
the correct position when closed, and which prevent the handle from being
lowered if the pin is not flush. These modifications are recommended and
minimise the risks of doors inadvertently opening is flight.
Baggage Compartment
The baggage compartment consists of the area from the back of the rear
passenger seats to the aft cabin bulkhead. A baggage shelf, above the wheel
well, extends aft from the aft cabin bulkhead. Access to the baggage
compartment and the shelf is gained through a lockable baggage door on the
left side of the airplane, or from within the airplane cabin. A baggage net with
six tie-down straps is provided for securing baggage, and is attached by tying
the straps to tie-down rings provided in the airplane.
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
When loading the airplane, children should not be placed or permitted in the
baggage compartment.

Any material that may be hazardous to the airplane or occupants should
never be placed anywhere in the aircraft. This includes items such as petrol ferry
tanks, lead acid batteries, common household solvents such as paint thinners
and many more. Items such as these can cause life threatening consequences
from incapacitation due to exposure to leaking fumes, cabin fire caused by
spillage combined with a static spark, explosion under pressure changes, or
result in serious corrosion damage to the airframe. If any doubt exists, consult
the IATA guidelines for permitted quantities of dangerous goods.

When using an approved auxiliary child seat, it is important to ensure that
loading is completed within the aircraft limits, for the maximum mass and the
position of the centre of gravity. More details on loading are provided in the
Performance Section.
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
Flight Controls
The aeroplane’s flight control system consists of conventional aileron, rudder
and elevator control surfaces. The control surfaces are manually operated
through mechanical linkages to the control wheel for the ailerons and elevator,
and rudder/brake pedals for the rudder. A manually-operated elevator trim tab is
provided and installed on the right elevator.
The control surfaces are formed in a similar way to the wing and tail section with
the inclusion of the balance weights, actuation system (control cables etc) and
trim tabs. Control actuation is provided by a series of push-pull rods, bellcranks, pulleys and cables with the required individual connections.
Elevator
The elevator is hinged to the rear part of the horizontal stabilizer on both sides.
The main features are:
Q
An inset hinge with balance weights;
Q
Adjustable trim tab on the right side of the elevator.
The leading edge of both left and right elevator tips incorporate extensions
which contain the balance weights which aerodynamically and mechanically
assists with control input reducing the force required to move the control.
Illustration 3a Elevator Linkages
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CESSNA 172 TRAINING MANUAL
Rudder
The rudder forms the aft part of the vertical stabilizer. The main features include
Q
Horn balance tab and balance weight;
Q
Either a fixed trim tab, or an adjustable rudder trim system.
Illustration 3b Rudder Travel
The top of the rudder incorporates a leading edge extension which contains a
balance weight and aerodynamically assists with control input in the same way
as the elevator hinge point.
The rudder movement is limited by a stop at 16 to 24 degrees either side of
neutral depend on the model of the aeroplane. Rudder linkage is additionally
connected to the nose wheel steering to assist with ground control.
Models before 1977 and after 1996 had a fixed rudder trim. The models in
between have an adjustable rudder trim tab. The C172RG has an adjustable
trim wheel.
Ailerons
Conventional hinged ailerons are attached to the trailing edge of the wings. Main
features of the aileron design include:
Q
A forward spar containing aerodynamic “anti-flutter” balance weights;
Q
“V” type corrugated aluminum skin joined together at the trailing edge;
Q
Differential and Frise design.
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
The ailerons control system additionally includes:
Q
Sprockets and roller chains;
Q
A control “Y” which interconnects the control wheel to the aileron cables.
Differential and Frise Ailerons
The ailerons incorporate both Differential
and Frise design.
Differential refers to the larger angle of
travel in the up position to the down
position, increasing drag on the downgoing wing.
Illustration 3d Frise Ailerons
Illustration 3c Differential Ailerons
Frise ailerons are constructed so that the
forward part of the up-going aileron
protrudes into the air stream below the
wing to increase the drag on the downgoing wing. Both features acting to reduce
the effect of Adverse Aileron Yaw, reducing
the required rudder input during balanced
turns. These features have the additional
advantage of assisting with aerodynamic
balancing of the ailerons.
Illustration 3e Control Yoke
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
Trim
The Cessna 172
aircraft
has
a
manually
or
electrically
operated elevator
trim system and a
fixed or adjustable
rudder
trim
system, depending
on the model.
Elevator Trim
One trim tab is
provided on the
right side of the
Illustration 3f Elevator Trim Connections
elevator, spanning
most of the the rear section of the right elevator.
The trim tab moves opposite to the control surface, reducing the aerodynamic
force on the control surface in
order to hold the selected
position.
Trimming
is
accomplished
through
the
elevator trim tab by turning the
vertically
or
horizontally
mounted trim control wheel.
The trim tab control wheel
depending on the model may be
mounted on the centre console
or in the cockpit floor, as can be
seen in the illustration on the
following page.
Illustration 3g Trim Control Action
Forward or up rotation of the
trim wheel will trim nose-down,
conversely, aft or down rotation
will trim nose-up.
A portion of the wheel extends through the control wheel cover and when
rotated, operates the tab through roller chains, cables, an actuator, and a pushpull rod. A position indicator at the trim tab control wheel indicates nose attitude
of the aircraft. The trim setting for takeoff is usually clearly placarded on the
trim wheel.
by O. Roud & D. Bruckert © 2006, This Edition 2014
Page 30
CESSNA 172 TRAINING MANUAL
ELEVATOR TRIM:
NEW MODELS
ELEVATOR TRIM:
OLDER MODELS
Illustration 3h Elevator Trim Wheel
Electric Elevator Trim
Some Cessna 172 models have a factory installed, or post manufacturer,
autopilot system. Any full auto-flight system fitted to the aircraft, will include an
electrical trim.
The electrical trim consists of a split rocker type switch, mounted on top of the
left side of the control wheel.
The trim is activated by pressing both sides forward or aft with your left thumb.
Activating one side only should not activate the trim.
To test the trim, ensure when both sides are depressed the trim moves in the
correct direction, forward and aft, then to check the split switch, ensure when
each side is depressed individually, the trim does not activate.

The 'split' design of the split rocker switch is aimed to prevent inadvertent
application of trim, so it is important to test it carefully.

It's also important, when an electric trim is installed, to know the location of
the trim circuit breaker. In case of a trim run away, this should be immediately
pulled out to disconnect the electric trim.
Rudder Trim
The following summarises the Cessna 172 rudder trim installations:
Q
Prior to 1977 and from 1996 on, a fixed rudder trim tab;
Q
C172 1977-1986 and C172XP 1977-1981 rudder trim control tab;
Q
C172RG-1980-85 rudder control wheel.
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CESSNA 172 TRAINING MANUAL
All models prior to
1977 and after 1996,
contain
a
fixed
rudder
trim.
The
fixed trim is adjusted
to maintain balance
at
normal
cruise
power settings, and
can only be adjusted
on the ground by
maintenance
personnel.
Note,
the
fixed
rudder trim is very
delicate and should
not be used as a
handle to check the
rudder!
On models between
1977 and 1986, a
rudder
trim
is
installed to provide a
Illustration 3i Rudder Trim Connections
means of assisting
with directional control for extended climbs or low power operations.
The rudder trim compensates for engine torque by allowing selection of
sustained slight rudder control in the direction necessary for maintaining
balanced flight. During cruise, the rudder trim may be adjusted to maintain
balance for the selected power setting and airspeed.
The rudder trim, if installed, is operated by either a control tab (in the C172,
and R172) or a control wheel (in the
C172RG), mounted on the centre control
pedestal.
The rudder trim control is connected via a
bell crank to a bungee, which is directly
connected to the rudder pedal control bar
and thus to the rudder itself. It should be
noted the rudder does not have trim tab,
trimming is accomplished by changing
force on the rudder pedals through the
bungee, and thus changing the position of
the rudder.
Illustration 3j Rudder Trim Lever
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CESSNA 172 TRAINING MANUAL
With a trim lever, trimming is
accomplished by lifting the trim
lever up to clear a detent, then
moving it either left or right to
desired trim position (as shown
in the picture below). Moving the
trim to the right will trim noseright, conversely, moving the
lever to the left will trim noseleft.
With a rudder trim control wheel,
rotation of the control wheel to
the right provides "NOSE RIGHT"
trim, and left rotation provides
"NOSE LEFT" trim.
A rudder trim position indicator
indicates the trim setting when
the
trim
control
wheel
is
adjusted.
Flaps
The flaps are constructed in
Illustration 3k Rudder Trim Wheel Connections
the same way to the ailerons,
except without balance weights, and with the addition of a formed sheet metal
leading edge section.
Maximum flap extension is either 40 degrees on earlier models or 30 degrees on
later models. The reduction from 40 to 30 degrees maximum flap occurred on
the seaplane in 1973 with the C172M, and on the the land plane in 1981 with
the C172P.
Illustration 3l Slotted Fowler Flap
by O. Roud & D. Bruckert © 2006, This Edition 2014
The wing flaps are of the
single-slot, fowler type. Both
design features act to further
reduce the stalling speed.
The single slot modifies the
direction of the airflow to
maintain laminar flow longer.
The fowler design increases
the size of the wing surface
area on extension.
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CESSNA 172 TRAINING MANUAL
Wing flaps are roller-mounted on slotted tracks to enable rearward movement as
they are lowered, thus increasing the wing area and altering the aerofoil shape
to provide increased lift and drag.
The Cessna 172 model series has 3 different types of the flap systems:
Q
manually operated flaps, prior to 1965;
Q
electrically controlled and actuated flaps with toggle control switch,
from 1965-1976; or
Q
electrically controlled and actuated flaps with a pre-select control
lever, from 1977 on.
Manually Operated Flap (Prior to 1965)
Models prior to 1965 were equipped with a manually operated flap system. The
flaps are operated by a hand lever located between the front seats. A ratchet
mechanism with a “thumb-release”
button on the end of the handle, holds
the flap lever in the desired position.
The system installed on the early
models of C172 consists of:
Q
an actuation lever;
Q
locking push button;
Q
mechanical linkages to the
flap;
Actuation of the manual flap requires
depressing the locking push button and
raising or lowering the flap to the
Illustration 3m Manual Flap
desired position. Releasing the push
button will allow the flap to lock into the next position. If you are unfamiliar with
manual operation raise and lower the flaps into each position before flight until
you are comfortable with the selections. Care should be taken, especially with
raising the flap, to ensure the correct position is selected.
Mechanical flap levers are directly linked to the flaps, so the forces required to
lower the flaps are directly related to the air pressure on the flaps, that is they
are directly related to the indicated airspeed. Extending flaps close to the flap
limiting speed should be avoided in all cases, but with a manual flap lever it
cans also be physically difficult to complete. Proper approach planning should be
adhered to to avoid this situation.
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CESSNA 172 TRAINING MANUAL
Illustration 3n Manual Flap Connections
Electric Flap (1965 on)
The flap system on the 1965 and later models is electrically actuated. The
system consists of an electric motor driving a transmission that operates the
right flap drive pulley which is linked to the right flap. The right and left drive
pulleys are interconnected by cables to insure duplicate motion of both flaps.
INDICATOR
DETENT
LIMITING
SPEED
Illustration 3o Flap Pre-Selector
Flap Pre-selector (1977 and later)
Electrical power to the motor is controlled by
two micro-switches mounted on a floating
arm assembly, through a camming lever and
follow-up control. They are extended or
retracted by positioning the flap lever on the
instrument panel to the desired flap deflection
position.
The switch lever is moved up or down in a
slot in the instrument panel that provides
mechanical stops at the 10, 20 and 30 degree
positions. For settings greater than 10
degrees, move the switch level to the right to
clear the stop and position it as desired. A
scale and pointer on the left side of the switch
level indicates flap travel in degrees. The
maximum deflection of the flaps in the model
pictured is 30 degrees.
The flap system is protected by a 15-ampere circuit breaker, labelled FLAP, on
the right side of the instrument panel.
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When the flap control lever is moved to the desired flap setting, an attached
cam trips one of the micro-switches, activating the flap motor. As the flaps move
to the position selected, the floating arm is rotated by the follow-up control until
the active micro-switch clears the cam, breaking the circuits and stopping the
motor. To reverse flap direction the control lever is moved in the opposite
direction causing the cam to trip a second micro-switch which reverses the flap
motor. The follow-up control moves the cam until it is clear of the second switch,
shutting off the flap motor. Failure of a micro-switch will render the system
inoperative without indication as to why. Limit switches at the flap actuator
assembly control flap travel as the flaps reach the full UP or DOWN positions.
Toggle Switch (1965-1976)
Earlier models C172 aeroplanes were fitted with a toggle switch for flap
actuation.
The switch is a three position, double-throw switch, with selections for UP, OFF
and DOWN. The flap position transmitter is mechanically connected to right flap
drive pulley and electrically transmits position information to the flap position
indicator located on the instrument panel.
Selection requires holding the switch in the desired position until the setting
required is achieved. The system is most effectively used by application of
reliable timing backed up by intermittent monitoring of the gauge.
In flight at 100mph, indicated airspeed,
the flaps should take approximately 9
seconds to fully extend and 7 seconds
to retract. On the ground with minimal
air resistance, and with the engine
running so the generator is supplying
power, the flaps take approximately 7
seconds to extend or retract.
To select from zero to 10 degrees the
toggle switch is moved to the down
position
for
3-4
seconds
while
intermittently monitoring the flap
indicator, and then returned to neutral
when the desired. position is reached,
Illustration 3p Flap Toggle Switch
likewise from 10 degrees to 20 degrees
etc.

The flap toggle switches had the inherent design fault of making it very easy
to accidentally select the flaps fully up or fully down. This situation occurs when
the neutral position is not re-selected correctly after flap operation.
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This error invariable occurred in two ways:
Q
Flap was selected up or down and forgotten about (i.e. the pilot
thereafter omitted to return the switch to neutral), resulting in full travel
up or down;
Q
After selection, when returning to neutral, the selector is moved too far,
instead of neutral the flap begins travelling in the opposite direction.
Should the aircraft you are flying have a toggle switch for a flap lever remember
to take particular care with selection to prevent these errors.
A transmission is connected to and actuates the right flap drive pulley. This
transmission converts the rotary motion of the electric motor to the push-pull
motion needed to operate the flaps. The transmission will free-wheel at each
end of its stroke; therefore, if working correctly, it cannot be damaged by
overrunning when lowering or raising the flaps. If there is a fault on the flap
transmission, there is a possiblity it may over-run, as a safe-guard, it is
important to ensure the motor ceases operating when the neutral position is
selected.
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Landing Gear
The landing gear is of the tricycle
type with a steerable nose wheel
and two fixed main wheels. The
landing gear may be equipped with
wheel fairings for reducing drag.
The steerable nose wheel is
mounted on a forked bracket
attached to an air/oil (oleo) shock
strut. The shock strut is secured to
the tubular engine mount.
Nose
wheel
steering
is
accomplished by two spring-loaded
steering bungees linking the nose
gear steering collar to the rudder
pedal bars. Steering is available up
to 10 degrees each side of neutral,
after which brakes may be used to
gain a maximum deflection of 30
Illustration 4a Nose Wheel Construction
degrees right or left of centre.
During flight the nose wheel leg extends fully, bringing a locking mechanism into
place which holds the nose wheel central and free from rudder pedal action.
The Cessna 172RG incorporates the standard landing gear arrangement with a
modification for extension and retraction.
The landing gear operating system is
electrically actuated and hydraulically
controlled as with most of the retractable
single engine Cessna aircraft.
Shock Absorption
Illustration 4b Shock Strut and Shimmy
Damper
Shock absorption on the main gear is
provided by the tabular spring-steel main
landing gear struts and air/oil nose gear
shock strut. Because of this the main
gear is far more durable than the nose
gear and is thus intended for the full
absorption of the landing.
Correct extension of shock strut is
important
to
proper
landing
gear
operation. Too little extension will mean no
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shock absorption resulting in shock damage during taxi and landing, too much
and proper steering will become difficult and premature nose wheel contact on
landing may occur. Should the strut extend fully while on the ground the locking
mechanism will cause a complete loss of nose wheel steering.
A hydraulic fluid-filled shimmy damper is provided to minimize nose wheel
shimmy. The shimmy damper offers resistance to shimmy (nose wheel
oscillation) by forcing hydraulic fluid through small orifices in a piston. The
dampener piston shaft is secured to a stationary part and the housing is secured
to the nose wheel steering collar which moves as the nose wheel is turned right
or left, causing relative motion between the dampener shaft and housing. This
movement in turn provides the resistance to the small vibrations of the nose
wheel.
Hydraulic System-Retractable Landing Gear (C172RG
Only)
The landing gear extension, retraction, and main gear down lock release
operation is accomplished by hydraulic actuators powered by an electricallydriven hydraulic power pack. The power pack is located aft of the firewall
between the pilot's and copilot's rudder pedals. The hydraulic system fluid level
may be checked by utilizing the dip stick/filler cap located on the top left side of
the power pack adjacent to the motor mounting flange. The system should be
checked at 25-hour intervals. If the fluid level is at or below the ADD line on the
dipstick, hydraulic fluid (MIL-FI-5606) should be added to bring the level to the
top of the dipstick/filler cap opening.
The power pack's only function is to supply hydraulic power for operation of the
retractable landing gear. This is accomplished by applying hydraulic pressure to
actuator cylinders which extend or retract the gear. A normal operating pressure
of 1000 PSI to 1500 PSI is automatically maintained in the landing gear system,
and is sufficient to provide a positive up pressure on the landing gear. It is
protected by relief valves which prevent high pressure damage to the pump and
other components in the system. The electrical portion of the power pack is
protected by a 30-amp push-pull type circuit breaker switch, labeled GEAR
PUMP, on the left switch and control panel.
The hydraulic power pack is turned on by a pressure switch on the power pack
when the landing gear lever is placed in either the GEAR UP or GEAR DOWN
position. When the lever is placed in the GEAR UP or GEAR DOWN position, it
mechanically rotates a selector valve which applies hydraulic pressure in the
direction selected. As soon as the landing gear reaches the selected position, a
series of electrical switches will illuminate one of two indicator lights on the
instrument panel to show gear position and completion of the cycle. After
indicator light illumination, (GEAR DOWN cycle only), hydraulic pressure will
continue to build until the power pack pressure switch turns the power pack off.
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During normal operations, the landing gear should require from 5 to 7 seconds
to fully extend or retract.
The nose gear and main gear incorporate positive mechanical down locks. Also,
the nose gear has mechanically-actuated wheel well doors. The doors open
when the nose gear extends, and close when it retracts.
Landing Gear Selector
The landing gear selector lever is located on the switch and control panel to the
right of the electrical switches. The lever has two positions, labeled GEAR UP
and GEAR DOWN, which give a mechanical indication of the gear position
selected. From either position, the lever must be pulled out to clear a detent
before it can be repositioned; operation of the landing gear system will not
begin until the lever has been repositioned. After the lever has been
repositioned, it directs hydraulic pressure within the system to actuate the gear
to the selected position.
Landing Gear Position Indicator Lights
Two position indicator lights, adjacent to the landing gear control lever, indicate
that the gear is either up or down and locked. Both the gear- up (amber) and
gear-down (green) lights are the press-to-test type, incorporating dimming
shutters for night operation. If an indicator light bulb should burn out, it can be
replaced in flight with the bulb from the remaining indicator light.
Landing Gear Operation
To retract or extend the landing gear, pull out on the gear lever and move it to
the desired position. After the lever is positioned, the power pack will create
pressure in the system and
actuate the landing gear to the
selected position. During a
normal cycle, the gear retracts
fully or extends and locks, limit
switches close (GEAR DOWN
cycle only), and the indicator
light comes on (amber for up
and green for down) indicating
completion of the cycle. After
indicator
light
illumination,
during a GEAR DOWN cycle, the
power pack will continue to run
until the fluid pressure reaches
1500 PSI, opens the pressure
switch, and turns the power
Illustration 4c C172RG Ground (Squat) Switch
pack
off.
Whenever
fluid
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CESSNA 172 TRAINING MANUAL
pressure in the system drops below 1000 PSI, the pressure switch will close and
start power pack operation, except when the nose gear safety (squat) switch is
open.
The safety (squat) switch, actuated by the nose gear, electrically prevents
inadvertent retraction whenever the nose gear strut is com pressed by the
weight of the airplane. When the nose gear is lifted off the runway during
takeoff, the squat switch will close. If the system pressure has dropped below
1000psi, this will cause the power pack to operate for a few seconds to return
system pressure to 1500psi. A "pull-off" type circuit breaker is also provided in
the system as a maintenance safety feature. With the circuit breaker pulled out,
landing gear operation by the gear pump motor is prevented. After maintenance
is completed, and prior to flight, the circuit breaker should be pushed back in.
Emergency Hand Pump
A hand-operated hydraulic pump, located between the front seats, is provided
for manual extension of the landing gear in the event of a hydraulic system
failure. The landing gear cannot be retracted with the hand pump. To utilize the
pump, extend the handle forward, and pump vertically. For malfunctions of the
hydraulic and landing gear systems, refer to Section 3 (Emergencies) of the
Pilot Operation Handbook.
Landing Gear Warning System
The retractable gear has a warning system designed to help prevent the pilot
from inadvertently making a wheels-up landing. The system consists of a
throttle actuated switch which is electrically connected to a dual warning unit.
The warning unit is connected to the airplane speaker.
When the throttle is retarded below approximately 12 inches of manifold
pressure at low altitude (master switch on), the throttle linkage will actuate a
switch which is electrically connected to the gear warning portion of a dual
warning unit. If the landing gear is retracted (or not down and locked), an
intermittent tone will be heard on the airplane speaker. An interconnect switch in
the wing flap system also sounds the horn when the wing flaps are extended
beyond 20 deg with the landing gear retracted.
See more under Landing Gear Emergencies, in the Emergency section.
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Landing Gear System Schematic (C172RG)
Illustration 4d Retractable Landing Gear Schematic
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Brakes
Each main gear wheel is
equipped with a hydraulically
actuated disc-type brake on the
inboard side of each wheel.
When
wheel
fairings
are
installed the aerodynamic fairing
covers each brake.
The hydraulic brake system is
comprised of:
Q
two master cylinders
immediately forward
of the pilot’s rudder
Illustration 4e Brake Cylinders
pedals;
Q
a brake line and hose connecting each master cylinder to its wheel
brake cylinder;
Q
a single-disc, floating cylinder-type brake assembly on each main
wheel.
The brake master cylinders located immediately forward of the pilot’s rudder
pedals, are actuated by applying pressure at the top of the rudder pedals. A
small reservoir is incorporated into each master cylinder for the fluid supply.
Mechanical linkage permits the co-pilot (instructor) pedals to operate the master
cylinders.
Through their operation it is easily possible to inadvertently use brakes whilst
under power. This increases war on brakes and increases stopping distances.
Prior to applying brakes to stop the aircraft always ensure the throttle is closed.
Park Brake
Two different types of parking brake systems are employed in the C172 series.
The earlier type, has a knob-operated control which actuates locking levers on
the master cylinders. The levers trap pressure in the system after the master
cylinder piston rods have been depressed by toe operation of the rudder pedals.
The method of using the park brake with this system is:
1. Apply pressure on the brakes (the top of the rudder pedals);
2. Pull parking brake control to the out position;
3. Release toe pressure (checking to ensure the brakes are holding);
4. Release park brake control .
To release the parking brake, depress the pedals and ensure the control knob is
full in. The park brake should be released when securing the aircraft after
installing chocks to prevent locking.
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This type of park brake tends to have problems with the activation and release,
and with the fact that the pilot is unable to ascertain by the position of the lever
if the park brake is applied or not.
All later models are fitted with a handle type parking brake system, which is
comprised of a pull-type handle and mechanical connections which are linked to
the rudder pedal assembly. Pulling aft on the brake handle applies mechanical
pressure to the rudder pedals, activating the brakes and locks the handle in
place. Turning the handle 90 degrees will release the parking brake and allow for
normal operation through the rudder pedals.
For park brakes with a handle type
activation, the method of using the
parking brake system is:
1. Apply pressure on the toe brakes (the
top of the rudder pedals);
2. Pull parking brake control to the out
position;
3. Rotate the control downwards to the
locked position;
4. Release toe pressure (checking to
ensure the brakes are holding).
Illustration 4f Handle Type Park Brake
The lever is then in the extended position when the park brake is activated.
To release the parking brake apply the reverse procedure, pull the park brake
and rotate in the reverse direction then push fully in towards the control panel.
The park brake should be released when securing the aircraft after installing
chocks to prevent brakes locking or binding with changes in ambient conditions
while parked.
In this system there is no need to hold the brakes, however prior to setting the
park brake and prior to releasing the park brake, the toes should usually be
firmly on the brakes, to ensure the aircraft does not move.
Towing
Moving the aircraft by hand is best accomplished by using the wing struts and
landing gear struts as a pushing point. A tow bar attached to the nose gear
should be used for steering and manoeuvering the aircraft on the ground. When
towing the aircraft, never turn the nose wheel more then 30 degrees either side
of center or the nose gear will be damaged.
When no tow bar is available, the aircraft may be manoeuvered by pressing
down on the tail section, raising the nose wheel off the ground to enable
turning . Never press on the control surfaces or horizontal/vertical stabilizers for
manoeuvring points, as structural damage will occur to the mounting points or
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CESSNA 172 TRAINING MANUAL
skin surface. The best position to press down on is the most rearward section of
fuselage, immediately forward of the vertical stabilizer leading edge. This
method also provides easy steering by pushing on the side of the fuselage in the
direction of turn.
Illustration 4g Tow Bars
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CESSNA 172 TRAINING MANUAL
Engine and Propeller
The C172 is powered by a Continental or Lycoming horizontally opposed, aircooled, engine.
Illustration 5a Lycoming IO320 Engine
Early models of 172, before 1967, are powered with Continental O-300, six
cylinder engine. In 1968 this was replaced with Lycoming 0-320, four cylinder
engine, although the F172 retained the Continental O-300-D engines until 1971.
The O-320 engine had three variations before being replaced by the O-360
engine. The O-360 had two variations before being replaced by the introduction
of the fuel injected IO-360 engine in the “restart” models (1996 and later).
The Cessna R172K, like it's predecessors, the R172E to H is powered by a six
cylinder Continental IO-360, de-rated with lower maximum rpm to 195hp.
The engine designator O means the engine is normally aspirated, and I indicates
fuel injection. The numbers (eg. 300, 320, 360) indicate the cubic capacity of
the engine. The horsepower developed varies with a number of factors including
the engine design, performance, and maximum rpm.
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CESSNA 172 TRAINING MANUAL
The Cessna 172 engines have the following specifications and power
development at sea level:
Q
Continental O-300 – 145 horsepower at 2700 rpm, 6 cylinder (C172 to
C172H);
Q
Continental O-300-D – 145 horsepower at 2700 rpm, 6 cylinder (F172E
to F172M);
Q
Continental GO-300-D – 175 horsepower at 3200 rpm, 6 cylinder, geared
engine, constant speed propeller (P172);
Q
Continental IO-360-H and HB – 210 horsepower at 2800 rpm, 6 cylinder,
(R172E to R172H);
Q
Lycoming O-320 E2D – 150 horsepower at 2700 rpm, 4 cylinder (C172L
to C172M);
Q
Lycoming O-320-H2AD – 160 horsepower at 2700 rpm, 4 cylinder
(C172N);
Q
Lycoming O-320-D2J – 160 horsepower at 2700 rpm, 4 cylinder (C172P);
Q
Lycoming O-360-A4N – 180 horsepower at 2700 rpm, 4 cylinder
(C172Q);
Q
Continental IO-360-K and KB – 195 horsepower at 2600 rpm, 6 cylinder
(R172K);
Q
Lycoming O-360-FIA6 – 180 horsepower at 2700 rpm, 4 cylinder
(C172RG);
Q
Lycoming IO-360-L2A – 160 horsepower at 2400 rpm (may be modified
to 2700rpm, 4 cylinder (C172R);
Q
Lycoming IO-360-L2A – 180 horsepower at 2700 rpm, 4 cylinder
(C172S).
Illustration 5b Lycoming IO360 Side View
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Illustration 5c Lycoming IO360 Top View
The Cessna 172 is usually equipped with a two bladed, fixed pitch, aluminum
alloy McCauley propeller. The propeller rotates clockwise when viewed from the
cockpit. The propeller is approximately 1.90 metres (75 inches) in diameter,
increasing slightly to 2.0 metres (79 inches) for the float plane version.
The C172RG and the US Air Force R172 models have a three-bladed constant
speed propeller.
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CESSNA 172 TRAINING MANUAL
Engine Controls
The engine control and monitoring system
consists of:
Q
Throttle control;
Q
Propeller pitch control (constant
speed propeller - R172/FR172 and
RG model only);
Q
Mixture control;
Q
Carb heat selector;
Illustration 5d Power Controls
Q
Engine monitoring gauges:
• Tachometer;
• Manifold pressure (constant speed propeller – R172/FR172, and
C172RG models);
•
Fuel flow indicators (fuel injected models – R172, C172R, C172S
only);
• Oil temperature and pressure;
Q
Some optional equipment:
•
Cylinder Head Temperature (CHT) indicator, Carburettor temperature
indicator;
•
Exhaust gas temperature (EGT) indicator;
•
Fuel pressure indicators;
•
Annunciator panel (C172R and C172S conventional);
•
G1000 engine monitoring (systems annunciators and lean assist) –
standard with G1000 option.
Throttle
Engine power is controlled by a throttle, located on the lower center portion of
the instrument panel.
Throttle in Open Position
Throttle in Closed Position
Illustration 5e Throttle Butterfly
The throttle controls a throttle valve (or butterfly) – an oval metal disc pivoted
on a central spindle that is perpendicular to the axis of the carburettor’s
manifold. The closed position of the valve is when the disc is rotated to an angle
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of about 70 degrees to the axis of the manifold, preventing all but enough
fuel/air for idling to pass through the manifold. When the valve is rotated to a
position parallel to the axis of the manifold it offers very little restriction to
airflow. This is the fully open position of the valve providing maximum fuel/air
mixture to the manifold.
The throttle control operates conventionally as follows:
Q
full forward position, the throttle is open and the engine produces
maximum power,
Q
full aft position, it is closed and the engine is idling or windmilling.
Throttle Friction Nut
A friction lock, which is a round knurled disk, is located at the base of the
throttle and is operated by rotating the lock clockwise to increase friction or
counterclockwise to decrease it. This allows for reducing friction for smooth
operations when frequent or large power changes are required or increasing
friction when a fixed power setting or minimum changes are required.
Mixture
The mixture control, mounted on the right of the throttle, is a red vernier type
control.
The mixture control is used for adjusting fuel/air ratio in the conventional way as
follows:
Q
full forward position is the fully rich position (maximum fuel to air
ratio);
Q
full aft position is the idle cut-off position (no fuel).
For fine adjustments, the control may be moved forward by rotating the vernier
knob clockwise (enriching the mixture), and aft by rotating it counterclockwise
(leaning the mixture). For rapid or large adjustments, the control may be moved
forward or aft by depressing the lock button on the end of the control, and then
positioning the control as desired. When setting in flight the vernier should
always be used.
The mixture control should be set to “full rich” for take-off below 3,000 feet of
density altitude. Above 3,000 feet it is recommended the mixture be leaned to
the correct setting before take-off.
For more details of mixture setting requirements, see the section on Mixture
Setting in Normal Operations.
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Constant Speed Propellers (C172RG, R172/FR172)
Manifold Pressure and Throttle Setting
For engines that have a constant speed or variable pitch propeller fitted, the
amount of power obtained from the throttle setting is a combination of rpm and
manifold pressure.
When the engine is below governing speed the indication of power provided by
the throttle is a measure of engine rpm. The manifold pressure is below the
indicating scale, and the propeller is at the fine pitch stop, therefore increases
and decreases in engine speed are transmitted directly to the propeller. Once
the engine reaches governing speed then the throttle controls the manifold
pressure. Engine power is indicated by manifold pressure and the rpm is
maintained by the Constant Speed Unit (propeller governor).
When the engine is shut down the manifold pressure gauge will indicate ambient
pressure plus or minus a small margin for gauge errors. With the engine running
and full power applied, the manifold pressure should indicate the same pressure
before start, minus up to an inch, for losses in the intake manifold. Any greater
difference will indicate an engine problem.
Full Throttle Height
Although we are aware of power reduction with height with a fixed pitch
propeller, with a CSU we can see this directly by the manifold throttle
relationship. As we climb and the ambient pressure drops to maintain our climb
power setting in this case 23” we will have to progressively increase the throttle.
This will continue until we reach a point that the throttle is fully forward, so
termed “ full throttle height”. Climbing above this level will result in reducing
manifold pressure as we climb, until we reach the aircraft ceiling where the
power is just enough to maintain level flight.
Propeller Pitch Control
The propeller pitch is controlled by the constant speed unit (CSU), which
consists of the propeller pitch vernier control knob, propeller governor, linkages
and actuators. The CSU provides a propeller governing function by altering the
propeller blade angle (pitch) to maintain the selected rpm when there are
changes in aircraft attitude, speed or power setting.
The pilot sets the rpm on the pitch control in the cockpit, then once the power is
increased above the governing range and the selected rpm is reached, the prop
governor will increase or decrease the pitch to maintain the rpm. When below
the governing range the propeller reverts to normal governing operation
whereupon the throttle controls the propeller speed. This is normally occurs in
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CESSNA 172 TRAINING MANUAL
flight around 12” manifold pressure and is applicable for most ground
operations.
The governor controls flow of engine oil, boosted to high pressure by the
governing pump, to or from a piston in the propeller hub. Oil pressure acting on
the piston twists the blades towards high pitch (low propeller rpm). When oil
pressure to the piston in the propeller hub is relieved, centrifugal force, assisted
by an internal spring, twist the blades toward low pitch (high rpm).
The Propeller Control knob is
labeled PROP RPM, PUSH INC.
When the control knob is pushed
in, blade pitch will decrease,
giving a high rpm (“fine pitch”)
for maximum power. Inversely,
when the control knob is pulled
out, the blade pitch increases,
thereby decreasing rpm (“coarse
pitch”) providing less drag and
noise in the cruise . The propeller
control knob is equipped with a
vernier feature which allows slow
Illustration 5f Pitch Control
or fine rpm adjustment by
rotating the knob clockwise to
increase rpm, and counter-clockwise to decrease. To make rapid adjustment, the
button on the end of control knob shall be depressed and the control be
repositioned as desired. To avoid unnecessary stress on the engine this control
should not be used above the governing range in flight.
With the pitch control set to maximum and the throttle fully forward the engine
must develop the maximum rpm specified. This can be checked in a stationery
run-up if needed. Should full rpm not be developed after application of full
throttle for take-off, it is an indication that there is a possible fault in the CSU
unit, take-off should be discontinued.
The CSU function is checked during the engine run-up at 1700rpm. The
propeller pitch is selected momentarily to coarse and then back to full fine,
allowing rpm to drop and return. The rpm change should be not more than
approximately 300rpm, to avoid excessive loading on the engine. During the
cycle ensure as the rpm drops, manifold pressure increases and oil pressure
drops slightly, then all return to the previous setting after selection of full fine.
For the first flight of the day, the CSU cycle should be repeated two to three
times, not only to ensure functionality but also to cycle warm engine oil through
the CSU, ensuring proper lubrication and smooth operation before full power is
applied. The CSU may be sluggish initially in cold temperatures before the warm
oil has had a chance to circulate.
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Engine Gauges
Engine operation is monitored by the following instruments:
Q
Tachometer;
Q
Manifold Pressure gauge (C172RG and FR172/R172 models only);
Q
Oil pressure gauge and Oil temperature gauge;
Cylinder Head Temperature gauge;
Q
EGT indicator.
Tachometer
The engine-driven mechanical tachometer is
located near the upper centre portion of the
instrument panel. The instrument is calibrated in
increments of 100 rpm and indicates engine and
propeller speed. An hours meter inside the
tachometer dial records elapsed engine time and
runs at full speed only when the engine develops
full power. Hence total flight time, from the time
Illustration 5g RPM Gauge
the aircraft starts moving under it’s own power for
the purpose of flight, to the time it comes to a stop again (often referred to as
“chock to chock”), is usually higher than tacho. (tachometer) time.
Manifold Pressure Gauge (C172RG, R172/FR172)
The manifold pressure gauge is located on the lower left side of the pilot's
control column. The gauge is direct reading and indicates induction air manifold
pressure in inches of mercury. It has a normal operating range (green arc) of 15
to 25 inches of mercury.
To pre-flight check the manifold pressure gauge, ensure the indicator displays
within a small margin of ambient pressure in inches.
Fuel Flow Gauge ( C172RG, R172/FR172, C172Q, C172R,
C172S)
On the 180hp CSU models, the fuel flow is indicated opposite the manifold
pressure on the same gauge.
The C172Q has a separate fuel flow gauge on the right side of the instrument
panel.
The C172R and later have the fuel flow gauge displayed with the engine
instrumentation, on the left side of the main instrument panel, or for G1000
models, on the G1000 engine display.
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Oil Pressure and Temperature
Gauges
The oil pressure and temperature gauges are
located on the left bottom side of the
instrument panel. The normal operating range
on both gauges is marked by a green arc.
The temperature gauge is an electric resistance type device powered by the
electrical system. The pressure gauge is a mechanical direct reading device
based on a “Bordon Tube” design.
Indications vary from engine to engine, however any deviation from the green
range requires immediate action. This may include reduction in power,
increasing airspeed, richening mixture as applicable and contemplation of a
landing when possible.
Cylinder Head Temperature (CHT) Gauge
The Cylinder Head Temperature (CHT) indicator, if installed, is a more accurate
means of measuring the engine operating condition. It is a direct indication of
engine temperature compared with oil temperature which is surrounding the
engine and has inertia and damping effects. As this is one of the hottest part of
the engine probes are often prone
to failure, and may fail in a high
or low position. Indications should
be used in conjunction with the Oil
Temperature
and
Pressure
readings.
CHT gauges may often after
failure be replaced by alternative
gauges located in a different
position.
Always
scan
the
instrument layout before start
when flying a different aircraft.
Exhaust Gas Temperature
(EGT) Gauge
Illustration 5i EGT Gauge Installation
by O. Roud & D. Bruckert © 2006, This Edition 2014
The Exhaust Gas Temperature
(EGT) gauge, if installed, is
normally
located
near
the
tachometer. A thermocouple probe
in the muffler tailpipe measures
exhaust gas temperature and
transmits it to the indicator.
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Exhaust gas temperature varies with fuel-to-air ratio, power, and rpm. The
indicator is equipped with a manually positioned reference pointer.
G1000 Engine Instruments
On the G1000, all engine and system instrumentation is displayed on the left
side of the MFD (primary mode) or PFD (backup mode). The multi cylinder EGT
and CHT display can be seen by selecting 'LEAN' from the 'ENGINE' soft key
menu on the PFD or MFD.
When the MFD is in “back-up” mode, that is the PFD is displayed on both
screens, engine display pages are available on the left side of both screens. In
this configuration it is possible to select the primary engine page on one display,
and the “Lean” page, displaying CHT and EGT, on the secondary (MFD) display.
When using the MFD, engine instrumentation is only available on the MFD
screen. The EGT and CHT are displayed on the engine “Lean” page, accessed via
the soft keys at the bottom of the PFD and/or MFD.
The engine instruments are converted to digital data and displayed via Garmin's
Engine/Airframe unit the GEA 71. Any failure of
the G1000 or the GEA71 unit will result in a loss
of all engine instruments including the
tachometer and other primary engine control
instruments.
If a critical limit is exceeded, a red or yellow
engine annunciator will display, and the gauge
will display will change colour to yellow or red.
Engine instruments display a red cross when
failed.
Induction
Heat
Illustration 6a Carburettor
System
and
Carb.
The engine receives air through an intake in the
left opening in the nose cap. An induction
system air scoop is located in the aft vertical
baffle just behind the engine on the left side.
This scoop is covered by an air filter which
removes dust and other foreign matter from the
induction air.
In carburettor models, airflow passing through
the filter enters the inlet in the updraft-type
carburettor underneath the engine intake. The
air then is mixed with the fuel and ducted to the
engine cylinders through intake manifold tubes.
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The Carb Heat controls the selection of unfiltered hot air to the induction
system. The control operates a Bowden cable which terminates at a butterfly
valve in the carburettor air mixing box.
Air enters the mixing box from two sources:
Q
Normal cold induction air – through the intake mounted in the nose
and protected by a filter screen;
Q
Hot air intake, mounted on the starboard front shelf of the engine
cowling connected to a heat exchanger unit fitted to the engine
exhaust system.
The purpose of the hot air is to prevent the formation of ice in the induction line
of the engine. Ice formation of this type is recognized by a gradual or sharp
drop in the engine rpm and/or rough running. When icing is suspected, the
Carb. Heat control should be pulled into the fully out position. Confirmation of
the icing will be by a further drop (from the hot air), followed by an increase
when the ice is cleared.
If carburettor or intake ice is encountered or if the intake filter becomes blocked,
alternate heated air can be used by selecting the Carb Heat on. The Carb Heat
selector knob is mounted on the instrument panel to the left of the throttle. This
position provides a convenient reminder to consider the Carb Heat selection
when making power changes.
Carburettor ice is more prevalent at low power settings and recommended to be
used
whenever
operating below the
rpm
or
manifold
pressure green arc in
conditions likely for
formation (e.g. -10
and
+30
degrees
Celsius with relative
humidity of more than
50%), however pilots
should remember to
stow the Carb Heat
again on restoration
of
power
to
the
normal
operating
range.
Carb. Heat is normally
selected
on
when
reducing power for
the approach, then
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Illustration 6b Carburettor Ice
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CESSNA 172 TRAINING MANUAL
selected off again, when applying power for go around, or on short final when
committed to land.
Because the Carb Heat bypasses the air filter, it may also be used is the intake
filter becomes blocked. This will restore unfiltered hot air to the engine but with
a loss of performance and risk of damage from foreign matter, flight should be
continued under emergency conditions only to the nearest airfield or suitable
landing site.
Operation of the carb. heat should be always fully out or in, partial operation
may increase icing due to small heat raising temperature to the icing range. A
functioning test for the system should be carried out at 1700 rpm during engine
run up. With the selection of hot air, a positive drop in power should occur. Use
of full carburettor heat at full throttle during flight will result in a loss of
approximately 150rpm.
It should be remembered that heated air is obtained from an unfiltered outside
source, thus the system should not be used on the ground for prolonged time.
Dust inducted into the intake system of the engine is probably the greatest
single cause of early engine wear. Use of Carb Heat has also been attributed to
engine failures through ingesting foreign matter such as grass seeds and debris.
When operating under high dust conditions, the carburettor heat system should
not be used unless icing is suspected, and the induction air filter should be
serviced after the flight.
Note: Fuel injected engines do not have Carb. Heat.
Fuel Injection System (R172/FR172, C172R, C172S)
The latest model C172, and on the US Air Force F172, has a fuel injection
system. It is a low pressure, multi nozzle, continuous flow system which injects
raw fuel into the engine cylinder heads. The injection system is based on the
principle of measuring engine air inflow at the throttle venturi to control fuel
flow, proportional to the mixture setting. More or less air flow through the
throttle venturi will result in more or less fuel being delivered to the engine.
System components consist of the fuel/air control unit, the fuel distribution
valve (flow divider), injection nozzles (1 per cylinder total) and the fuel lines
connecting the components.
A description of the components is as follows:
Fuel/Air Control Unit - The fuel/air control unit, also known as the 'servo
regulator, is located on the underside of the engine and integrates the functions
of measuring airflow and controlling fuel flow. The control unit consists of an
airflow sensing system, a regulator section and a fuel metering section.
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Fuel Distribution Valve - The fuel distribution valve, also known as a 'spider'
or a flow divider, is located on top of the engine and serves to distribute fuel
evenly to the four cylinders once it has been regulated by the fuel/air control
unit. Also attached to the fuel distribution valve is a rigid line which feeds into a
pressure transducer. This transducer measures fuel pressure and translates that
reading into fuel flow at the cockpit indicator. Engines with a fuel injection
system will always have an fuel flow indicator in the cockpit.
Injection Nozzles - Each cylinder contains an injection nozzle, also known as
an air bleed nozzle or a fuel injector. This nozzle incorporates a calibrated jet
that determines, in conjunction with fuel pressure, the fuel flow entering each
cylinder. Fuel entering the nozzle is discharged through the jet into an ambient
air pressure chamber within the nozzle assembly. This nozzle assembly also
contains a calibrated opening which is vented to the atmosphere, and allows fuel
to be dispersed into the intake portion of the cylinder in an atomized, coneshaped pattern.
Fuel Pumps - Because the fuel injection system requires higher pressure than a
carburettor supply, fuel is delivered to the fuel injection system via an engine
driven fuel pump. An auxiliary electrical fuel pump is provided in case of a
failure of the engine driven pump, and for normal operations fulfils the priming
functions on a fuel injected engine. The auxiliary fuel pump is described further
in Fuel System, Normal Operations, and Emergency Operations sections.
Note: The C172RG and C172Q, with a larger 180hp engine capacity, is
one of the few models to have fuel pumps, the same as the fuel injected
system, but with a carburettor providing metered fuel-air to the engine.
Maximum Power Fuel Flow Settings
For the takeoff and maximum power on the R172K and FR172K, to obtain
the required power, it is
FUEL FLOW AT FULL THROTTLE 2600 rpm
essential to set the required
S.L. 16 GPH
fuel flow, as is required by all
4000 ft 14 GPH
larger fuel injected engines. For
8000 ft 12 GPH
12000
ft 10 GPH
this reason a placard must be
displayed on the instrument
panel.
The placard must contain the information displayed above.
Ignition System
The necessary high-tension electrical current for the spark plugs comes from
self-contained spark generation and distribution units called the magnetos. The
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magneto consists of a magnet that is rotated near a conductor which has a coil
of wire around it. The rotation of the magnet induces an electrical current to
flow in the coil.
The voltage is fed to each spark plug at
the appropriate time, causing a spark
to jump between the two electrodes.
This spark ignites the fuel/air mixture.
While the engine is running, the
magneto is a completely self-sufficient
source of electrical energy. The aircraft
is equipped with a dual ignition system
(two engine-driven magnetos, each
Magneto
controlling one of the two spark plugs
in each cylinder). A dual ignition
system is safer, providing backup in
Illustration 6c Magneto
event of failure of one ignition system,
and results in more even and efficient fuel combustion. The left magneto is
fitted on the left hand side of the engine, as viewed from the pilot’s seat, and
fires the plugs fitted into the top of the left cylinders and the bottom of the right
cylinders, the right magneto is on the right hand side and fires the opposite
plugs (although the ignition selector switch is fitted in reverse - R then L). The
dual system has an added bonus of being able to isolate left and right parts for
easy plug and magneto fault finding during engine run up.
Ignition and starter operation is controlled by a rotary type switch located on the
left bottom side of the instrument panel. The switch is labelled clockwise: OFF,
R, L, BOTH and START. When the ignition switch is placed on L (left) the left
magneto and left ignition circuit is working and the right ignition circuit is off
and vice versa. The engine should be operated on both magnetos (BOTH
position) in all situations apart from magneto checks and in an emergency.
When the switch is rotated to the spring-loaded START position (with master
switch in the ON position), the starter is
energized and the starter will crank the
engine. When the switch is released, it will
automatically return to the BOTH position.
Note: Early models, C172C, 1962 and earlier
have two independent ignition switches for the
left and right magnetos, and a pull starter for
starting.
Dead Cut and Live Mag. Check
It is important to remember if the ignition is
live, the engine may be started by moving the
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Illustration 6d Magneto Switch
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CESSNA 172 TRAINING MANUAL
propeller, even though the master switch is OFF. The magneto does not require
outside source of electrical energy.
Placing the ignition switch to OFF position grounds the primary winding of the
magneto system so that it no longer supplies electrical power. With a loose or
broken wire, or some other fault, switching the ignition to OFF may not ground
both magnetos.
To prevent this situation, just before shutting an engine down, a “dead-cut” of
the ignition system should be made.
The dead-cut check is made by switching the ignition momentarily to OFF and a
sudden loss of power should be apparent. This is carried out most effectively
from R, not from Both, to prevent inadvertent sticking in OFF.
On start up, a live mag. check is performed, to ensure both magnetos are
working before taxi. This is not a system function check detailed below, as the
engine is still cold and plugs may be fouled, rather just a check to ensure both
magnetos are working by switching from Both to L, then R, and back to Both,
noting a small drop from Both in L and R positions. A dead-cut check may be
carried out at the same time.
The engine will run on just one magneto, but the burning is less efficient, not as
smooth as on two, and there is a slight drop in rpm. The magneto check to
confirm both magnetos and plugs are operational should be made at 1700 rpm
or 1800 rpm depending on model.
Magneto and plug check:
Q
Move ignition switch to R position, allow to stabilise and note the
rpm;
Q
Then move switch back to BOTH to clear the other set of plugs;
Q
Repeat for the L position and return to BOTH position.
The maximum limit of the rpm drop is 125, 150 or 175 rpm depending on the
model. The rpm drop should not exceed the maximum on either magneto, and
should not have a difference greater than 50 rpm between each magneto drop.
An absence of rpm drop may be an indication of faulty grounding of one side of
the ignition system, a disconnected ground lead at the magneto, or possibly the
magneto timing is set too far in advance. An absence of rpm drop on one
magneto will usually mean the other magneto is dead, and selecting it will result
in an engine 'dead' cut.
An excessive drop or excessive differential normally indicates a faulty magneto.
Fouled spark plugs (lead deposits on the spark plug preventing ignition) are
indicated by rough running usually combined with a large drop in rpm (i.e. one
or more cylinders not firing). This is due to one of the two plugs becoming
fouled, normally the lower plug. Spark plug fouling, if not excessive, may be
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burnt off. Run the engine at a correct or slightly lean mixture setting and a high
power setting (+/-2000rpm) for a few minutes, caution engine temperatures
and surrounds. Where spark plug fouling is mild, just leaning the mixture will
improve the burning efficiency on one magneto, and can bring the drop back to
acceptable limits.
Engine Lubrication
A wet sump, pressure lubricated oil system is fitted. Oil is supplied from a sump
on the bottom of the engine. A wet sump engine has a sump attached to it in
which the oil is stored. The capacity of the sump is from 6 to 12 imperial quarts
depending on the engine type.
Oil is drawn from the sump through the engine-driven oil pump to a
thermostatically controlled bypass valve. If the oil is cold, the bypass valve
allows the oil to bypass the oil cooler and flow directly to the oil filter. If the oil is
hot, the oil is routed to the engine oil cooler mounted on the left forward side of
the engine and then to the filter. The filtered oil then enters a pressure relief
valve which regulates engine oil pressure by allowing excessive oil to return to
the sump, while the balance of the pressure oil is circulated to the various
engine parts for engine lubrication and cooling, Oil is returned by gravity to the
engine sump.
Because oil viscosity changes with temperature and due to the nature of this
system, there will be a small change in the pressure with changes in operating
temperatures, the warmer the temperature the lower the pressure. It should be
noted that any large increases in temperature or decreases in pressure, or
deviation from normal operating (green) range are an indication of possible
malfunction. Discontinuation of the flight or landing at the nearest suitable
location should be contemplated.
Oil temperature and pressure gauges are fitted for monitoring engine condition,
normally on the lower part of the instrument panel (see more under Oil
Temperature and Pressure Gauges earlier in this section). If normal oil pressure
is not indicated within 30 seconds of starting, the engine should be shut down
immediately. This time is not only a maximum, but it should also be taken
relatively. For the oil pressure to only begin rising after 30 seconds would only
occur in extreme cold weather starting. In all normal temperatures, one would
expect to see normal temperatures within around 3 to 5 seconds of start-up. If
abnormal oil pressure is suspected, it is best to err on the safe side and shut
down as soon as possible to prevent engine damage.
It is also important to ensure that rpm is kept to a minimum during initial
starting prior to oil pressure being fully operational.
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The oil tank dipstick is fastened to the oil filler cap. Access to the filler cap is
through the inspection panel on the right side of the engine. Make sure that the
filler cap is firmly on. Over turning may result in damage to the cap or difficulty
in loosening, under turning may result in loss of oil or cap during flight.
Illustration 7a Oil Distribution
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Access to the filler cap is through the inspection panel on the right side of the
engine. Make sure that the filler cap is firmly on. Over turning may result in
damage to the cap or difficulty in loosening, under turning may result in loss of
oil or cap during flight.
Oil dipstick on older models
Oil dipstick on newer models
Illustration 7b Oil Dipstick and Filler Cap
Oil capacities differ throughout the series, depending on the engine type. As a
rule, oil should be added if the level is below 1 quart from the minimum level. To
minimize loss of oil through the breather, another rule of thumb is to ensure the
oil is not more than 2 quarts above the minimum for normal flights of less than
three hours. For extended flights, it may be desired to fill the oil up to the
maximum quantity permitted.
Note: Check the POH on your aircraft for the correct oil capacity for your
aircraft, this is normally found in the Servicing and Maintenance section.
Cooling System
The engine cooling system is designed to keep the engine temperature within
those limits designed by the manufacturer.
Engine temperatures are kept within acceptable limits by
Q
The oil that circulates within the engine;
Q
The air cooling system that circulates fresh air around the engine
compartment.
The engine is air-cooled by exposing the cylinders and their cooling fins to the
airflow. Air for engine cooling enters through two openings in the front of the
engine cowling. The cooling air is directed around the cylinders and other areas
of the engine by baffling, and is then exhausted through an opening at the
bottom aft edge of the cowling. No manual cooling system control is provided.
Air cooling is least effective at high power and low airspeed, for instance on
take-off and climb. At high airspeed and low power, for instance on descent, the
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cooling might be too effective. It is therefore important to monitor the cylinderhead temperature gauge throughout the flight, and also on the ground when aircooling will be poor.
If excessive temperatures are noted in flight,cooling of the engine can
improved by:
Q
En-richening the mixture (extra fuel has a cooling effect in
cylinders and combustion temperatures are lower);
Q
Reducing the engine power;
Q
Increasing the airspeed (e.g. level off or establish in a descent);
Q
Opening cowl flaps (if fitted) see more below.
The propeller spinner in addition to streamlining and balance is a director for
cooling air, and so the aeroplane should generally not be operated without
spinner.
be
the
the
the
Illustration 7c Cooling Air Flow
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Cowl Flaps (C172RG and FR172/F172 Models)
Cowl flaps are provided to aid in controlling the engine temperature. The engine
exhaust protrudes through a cut-out in the aft portion of the right cowl flap. The
cooling air is directed from the opening at the front of the cowling, around the
cylinders and other areas of the engine by baffling, and is then exhausted
through cowl flaps on the lower aft edge of the cowling.
The
two
cowl
flaps
are
mechanically operated from the
cabin by means of a single cowl
flap lever on the right side of the
control pedestal. The lever may
be positioned from fully OPEN
(down) to fully CLOSED (up) or
positioned at an intermediate
setting.
This is accomplished by first
moving the lever to the right to
clear the detent which holds it in
position, then moving the lever
up or down to the desired
position.
Illustration 7d Cowl Flaps
Herewith some guidelines for standard operations with cowl flaps.
Q
Before starting the engine, and throughout takeoff and high power climb
operation, the cowl flaps should be in the OPEN position for maximum
cooling.
Q
While in cruise flight, cowl flaps should be adjusted partially or fully
CLOSED to keep the cylinder head temperature at a normal operating
position, approximately two-thirds of the normal operating range (green
arc) for most normally aspirated engines.
Q
During extended descent, or low power operation the cowl flaps should
be completely closed unless very high ambient or high engine operating
temperatures are observed.
Q
Cowl flaps should be OPENED prior to landing as a preparation for a go
around, and should always be OPEN after landing and for all ground
operations due to the much lower amount of cooling air flow over the
cylinders.
Q
In very hot or very cold temperatures, and for certain types of engine,
this may sometimes differ, consult your POH or a flight instructor in the
area.
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Fuel System
All models of C172 have a gravity flow fuel system feeding from the fuel tanks
or integral bays in the high wing.
There are two integral aluminum tanks (one per wing) in the standard and longrange systems. There is an integral fuel bay area in each wing in the extended
range system and in the C172R, 1996 and later models.
The integral bay is a wet wing system, more efficiently utilising the wing
structure as a tank. The earlier models have an integral tank – that is, a
separate tank, which is 'integrated' into the wing.
From the wing, fuel flows to a three or four-position selector valve, through a
firewall-mounted fuel strainer.
Depending upon selector valve handle position, fuel is directed from one or both
tanks or to the engine, or flow can be shut off completely.
From the fuel strainer the fuel either flows directly to the carburetor and engine
primer, or to the engine-driven fuel pump and the auxiliary electric fuel pump,
where fuel under pressure is then delivered to the carburettor or to the fuel
control unit.
Note: The fuel injected models and the C172Q and C172RG have a fuel pump to
increase the pressure of fuel at the manifold for the increased demand of the
fuel injection and the higher powered engine.
From the carburettor, mixed fuel and air flows to the cylinders through the
intake manifold. For fuel injected models, metered fuel flows from the fuel
control unit to the fuel injector nozzles.
Fuel systems for the different models are shown in the schematic diagrams on
the following pages. Representative diagrams of the three main systems are
shown, that is for the standard fuel system, the C172RG/C172Q, and the fuel
injected models.
Note: fuel systems can differ, even between the same model.
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Standard Fuel System Schematic
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Fuel System Schematic C172RG
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Fuel System Schematic Fuel Injected Models
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The following summarises the approximate* total and usable fuel on the various
models of C172:
Q
C172 - 42 total, 37 usable US gallons (159/140 litres) standard fuel
tanks;
Q
C172A, B - 42 total, 39 usable US gallons (159/147 litres) standard fuel
tanks;
Q
C172C to H - 39 total, 36 usable US gallons (147/136 litres) standard
fuel tanks;
Q
C172I, K, L, M - 42 total, 38 usable US gallons (159/144 litres) standard
fuel tanks;
Q
C172I, K, L, M - 52 total, 48 usable US gallons (201/186 litres) long
range fuel tanks;
Q
C172N,P - 43 total, 40 usable US gallons (163/151 litres) standard fuel
tanks;
Q
C172N,P - 42 total, 40 usable US gallons (159/151 litres) long range fuel
tanks;
Q
C172P - 68 total, 62 usable US gallons (257/234 litres) wet wing fuel
tanks;
Q
C172Q - 54 total, 50 usable US gallons (204/189 litres) standard fuel
tanks;
Q
C172R,S - 56 total, 53 usable US gallons (212/200 litres) standard fuel
tanks;
Q
P172 - 52 total, 41.5 usable US gallons (197/158 litres) standard fuel
tanks;
FR172,R172K - 52 total, 49 usable US gallons (197/185 litres) standard
fuel tanks;
Q
FR172,R172K - 68 total, 66 usable US gallons (257/250 litres) long range
tanks;
C172RG - 66 total, 62 usable US gallons (250/235 litres) standard fuel
tanks;
*These figures are approximate as variations exist between type certification
information, and maintenance manuals, and more importantly, it should be
remembered, individual manufacturing tolerances, tanks can be modified by
STCs, and density changes will give rise to slight variations in tank capacity. The
usable tank capacity should be placarded on the fuel selector of the model you
are flying. Check the POH for fuel system on particular aircraft you are going to
fly for the correct quantities and operational requirements.
The amount of fuel we can put into fuel tanks is limited by the volume of the
tanks, and therefore usable fuel is always provided in volume, such as gallons
and litres.
However, the carburettor and engine are only sensitive to the mass of fuel, and
not to the volume. The engine will consume a certain mass (lbs or kgs) of fuel
per hour.
Fuel has a wide variation in specific gravity (weight of fuel per volume) mostly
depending on temperature and type of fuel. Therefore, variations in specific
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gravity of fuel can have a significant effect on the mass of fuel in the tanks and
therefore the range and endurance. For practical purposes the specific gravity of
Avgas is taken as 0.72 kgs/lt.
Fuel Selector Valve
The fuel valve is located on the floor
of the cockpit between the pilot and
co-pilot seats. The selector valve on
most models has four positions,
labeled:
BOTH ON, RIGHT, LEFT, and BOTH
OFF.
Models C172R and later have a
three position selector with LEFT,
RIGHT
and
BOTH.
There
is
additionally a fuel shut off valve
which, when pulled fully out, stops
the fuel flow, thus functioning as an
OFF position.
Illustration 8a Fuel Selector

The BOTH position must be selected for takeoff and landing, this
requirement is also a mandatory placard on the fuel selector.

In all models up to C172K fitted with the original fuel system, operating in
the BOTH position at high density altitudes may lead to fuel vapourisation,
resulting in loss of power or engine failure. In models where this applies fuel
must be selected to LEFT or RIGHT once above 5000ft in the cruise. This
information, if not available in the POH, is published in FAA AD 72-07-02.
For all other models, if vaporisation is suspected, provided there is fuel
available, it is recommended to try selecting an alternative tank, as the
alternative fuel routing may fix the problem.
The reason for this issue and the solution, is due to the excess fuel return line
and the fuel reservoir routing, which differs throughout the C172 series.
Note: For fuel injected models, if experiencing an engine failure or suspected
vapourisation, the fuel pump must be switched on first.

When leaving the aircraft, and when refueling, the fuel selector should be
selected to left or right to prevent cross draining through the fuel balance tube
and vent lines. Many pilots have come back to their aircraft, after parking
overnight, to find they've lost a couple of hours fuel out of the vent line – be
warned!
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Fuel Measuring and Indication
Fuel quantity is measured by two float-type
quantity transmitters (one in each tank), and
indicated by two electrically-operated fuel
quantity indicators on the left portion of the
instrument panel.
The full position of float produces a minimum
Illustration 8b Fuel Gauges
resistance through the transmitter, permitting
maximum current flow through the fuel quantity indicator and maximum pointer
deflection.
As fuel level is lowered, resistance in the transmitter is increased, producing a
decreased current flow and a smaller pointer deflection.
An empty tank, indicated by a red line and letter E, means there is
approximately 1 to 3 gallons remaining in the tank as unusable fuel.
The float gauge will indicate variations with changes in the position of fuel in the
tanks and cannot be relied upon for accurate reading during skids, slips, or
unusual attitudes.

Considering the nature of the system, takeoff is not recommended with less
than 1 hour total fuel remaining. Fuel quantity should always be confirmed by
use of a dipstick during the pre-flight inspection and on intermediate stops enroute.

If operating with less than ¼ tanks, avoid any prolonged turns, skids, or
extreme pitch attitudes, which would allow the fuel drain point in the tank to be
deprived of fuel, leading to fuel starvation and possible engine failure.
Low Fuel Warning System
The C172R and later models have a low fuel warning system, which annunciates
when the fuel is below 5 gallons in each tank.
The low fuel warning system may illuminate during slips/skids, large attitude
changes or acceleration/deceleration when fuel is between 5 gallons and 10
gallons each side.
When tanks are full, the fuel sensors occasionally cut out from exceeding the
upper limits of the gauge. When this happens on conventional models, the low
fuel annunciator will illuminate, and the fuel gauge will read zero. For, G1000
models, the fuel gauge will show a red cross, indicating the gauge has failed,
but no warning will illuminate. This usually only occurs when within 5 gallons of
full tanks, and is intermittent, causing the warning to cycle on and off
periodically.
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Fuel Venting
Fuel system venting is essential to system
operation and is necessary to allow normal
fuel flow and relieve pressure as fuel is
used. Blockage of the venting system will
result in a decreasing fuel flow and
eventual engine stoppage.
A vent line is installed in the outboard end
of the left fuel cell and extends overboard
Illustration 8c Fuel Vent
down through the lower wing skin. The inboard end
of the vent line extends into the fuel tank, then forward and slightly upward. A
vent valve is installed on the inboard end of the vent line inside the fuel tank,
and a crossover vent line connects the two tanks for positive ventilation.
The vent line opens to the highest part of the tank, therefore it is normal, when
the tanks are full, to see a small amount of overflow fuel leaking through the
fuel vent.
In all C172s, both wing fuel caps must be vented, according to the Airworthy
Directive AD 79-10-14 R1, 30 th May 1988. As indicated above, only the left wing
contains a forward facing vent, which is pressurised by the dynamic pressure of
the relative airflow. The right wing is pressurised via a balance tube, and the
vent in the fuel cap.
 Despite modifications to the balance tube in attempt to rectify the situation,
because of the design of the fuel venting, most Cessna's will burn fuel from the
left tank first. This is considered largely unavoidable, and, careful fuel
monitoring and balancing in flight is the only real solution to the problem.
If uneven feeding is significant, the fuel may be balanced by selecting the fuller
tank. Note, operation on one tank in the C172 is permitted only in level flight.
 Caution, when changing fuel tanks (from both to left or right, or returning to
both), always ensure there is continued fuel supply, be ready to change tanks
back in the event of an engine failure after changing to a new tank.
If uneven feeding becomes severe the situation should be checked by a
maintenance organisation, as there is possibly a blockage in the fuel lines,
vents, or balance tube.
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Fuel Drains
The fuel system is equipped with drain
valves to provide a means for the
examination of fuel in the system for
contamination and grade. The system should
be examined before the first flight of every
day and after each refuelling, by using the
sampler cup to drain fuel from the drain
points on the wing tanks and sump.
Illustration 8d Fuel Sampling
Water may be introduced by condensation or from
heavy rain, and may be introduced directly into the tanks or from the refuelling
point.
Water in fuel is most likely to develop overnight, in humid conditions, when
tanks are partially full. There is usually a drop in air temperature overnight and,
if the tank is not full, the fuel tanks’ walls will become cold and there will be a
lot more condensation than if the tanks were full of fuel.
The water, as it is heavier than fuel, will accumulate at the bottom of the fuel
tanks.
If water is found in the tank, fuel should be drained until all the water has been
removed, and wings should be rocked to allow any other water to gravitate to
the fuel strainer drain valve.
If any sediment or debris are found in the fuel system, maintenance should be
consulted. Rubber particles can be indication of a failing O-ring seal, and an
impending fuel leak.
Most models have one under wing drain on each tank and one fuel strainer drain
valve in the lower engine bay, draining the low point of the fuel system. Some
models, for example the C172R and C172S have ten under wing drains (five on
each side), and three sump drains installed, for the fuel selector, fuel reservoir,
and fuel strainer.
On most models, the fuel strainer drain valve control is located adjacent to the
oil dipstick, and is accessible through the oil dipstick door. Late models (C172R
and later) have spring loaded sump drains, the same as those on the wing.
 Where the sump drain is a pull lever, it is of vital importance to ensure it is
firmly closed again after draining.
Ensure all fuel drains are checked during the pre-flight inspection.
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Priming System
A manual primer is fitted to all models without
a fuel pump. The manual priming system
consists of a manually operated pump located
on left bottom corner of the instrument panel,
and distribution lines to the engine cylinders
or intake manifold.
The manual primer draws its fuel from the fuel
strainer and injects it directly into the engine.
Depending on model, the injection point may
be the intake manifold, or the intake port of
Illustration 8e Manual Primer
the cylinder.
The primer differs over the series, and may be
a standard one cylinder primer, or an optional three cylinder primer, or in the
F172, with a O-300-D Continental engine, the primer directs fuel into the intake
manifold, just above the carburettor. The three cylinder optional primer directs
fuel to cylinders 1, 2 and 4.
A multi-cylinder manual primer, or a primer which primes the full intake
manifold, if not fitted, it is highly recommended for improved cold weather
starting.
Priming the engine is normally required when starting a cold engine, when the
fuel in the carburettor is reluctant to vaporize. One to three pumps of the primer
is recommended depending on the temperature and should be carried out
immediately prior to starting. If priming is carried out too early the fuel is
ineffective in the start cycle, but effective in washing oil from the cylinder walls
and causing additional frictional wear on start.
The primer should be locked when the engine is running to avoid excessive fuel
being drawn through the priming line into the cylinders, which could cause an
engine failure from the fuel/air mixture becoming too rich.
Although priming may be achieved by operation of the throttle, the primer is a
more effective method as fuel enters directly into the cylinder, and it is the
recommended method specified in the pilots operating handbook.
The fuel injected models (FR172, R172, C172R, and C172S), and the 180hp
Cutlass (C172Q, C172RG), use the throttle and auxiliary fuel pump for priming.
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Auxiliary Fuel Pump
Fuel-injected Models (FR172, R172, C172R, C172S), and Cutlass (C172Q,
C172RG)
An electrically driven auxiliary fuel pump is mounted on the firewall and is
connected in parallel with the fuel flow of the primary engine driven pump.
The auxiliary fuel pump switch located adjacent to the master switch is used to
select the pump on or off. The auxiliary fuel pump is provided as a back-up to
the engine driven pump. The engine driven pump has no pilot controls, and runs
automatically without the pilot being aware of it, unless there is a failure.
The auxiliary fuel pump also serves the function of primer in fuel injected
models, and is used for starting, as directed in the POH.
The C172Q and C172RG have both an auxiliary fuel pump and an engine driven
pump, functioning in the same way as detailed above. Both connect to the
carburettor intake. The purpose of the fuel pumps are to ensure sufficient
pressure with the larger power on the 180hp engine.
Auxiliary Fuel Pump Operation
In cruise and descent, and at low power operations, gravity may be sufficient for
sustained engine operation without the fuel pump, and a failure may not be
noticed until higher power is selected again.
In the climb, and high power operations, if the engine driven pump fails there
will be a sudden loss of power, preceded by a drop in fuel pressure. The auxiliary
fuel pump should be switched on, and the flight terminated as soon as possible.
Any time there are fuel flow fluctuations (while sufficient fuel exists in the
tanks), the auxiliary pump should be used.
In hot temperatures, or at high engine operating temperatures, fuel
vapourisation can cause fuel fluctuations, resulting in rough running or engine
failure. The auxiliary fuel pump can be used to stabilise vaporisation and restore
engine operation. Refer to emergency operations, and to the POH of your
aircraft for more information on this.
Although all models with an auxiliary fuel pump use it for priming, the methods
differ slightly, refer to the POH of the model you are flying. Some additional
guidance is provided in the Normal Operations section of this book.
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Electrical System
Electrical energy for the aircraft is supplied by a 14 or 28 volt, direct-current,
single wire, negative ground electrical system.
The system is either:
For models
Q
Q
Q
before 1967:
14 Volt system;
20, 35, or 50 amp generator;
12 volt battery with 25 or 33 amp-hours capacity.
For models
Q
Q
Q
after 1967, and before 1978:
14 Volt system;
52 or 60 amp alternator;
12 volt battery with a 25 or 33 amp-hours capacity.
For models
Q
Q
Q
1979 and later:
28 volt system;
60 amp alternator;
24 volt battery with 17, 12.75 or optional 15.5 amp-hour capacity.
Additionally for models equipped with G1000 avionics:
Q
24 volt standby battery (for operation of the G1000 essential bus
only).
Battery
The 12 volt for models 1978 or earlier, or 24 volt lead-acid battery supplies
power for starting and furnishes a reserve source of power in the event of
alternator failure. The battery is mounted on the left forward side of the firewall
(see picture on the next page). Only the P172, C172RG, and R172 models.
which are based on the C175 airframe, have the battery mounted on the left
hand side of the aft fuselage behind the baggage compartment wall.
The battery capacity will be either:
Q
12 Volt with 25 or 33 amp-hour capacity (1978 and earlier);
Q
24 Volts, with 17 or 12.75 standard, 15.5 optional capacity (1979
and later).
The amp-hour is the capacity of the battery to provide a current for a certain
time. A 14 amp-hour battery is capable of steadily supplying a current of 1 amp
for 14 hours and 7 amp for 2 hours and so on. Amp hours is very useful where
an accurate ammeter is provided, whereupon following an alternator failure, it is
easy to determine the approximate length of useful battery time.
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Standby Battery (G1000 Equipped Aircraft)
With G1000 equipped aircraft, a small standby battery is installed for the
purpose of maintaining electrical power to the G1000 essential bus. This powers
the primary flight display (PFD) and essential avionics and engine instruments in
back up mode only, in case of an electrical supply fault or failure of the main
battery circuit.
The G1000 essential bus provides power to the PFD, AHRS, ADC, COM1, NAV1,
Engine and Airframe Unit, and standby instrument lights.
Illustration 9a Typical battery Installation
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The 24 volt standby battery, provides approximately 30 minutes power for
operation of the G1000 in back up mode.
The standby battery will automatically take over electrical supply when the main
battery falls below approximately 20 volts. It may also be manually selected
after failure of the alternator, providing automatic load shedding and conserving
main battery power, with full availability of electrical equipment, for use during
more critical stages of flight.
Electrical Power Supply
The aircraft is fitted with either a generator or alternator for generating electrical
power during flight and maintaining the battery charge.
The charging system capacity (14 or 28 volt), is the output from the generator
or alternator after voltage regulation. This is always slightly more than the
battery (12 or 24 volt) to ensure continuous charge to the battery when using
the electrical system in normal operations.
Models manufactured in 1966 or earlier were fitted with a 20, 35 or 50 amp
generator. Models produced in 1967 or later were fitted with a 52 or 60 amp
engine-driven alternator. The electrical supply from the alternator is rectified
and controlled by a voltage regulator/alternator control unit.
External Power Receptacle
An external power receptacle is offered as an option in all models, to provide a
simple method of connecting an alternative electrical power supply to the
battery during stationary ground operations. External power may be used to
supplement battery power for starting, or for prolonged operation of electrical
equipment on the ground without the engine running.
Electrical Equipment
The following standard equipment on the Cessna 172 requires electrical power
for operation (there may be additional optional equipment which uses electrical
power):
Q
Fuel quantity indicators;
Q
All internal and external lights and beacon, including warning
lights;
Q
Pitot heat;
Q
Wing flaps;
Q
Landing gear main extension and retraction system (RG model
only);
Q
Starter motor;
Q
Cylinder head temperature gauge and Exhaust Gas Temperature
gauge (where fitted);
Q
All radio and radio-navigation equipment.
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System Protection and Distribution
On most models, electrical power for electrical equipment and electronic
installations is supplied through the split bus bar. The bus bar is interconnected
by a wire and attached to the circuit breakers on the lower, centre of the
instrument panel. Some models prior to 1969, and all models prior to 1967 were
equipped with a single bus bar.
Circuit breakers or fuses are provided to protect electrical equipment from
current overload. If there is an electrical overload or short-circuit, a circuit
breaker (CB) will pop out and break the circuit so that no current can flow
through it.
It is normal procedure (provided there is no smell or other sign of burning or
overheating), to reset a circuit breaker once. To reset a circuit breaker, After
allowing a cooling period of two to three minutes, push it back in once only. Do
not hold the CB in or force it back in, as
this can cause damage to electrical
equipment or fire.
Most of the electrical circuits in the
aeroplane are protected by “push-toreset” type circuit breakers. However,
alternator output and some others are
protected by a “pull-off” type circuit
breaker to allow for voluntary isolation
in case of a malfunction.
Electrical
circuits
which
are
not
protected by circuit breakers are the
Illustration 9b Circuit Breakers
battery contactor closing circuit (for
external power), clock circuit, and flight hour recorder circuit.
These circuits are protected by fuses mounted adjacent to the battery and are
sometimes termed “hot wired” or “hot bus” connections because the connection
is not controlled by the battery master switch.
The master switch controls the operation of the battery and alternation system.
For models after 1970, the switch is an interlocking split rocker type with the
battery mode on the right hand side and the alternator mode on the left hand
side. This arrangement allows the battery to be on line without the alternator,
however, operation of the alternator without the battery on the line is not
possible.
The switch is labelled BAT and ALT and is located on the left-hand side of the
instrument panel.
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If the battery power drops too low, (from
operating without the alternator, or from
standing for a long time) the battery
contactor will open, and remove power
from the alternator field. This will prevent
the alternator operating again. It is
important to remember if you are starting
an aeroplane with ground power because
of a flat battery, make sure the alternator
is operating after start.
Earlier models have a one position pull
type switch.
The ammeter, located on the lower left
side of the instrument panel, indicates the
flow of current, in amperes, from the
alternator to the battery or from the
battery to the aircraft electrical system.
When the engine is operating and the
master switch is ON, the ammeter
Illustration 9c Master Switch and Ammeter
indicates the charging rate applied to the
battery.
When the ammeter needle is deflected right of center, the current flows into the
battery and indicates the battery charge rate.
When the ammeter needle is deflected left of center, the current flows from the
battery the battery and the battery is therefore discharging.
With battery switch ON and no alternator output, the ammeter will indicate a
discharge from the battery, because the battery is providing current for the
electrical circuits that are switched on.
If the alternator is ON, but incapable of supplying sufficient power to the
electrical circuits, the battery must make up the balance and there will be some
flow of current from the battery. The ammeter will show a discharge. In this
case, the load on the electrical system should be reduced by switching off
unnecessary electrical equipment until the ammeter
indicates a charge.
Indication of charge from the system to the battery
more than temporarily may indicate more serious
problems and should be checked out immediately.
The aircraft is equipped with a voltage warning and
protection system consisting of an under-volt
sensor and an over-voltage cutout, with a red
warning light near the ammeter.
Illustration 9d Low Voltage Light
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For models 1977 and earlier, this is labeled HIGH VOLTAGE, for models 1978
and later it is more suitably labeled “LOW VOLTAGE”.
In both cases, when an over-voltage condition occurs the over-voltage sensor
turns off the alternator or generator system and the red warning light comes on
and the ammeter will show a discharge, indicating to the pilot that the battery is
supplying all electrical power.
Turn off both sections of the master switch to recycle the over-voltage sensor. If
the over-voltage condition was transient, the light will remain extinguished. and
no further action is necessary. If, after resetting, the light illuminates again, a
malfunction in the electrical supply system has occurred. The flight should be
terminated as soon as practical, and provisions made for completion of the
remainder of the flight with electrical supply from the battery only.
The over-voltage warning light may be tested by momentarily turning OFF the
ALT portion of the master switch and confirming that the light illuminates.
Illumination of the low-voltage light may occur during low rpm conditions with
an electrical load on the system, such as during the taxi at low rpm. Under
these conditions, the light will go out at higher rpm, and the master switch need
not be recycled since an over-voltage condition has not occurred to de-activate
the alternator.
Note, it is often deemed impossible to have a sustained over-voltage condition,
since the protection mechanisms should prevent such an occurrence by
disconnecting the faulty circuit. For this reason generally nothing is written
about handling a sustained over-voltage. Although it is unlikely, experience
dictates that it is possible, either due to a failure or faulty set point in the overvolt protection, or because a severe electrical spike causes the protection
mechanism to hard-wire. If this should occur, the primary indication will be the
ammeter. It is important to remove the over-voltage source by disconnecting
the generator/alternator immediately, thereafter continue flight as described
above on battery power only.
Electrical schematic diagrams can be seen on the following pages.
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Electrical System Schematic Conventional Aircraft
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G1000 Electrical Distribution Schematic
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Flight Instruments and Associated Systems
The aircraft is normally equipped with the following standard flight instruments:
Q
Q
Q
Q
Q
Q
Attitude Indicator (requires vacuum system for operation and it
gives a visual indication of flight attitude. A knob at the bottom of
the instrument is provided for in-flight adjustment of the miniature
aeroplane to the horizon bar);
Directional Indicator (requires vacuum system for operation and it
displays aeroplane heading on a compass card. A knob on the lower
left edge of the instrument is used to adjust the compass card to
correct for any precession);
Airspeed Indicator (requires dynamic and static pressure and is
calibrated in knots or miles per hour. The instrument has limitation
marking in form of white, green and yellow arcs and a red line);
Altimeter (requires static pressure and depicts aeroplane altitude in
feet. A knob near the lower left edge of the instrument provides
adjustment of the barometric scale to the current altimeter setting –
QNH/QNE/QFE);
Vertical Speed Indicator (requires static pressure and it depicts
aeroplane rate of climb or descent in feet per minute).
Turn and Slip Indicator (requires electric power for rate of turn
indication, gravity for slip indication)
For G1000 equipped aircraft all the above flight instruments are contained on
the primary flight display.
Conventional vs G1000 Flight Instruments
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Vacuum System
Suction is necessary to operate
the
main
gyro
instruments,
consisting of the attitude indicator
and directional indicator.
A suction gauge is fitted on the
instrument panel and indicates
suction at the gyros.
Suction is normally provided by a
dry-type, engine-driven, vacuum
pump. A suction relief valve, to
control
system
pressure,
is
connected between the pump inlet
and the instruments.
Illustration 10a Vacuum Pump
All models prior to 1962 and standard models prior to 1968 may be fitted with a
single or dual venturi system for generating suction pressure to operate the
suction driven gyro instruments.
The venturi system relies on airspeed to work, so, note, no suction pressure will
indicate during the engine run-up.
Illustration 10b Vacuum Venturi
One advantage is that because of it's simplicity, providing there is airspeed, it is
very reliable, failure can only result from blockage or structural damage or a
pipe connection failure, there are no moving parts.
A suction range of 4.6 to 5.4 inches of mercury below atmospheric pressure is
acceptable.
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If the vacuum pressure is too low, the airflow will be reduced, the gyro’s rotor
will not run at the required speed, and the gyro instruments will be unreliable.
If the pressure is too high, the gyro rotors speed will be too fast and the gyro
may be damaged.
Illustration 10c Vacuum Driven Gyro Instruments
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
When the vacuum pressure is too low, the gyro will not remain rigid, and the
reference (attitude, or direction) will indicate an error. The gyro may completely
topple, or, the error can be subtle and barely noticeable. Subtle gyro wander, in
either attitude or direction can leading to serious problems when flying under
instrument conditions. Ensure the gyro attitude indicator is always crossreferenced with performance instruments, and the direction indicator is regularly
checked against the compass.
From mid 1983 a low vacuum warning light was fitted, which illuminates when
the vacuum pressure drops below 3 inches. Later models, from 1996 on, have a
Low Vac (low vacuum) annunciator.
Pitot-Static System
The pitot-static system supplies dynamic air pressure to the airspeed indicator
and static air pressure to the airspeed indicator, vertical speed indicator and
altimeter.
The system is composed of a pitot tube mounted on the lower surface of the left
wing, an external static port on the lower left side of the forward fuselage, and
associated plumbing necessary to connect the instrument to the sources.
The heated pitot system consists of a heating element in the pitot tube, and a
switch labelled PITOT HT on the lower left side of the instrument panel.
When the pitot heat switch is turned ON, the element in the pitot tube is heated
electrically to avoid ice building on the pitot tube in possible icing conditions.
The pitot tube and static vent should not be damaged or obstructed, otherwise
false reading from the relevant flight instruments could degrade the safety of
the flight. They should be carefully checked in the preflight inspection.
The pitot cover is used to prevent water or insects accumulating in the tube
during parking. The pitot tube and static vent should not be tested by blowing in
them, since very sensitive instruments are involved.
G1000 Instrumentation
In the G1000 equipped aircraft, the instrumentation is generated on an LCD
screen, called the Primary Flight Display (PFD), by the Air Data Computer
(ADC), the Attitude Heading Reference System (AHRS), a magnometer, and the
Integrated Avionics Unit (IAU).
The pitot-static system operates in the same way as the conventional aircraft,
the only difference is that the pitot and static signals are fed to the Air Data
Computer which converts the signals into digital format to generate the required
display on the on the PFD screen.
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The pitot-static system also feeds a stand-by conventional altimeter and
airspeed indicator which are mounted on the bottom of the instrument panel, for
use if there is a failure of the G1000 or of the electrical system.
The artificial horizon, and turn and skid indicator receive their attitude
information from the AHRS and the directional indicator receives heading
information from the magnometer.
Additionally there is a vacuum pump (as described above) which powers a
conventional gyro operated artificial horizon, for the stand-by instrumentation.
Stall Warning
The aeroplane is equipped with a pneumatic-type stall warning consisting of an
inlet in the leading edge of the left wing, and an air-operated horn near the
upper left corner of the wind-shield.
As the aeroplane approaches a stall, the low pressure of the upper surface of
the wings moves forward around the leading edge of the wings. This low
pressure creates a differential pressure in the stall warning system which draws
air through the warning horn, resulting in an audible warning at approximately 5
to 10 knots above stall in all flight conditions.
The stall warning can be checked during the preflight inspection by applying
suction over the vent opening. A sound from the warning horn will confirm that
the system is operative.
Alternate Stall Warning System (RG Model Only)
The C172RG is equipped with a vane-type stall warning unit, in the leading edge
of the left wing, which is electrically connected to a dual warning unit located
behind the instrument panel. The vane in the wing senses the change in airflow
over the wing, and operates the dual warning unit, which produces a continuous
tone over the internal speaker at airspeeds between 5 and 10 knots above the
stall in all configurations.
If the aeroplane has a heated stall warning system, the vane and sensor unit in
the wing leading edge is equipped with a heating element. The heated part of
the system is operated by the PITOT HT switch, and is protected by the PITOT
HT circuit breaker.
The stall warning system should be checked during the pre-flight inspection by
momentarily turning on the master switch and actuating the vane in the wing.
The system is operational if a continuous tone is heard on the aeroplane speaker
as the vane is pushed upward.
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Ancillary Systems and Equipment
Lighting
Instrument and control panel lighting is provided by flood lighting, and integral
lighting (internally lit equipment) and, optional post lights (individual lights
above the instruments).
Two rheostat control knobs on the lower left side of the control panel, labeled
PANEL LT and RADIO LT, control intensity of the lighting.
A slide-type switch on the overhead console, labeled PANEL LIGHTS, is used to
select flood lighting in the FLOOD position. Flood lighting consists of a single red
flood light in the forward part of the overhead console. To use the flood lighting,
rotate the PANEL LT rheostat control knob clockwise to the desired intensity.
The external lighting system consists of:
Q
navigational lights on the wing tips and top of the rudder;
Q
single or dual landing/taxi light mounted in the front cowling nose cap;
Q
a flashing beacon located on top of the vertical fin;
Q
strobe lights installed on each wing tip;
Q
a courtesy light recessed into the lower surface of each wing slightly;
outboard of the cabin doors.
All lights (except the courtesy) are controlled by switches on the lower left side
of the instrument panel. The switches are ON in the up position and OFF in the
down position. The courtesy lights are operated by the DOME LIGHTS switch
located on the overhead console. The switch should be pushed to the right to
turn the lights on.
The most probable cause of a light failure is a burned out bulb; however, in the
event any of the lighting systems fail to illuminate when turned on, check the
appropriate circuit breaker. If the circuit breaker has opened (white button
popped out), and there is no obvious indication of a short circuit (smoke or
odor), turn off the light switch of the affected lights, reset the breaker, and turn
the switch on again. If the breaker opens again, do not reset it.
Cabin Heating and Ventilating System
Heated air and outside air are blended in a cabin manifold just aft of the firewall
by adjustment of the heat and air controls.
The temperature and volume of airflow into the cabin is controlled by the pushpull CABIN HT and CABIN AIR control knobs. Both controls permit intermediate
settings.
Cabin heat and ventilating air from the manifold to the cabin is supplied by two
ducts, one extending down each side of the cabin to an outlet at the front door
post at floor level. Wind-shield defrost air is also supplied by dual ducts leading
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from the cabin manifold to outlets on top of the glare shield. Two knobs on each
outlet control sliding valves which permit regulation of defroster airflow.
For cabin ventilation, pull the CABIN AIR knob out.
To raise the air temperature, pull the CABIN HT knob partially or fully out as
required.
For improved partial heating on mild days, pull out the CABIN AIR knob slightly
when the CABIN HEAT knob is out. This action increases the airflow through the
system, increasing efficiency, and blends cool outside air with the exhaust
manifold heated air, thus eliminating the possibility of overheating the system
ducting.
Separate adjustable ventilators supply additional ventilation air to the cabin.
One near each upper corner of the wind shield supplies air for the pilot and
copilot, and two ventilators are available for the rear cabin area to supply air to
the rear seat passengers. Each rear ventilator outlet can be adjusted in any
desired direction by rotating the entire outlet. Rear seat ventilation airflow may
be closed off completely, or partially closed, according to the amount of airflow
desired, by rotating an adjustment knob protruding from the centre of the
outlet.
The cabin heating system uses warm air from around the engine exhaust. Any
leaks in the exhaust system can allow carbon monoxide to enter the cabin.
To minimize the effect of engine fumes, fresh air should always be used in
conjunction with cabin heat.
Carbon monoxide is odorless and poisoning will seriously impair human
performance, and if not remedied, could be fatal. Personal CO detectors are
inexpensive and available at most pilot shops.
Illustration 10d Heating and Air Ventilation Schematic
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Avionics Equipment
The minimum standard fitting is a single VHF radio with hand mike and single
jack point, however most trainers have a dual place intercom with PTT (push to
talk) switch. Many aircraft have upgrades on the avionics systems so an
overview of general operation is included.
Audio Selector
Before operation of any radio
installation the audio selector
panel should be checked. The
audio selector selects the
position of the transmitter and
receiver
for
the
radio
equipment on board.
The common audio selector
panel positions are:
Q
Microphone Selector:
Illustration 10e Audio Selector
Transmit on COM 1, COM
2,... etc. (sometimes called MIC 1, MIC2 for microphone);
Q
Receiver: Listen to COM 1/2, NAV 1/2....etc.; sometimes a BOTH selector
is available (as shown above)
Q
Audio Select: Listen to each channel on speaker, head phone or select
off;
It is considered best practice to use COM 1 for the primary active frequency and
COM 2 for any auxiliary frequencies when required (such as TIBA, ATIS, or
listening ahead to the next frequency), and always reselect the transmit to the
active frequency after use, to avoid selection errors.
Intercom
The intercom sometimes incorporated in the audio select panel contains at least
a volume and squelch control.
The volume control is for adjusting the crew communication volume. The
squelch for adjusting the sensitivity of the crew voice activation. If the squelch is
too sensitive there will be a constant static sound, if it is not sensitive enough it
will be difficult to talk.
Four place intercoms usually will incorporate an isolate switch for isolating the
left seat from the passengers, to prevent interruptions during critical phases of
flight. These may also contain dual volume and squelch controls for the crew
and passengers, and some have ATC playback functions.
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VHF Radio Operations
Once the audio panel has been set, the crew communication established, if
required, and the radio switched on, correct operation should be confirmed prior
to transmitting. All VHF radio installations will have a squelch selection to check
volume and for increased reception when required. This is either in the form of a
pull to test button or a rheostat, turned, until activation is heard. Thereafter
initial contact should be established if on a manned frequency.
Most modern radio installations have an indicator to confirm the transmit button
is active (typically a T or Tx) and often an indication if another station is
transmitting (an R or Rx). This must be monitored when initiating radio
transmissions.
Radio Discipline
Good radio discipline is important to ensure safe and effective radio
communications.
When using VHF radios, unless there is a special reason not to, it is
recommended to use COM1 for the active frequency (the responsible ATC station
or unmanned frequency for the air space you are flying in), and COM 2 for
secondary frequencies (company operations, ATIS, listening on the next
unmanned frequency in advance, air to air non-essential frequencies).
Ensure the volumes of the relative stations are adjusted so that the active ATC
frequency is loudest.
Always return the transmitter (microphone) selector to the active frequency
again to avoid inadvertently transmitting on the wrong station.
In the case of a radio with Rx/Tx indications, always look at the radio your using
before selecting the PTT, to ensure there is no one transmitting, that is, no 'Rx'
indications, and on pressing the PTT, to ensure you have the correct radio,
correct 'Tx' indications.
Transponder
Wherever installed transponders should be switched to standby after start to
allow for warm up time. When entering an active runway for departure, until
leaving the active runway at the end of the flight, the selector should be in ALT if
available or ON.
Even in non-radar airspace, it is vital to have the transponder on, since many
aircraft now contain TCAS (Traffic and Collision Avoidance System), which can
observe other transponder equipped targets for traffic separation purposes.
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The following international transponder codes are useful to remember:
Where no code is specified
Emergencies
Radio failure
Unlawful Interference
2000
7700
7600
7500
Typical IFR Radio Installation (Conventional Aircraft)
The picture on the following page illustrates a typical full IFR avionics
installation. The avionics are often referred to as an “avionics stack”, since they
fit neatly on top of each other in a stack, taking most of the centre console.
G1000 Avionics
On the G1000, the typical “avionics stack” is entirely replaced by selections on
the PFD and MFD, that is, the dual screens of the G1000, and the centre audio
panel.
The Garmin's Integrated Avionics (GIA) computer contains the hardware behind
the avionics display on the PFD/MFD display units (GDU) and the audio panel
(GMA). Along with the transponder the (GTX), these units fulfil the entire
functions of the conventional avionics stack.
The Com 1 and Com 2 controls are available on the top right of the PFD and
MFD display units.
The centre mounted audio control panel provides audio, microphone, and
intercom selections, including a playback function.
Nav 1 and Nav 2 are on the top left of the PFD and MFD display units, The Nav 1
and 2, and the GPS can be selected on the CDI or as bearing indicators,
displayed on the HSI. When the bearing indicators are displayed, the Garmin
provides a GPS distance to the selected VOR or GPS point.
The GPS is integral, controls are via the FMS knob the bottom right of the PFD
and MFD. The display is available on the MFD, or alternatively as an inset on the
PFD.
The ADF and DME, where installed, can be selected to display as bearing
indicators on the HSI.
The Mode S transponder has soft key controls at the bottom of the PFD screen,
and has it's own input to the signal, via the GTX unit to the integrated avionics
unit.
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Where installed, the autopilot selections, with the Garmin GFC700 integral
autopilot are on the centre audio panel. Earlier models have a separate Bendix
King autopilot, which couples to the heading and navigation modes, but not the
altitude bug, this is set on the autopilot itself.
Typical Avionics Installation (Avionics 'Stack')
Illustration 10f IFR Radio Stack
From top: Audio Selector, GPS, Com 1/Nav 1, Com 2/Nav 2, Transponder, ADF,
in this case only the DME is missing.
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Garmin Avionics
Garmin Hierarchy
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FLIGHT OPERATIONS
Note: The C172 has a great deal of variations, and hence many items in this
section will contain items marked “if applicable”. Additionally note, speeds vary
significantly between models and the figures here are for reference only, not for
operational use.
Information in this section must be used as advisory only, and should be
referred to in conjunction with the POH of the aircraft concerned. Owners and
operators must develop their own checks and checklists, with reference to their
POH and the operation being conducted.
PRE-FLIGHT CHECK
The pre-flight inspection should be done in anticlockwise direction as indicated in
the flight manual, beginning with the interior inspection.
Before beginning the pre-flight inspection ensure all covers and external control
locks are removed and stowed in their correct places, and all required
equipment for the flight (maps, headsets, knee-boards, pencils, navigation
tools, fuel strainers and dipsticks, keys etc) is on board, serviceable, and in it's
correct position.
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Cabin
Ensure the required documents (certificate of airworthiness, maintenance
release, radio license, weight and balance, flight folio, flight manual, and any
other flight specific documents) are on board and valid.
Ensure the aircraft flight manual, and supporting documents are available and
accessible in flight.
Check all required emergency equipment for condition, location, and
serviceability.
Perform a visual inspection of the panel from right to left to ensure all
instruments and equipment are in order, including the following items.
Control lock – REMOVE
Ignition switch – OFF
Lights – OFF except beacon
Gear Lever – DOWN (C172RG)
Master switch – ON
Fuel quantity – CHECK
Flap lever – full DOWN (electrical)
Master switch – OFF
Fuel selector valve – CORRECT TANK
G1000 Models
Additionally for G1000 equipped aircraft the following items need to be checked
after selecting the master switch on:
Ensure PFD display visible, check the required annunciators are displayed.
Confirm both avionics fans are operational – turn on each of the avionics buses
separately and confirm the fan can be heard.
With the master switch off, test the standby battery – hold in the TEST position
for approx 20 seconds ensure green light remains on. (This test is described
before start in the POH, however if the standby battery is required for flight it is
preferable to complete the test now).
C172RG
Confirm the gear lever is down before turning the master switch on, to prevent
inadvertent gear retraction.
Operational Check of Lights and Pitot Heat
Before turning the master switch off, if lights and/or pitot heat are required,
switch all lights and pitot heat on. Confirm visually that all required are
operational, and confirm the pitot heat is operational by touch, then turn all off
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again except beacon. This is required for a night flight and a good idea for all
flights. Note: always confirm pitot cover has been removed before turning the
pitot heat on, and take care when touching the hot element.
Exterior Inspection
Visually check the airplane for general condition during the walk-around
inspection, ensuring all surfaces are sound and no signs of structural damage,
worked rivets, missing screws, lock wires or loose connections.
Tail Section
Check aft fuselage and tail section top,
bottom, and side surfaces for any
damage. Air-conditioning and alternate
static if installed unobstructed. Ensure
aft baggage door closed and contents
secure.
Ensure elevator and trim secure and
undamaged,
linkages
free
and
unobstructed,
ensure
balance
weights and fairings secure, check
full and free movement of elevator.
Check rudder linkages and turn-buckles Check beacon, aerials and
secure, unobstructed, and elevator has navigation light undamaged
free movement (do not check full secure.
movement of the rudder with the wheel
on the ground). Check lower tail and tie
down for any sign of tail strike.
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rear
and
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Right Wing
Check flap does not retract if pushed Check all surfaces for any damage,
and flap rollers allow small amount of inspection panels secure, all aerials
play in down position.
undamaged and secure.
Check flap surfaces and tracks for Check aileron for damage, full free
damage, ensure rollers are free and in movement, and security of all hinges,
good condition, and fastenings secure.
control connections, and flutter
weights.
Check condition, security and colour
of navigation light.
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Check top and bottom wing surfaces
for any damage or accumulations.
 Ice or excessive dirt must be
removed before flight.
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Check visually for desired fuel level Check that fuel cap is secure again
using a suitable calibrated dipstick.
after checking the fuel level.
 Note, always confirm the fuel visually – never rely on the gauges alone.
Use sampler cup to check for water, Check the condition and security of
sediment and proper fuel grade.
fairing (if fitted), strut and wheel.
Check the tyre for wear, cuts, bruises, Check the security and condition of
slippage
and
recommended
tyre hydraulic lines, disc brake assembly
pressure. Remember, any drop in and all fastenings.
temperature of air inside a tyre causes
a corresponding drop in air pressure.
 Note, where possible roll the aircraft forward, flat spots often come to rest
on the point of contact with the ground, where they cannot be seen.
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Nose
Check security of nuts and split pins, Check freedom of operating linkage,
state of tyre.
and security and state of shimmy
If applicable, check cowl flaps and squat damper.
switches (RG and FR/R models).
Check condition and security of air filter.
Air filter should be clear of any dust or
other foreign matter. Visually check
exhaust for signs of wear, if engine is
cool check exhaust is secure.
Check landing light and taxi lights for
condition
and
security
(if
nose
mounted).
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Check oil level above minimum for
the required flight.
Before first flight of the day and after
each refuelling, take a fuel sample.
Check strainer drain valve, oil cap
and inspection cover are properly
closed once inspection complete.
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Check propeller and spinner for nicks Security and condition of engine
and security. Ensure propeller blades cowling. On the picture fastening
and spinner cover is secure. When indicated by arrow is not secure.
engine is cold the propeller may be
turned through to assist with pre-start
lubrication.
 Always treat the propeller as live!
Differences on the Left Side
Check static vent unobstructed.
Ensure the pitot tube cover is
removed, and check the pitot tube
for cleanliness, security and ensure
unobstructed.
Check the fuel vent is unobstructed.
Check condition and cleanliness of
landing light (if wing mounted).
Check the fuel tank vent for security
and clear opening passage.
Check Stall Warning Opening for
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stoppage. To check the system, place
a clean handkerchief over the vent
opening and apply suction; a sound
from the warning horn will confirm
system operation.
Final Inspection
Complete a final overall review to ensure all chocks and covers are removed and
the aircraft is in a position to safely taxi without requiring excessive
manoeuvering or power application.
Passenger Brief
After completion of the preflight inspection and preferably before boarding the
aircraft, take some time to explain to the passengers the safety equipment,
safety harnesses and seat belts, operation of the doors/windows and conduct
during flight.
The following items should be included:
Q
Location and use of the Fire Extinguisher;
Q
Location and use of the Axe;
Q
Location of the First Aid Kit;
Q
Location of emergency and normal water;
Q
Location of any other emergency or survival equipment;
Q
Latching, unlatching and fastening of safety harnesses;
Q
When harnesses should be worn, and when they must be worn;
Q
Opening, Closing and Locking of doors and windows;
Q
Actions in the event of a forced landing or ditching;
Q
Cockpit safety procedures (front seat passenger) and passenger conduct
during critical phases of flight.
% It's a good idea to make a briefing card, to use as a prompt for your
passenger brief, to ensure you don't forget anything.
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NORMAL OPERATIONS
Starting and Warm-up
Before engine start or priming, all controls should be set in the appropriate
positions, the instrument panel set up and the pre-start checks completed. The
panel set up should be a flow through in a logical order to ensure all equipment
is set up correctly, serviceable and accessible.
Ensure seats are adjusted carefully for height, forward travel and seat back
position, and locked in place. Ensure all seat belts are secure, and all doors
secure.
Once all the flow items are complete and the panel prepared for starting, a
before start checklist can be completed.
Checklists before start may be broken down into 'master off' and 'master on'
checks, to avoid prolonged time with the master on. These checks may be more
aptly named 'before start', and 'ready to start' checks, or may be combined into
one checklist with a line in between before start, and fully ready to start items.
The latter, master on, items are done only once the aircraft has a start
clearance, and is in a position to immediately start the engine. The reason for
splitting up the checklist is that certain items such as selecting the master on,
should not be done too far in advance of the start, as the delay will run down
the battery.
Q
Once before start flows are completed, the following master off before
start checklist is recommended:
● Preflight Inspection – COMPLETE;
● Tach/Hobbs/Time – RECORDED;
● Passenger Briefing – COMPLETE;
● Brakes – SET/HOLD;
● Doors – CLOSED/LOCKED;
● Seats / Seatbelts – ADJUSTED, LOCKED;
● Fuel Selector Valve – BOTH/CORRECT TANK;
● Carburettor Heat – COLD (if applicable);
● Cowl Flaps – OPEN (if applicable);
● Pitch – FULL FINE (if applicable);
● Undercarraige – FIXED / DOWN (as applicable);
● Avionics – OFF;
● Electrical Equipment – OFF;
● Rotating Beacon – ON.
Q
Once ready to start with all before start items complete, and with the
standby battery armed (if applicable) and master switch ON, complete
the 'ready for start' or 'master on-before for start' checks:
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●
●
●
●
Engine Instruments – CHECKED;
Electrical Instruments – CHECKED;
Annunciators – CHECKED (if applicable);
Circuit Breakers – IN.
After completing all before start checklists, the start is then accomplished as a
procedure, since the actions are required to be carried out in a timely manner,
with prior knowledge of the actions, and cannot be read from a checklist.
Q
When the before start checklist is complete the start procedure:
● Propeller Area – CLEAR.
● Prime – AS REQUIRED (0-3 strokes, or 0-5 seconds, 6 gal/hr);
● Mixture – RICH/AS REQUIRED*;
● Throttle – SET approx ½ centimetre**;
● Starter – ENGAGE;
● Throttle – 1000RPM (maximum);
● Oil Pressure – RISING (within 30 seconds maximum);
● Electrical System – Charging.
*To provide sufficient fuel for starting, the mixture should be full rich at all
altitudes. After successful starting, above 3000ft density altitude, leaning is
required to prevent spark plug fouling during ground handling at low power
settings. Starting for the Lycoming IO360 Lycoming engines (C172R and later)
requires the mixture to be at idle cut-off until the engine fires. If purging is
required before priming, the mixture will also need to be set at cut-off, en-richen
the mixture for priming once the fuel pump runs smoothly or after 5-10
seconds.
**The throttle should be advanced approximately ¼ inch (½ centimetre) to
provide the correct amount of fuel for starting, and to provide approximately
1000rpm after start. If the throttle is advanced too much flooding or backfiring
can occur, which can lead to an induction fire, also the engine will over-rev after
start before the oil has had time to lubricate all parts, causing damage.

Before engaging the propeller, it is vital to check that the propeller area is
clear.
Priming
If the engine is cold, it will need to be primed before starting. Note, if no heat
was felt from the engine area during the preflight, the engine is cold. One to
three strokes of the primer will be required depending on the ambient and
engine temperature. Even in warm outside temperatures a little priming will
improve starting characteristics. Warm engine starts do not normally require
priming.
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Priming before start using the throttle should be avoided as the carburettor is
located at the bottom of the engine and by advancing the throttle, fuel is primed
from carburettor into the engine. As no suction is available from the engine, all
fuel is collected in the carburettor. After igniting the engine, this excess fuel may
explode in the carburettor and/or begin burning in the intake, damaging the
engine.
Fuel injected engines are primed using the auxiliary (electric) fuel pump. With
the mixture rich, the pump is selected on and the throttle is opened to achieve
the desired fuel flow indication, for the desired time, depending on priming
required. In hot conditions, or with a very hot engine, the fuel pump should be
used to clear vapourised fuel before priming by selecting the fuel pump on with
the mixture idle cut-off for a few seconds.
If over priming occurs, engine clearing, turning the engine over with the mixture
at idle cut-off, may be needed. This may be combined with a flooded start
procedure. Ensure starter limits, not more than 30 seconds without cooling, are
observed.
Start
Before engaging the starter ensure the area is clear, ensure you are looking
outside. For starting with the mixture rich, keep one hand on the throttle for
adjustment during starting or as the engine fires, and ensure feet are on the
brakes (light aircraft park brakes are not self adjusting and may have become
weak with brake wear).
The engine is started by turning the ignition key into START position, to turn
over the engine. The key is sprung loaded back to the BOTH and can be released
once the engine starts.
On starting, engine RPM should not be permitted to increase more than
1000rpm until the engine oil pressure has begun rising. If the throttle has been
advanced during starting, or the initial setting is incorrect, it is important to
ensure the throttle is immediately reduced as the engine begins to run. In no
circumstances should the engine RPM be allowed to over-rev on start up. It
takes time for the oil to reach all the moving parts, hence rpm should be kept to
a minimum until sufficient oil pressure has developed and and the engine is
properly lubricated.
After starting, if the oil gauge does not begin to show pressure within 30
seconds, the engine should be shut down, and the fault reported to the
maintenance, before any further starts should be attempted. Running an engine
without oil pressure will cause serious engine damage.
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Any fault in the electrical system or an annunciator fault will also require shut
down. The start process is only complete once the pilot is assured that the
aircraft engine is fully serviceable for flight. Only then the after start checks can
begin.
Flooded Start
If the engine has been over primed, a flooded start may be completed. This
involves starting the engine with the mixture idle cut off and the throttle fully
open. As the residual fuel in the cylinders ignites, the mixture is increased to full
rich and simultaneously the throttle is reduced to idle. The procedure can also
be completed with the throttle set at a reduced power setting,
this is less
effective in clearing the excess fuel but makes the starting procedure slightly
easier.
This procedure does require some practice to avoid damaging the engine by
application of excessive rpm just after start, and must be completed under
supervision the first time it is attempted.
If the engine has been over primed, a clearing cycle may be needed. This would
naturally occur in the starting process when using a key starter, as if the engine
does not start within 30 seconds, cooling must be allowed before continued
attempt to start. Before ignition occurs the clearing procedure and starting
procedure are identical. Where a separate magneto and start switch is fitted, a
dedicated engine clearing procedure would be completed with the magnetos off
and the throttle must be fully open.
C172R and C172S Start Procedure
The recommended procedure for the late model Cessna 172R and later produced
from 1996 on, is to use a flooded start procedure, with the throttle set for idle,
that is approximately ¼ inch in. After priming using the fuel pump, the throttle
is reset to idle and the mixture is reset to idle cut off, the starter is engaged and
the mixture is richened as the engine ignites.
The engine should not normally be primed when hot, unless starting is difficult,
as it floods easily.
After Start
After start checks ensure all the critical items are completed prior to taxi. The
time spent completing the after start checks properly will also assist with the
engine warm-up prior to taxi.
At airfields above 3000ft density altitude, the mixture should be leaned for taxi
to prevent spark plug fouling. The recommended procedure is to lean to peak
rpm at 1200rpm.
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A “live mag.” check should be done at this point, by selection of the left and
right positions to confirm both are operating. This is not an integrity check as
the engine is still cold. The purpose of the check is to prevent unnecessary
taxiing to the run-up point should one magneto have failed completely.
Where available, copy down the ATIS. Complete a self briefing on the expected
taxi routing. Check and set any available radios and navigation aids as required.
The direction indicator must be set to the compass for orientation purposes.
The transponder is set to standby for warm up, so that it is ready for use on
departure, and the assigned squawk code set.
If the flaps were left down during the pre-flight inspection, they must be
retracted, or set for takeoff, both to aid visibility, and because taxiing with the
flaps fully down incorrectly signals a hijacking is taking place.
Once after start procedures are completed, an after start checklist where
available should be completed:
Q
The following after start checklist is recommended:
● Mixture – SET;
● Flight Instruments – CHECKED AND SET;
● Engine Instruments – CHECKED;
● Flaps – RETRACTED/SET;
● Transponder – STANDBY/GROUND.
Taxi
Before taxi, confirm the taxi route to ensure you know which taxi ways to take,
and select the taxi light on to indicate you're about to move.
The brakes must be tested as soon as possible after the aircraft begins moving.
Most of the engine warm-up is conducted during taxi. If the engine is cold, for
example on first flight of the day, or when it is anticipated that high power
settings may be needed during taxi, additional time may be needed to allow the
engine to warm up prior to taxi. Ideally this warm up period should be sufficient
to allow the CHT, if fitted, to increase into the green range.
If the flight is being taken from an airfield where no taxi is possible (or only very
short taxi) additional warm-up time should be allowed before the engine run-up
and take-off .
The cowl flaps (where fitted) should not be closed for this warm up as this will
provide uneven temperature distribution which may damage the engine.
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Taxi speed must be limited to a brisk walk, the aircraft is is its most unstable
condition on the ground, especially with strong winds that may reach minimum
flying speeds. When maneouvring around other aircraft, buildings, or
intersections, an even slower speed and extra care must be taken.
Brake use should be kept to a minimum by anticipation of slowing down or
stopping followed by reduction of power to idle prior to applying brakes. Except
for asymmetric braking during tight turns, never apply power and brakes at the
same time. This is unnecessary, producing counter active forces, and causes
additional wear on the brakes.
Flight control surfaces should be held in the correct position to ensure the
aircraft is not rocked or displaced and controls are not subjected to unnecessary
forces by the prevailing wind. The diagram below illustrates positions of controls
in relation to the relative wind for the best aerodynamic effects during taxi.
The following phrase may be helpful as a memory aid:
CLIMB INTO WIND,
DIVE AWAY FROM THE WIND.
That is, taxing into wind, pull back (climb) and turn towards the wind, taxing
with the wind behind you, push forward (dive) and turn away from the wind.
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Additionally, controls should be held firmly to prevent buffeting by the wind, and
whenever taxiing over rough surfaces, bumps, or gravel, elevators should be
held fully aft to reduce loads on the nose wheel and propeller damage.
During the taxi, the flight instruments subject to movement, and navigation
instruments should be checked. For a VFR flight one directional turn is sufficient.
For IFR instruments functionality should be checked in both directions, and full
navigation aid functionality (where navigation aids are available) must be
confirmed prior to use.
Q
During a turn on the ground the following observations should be seen:
● Compass and Direction Indicator –
INCREASING/DECREASING;
● Attitude Indicators – STABLE (not moving);
● Slip/Skid Indicator – SKIDDING;
● Navigation Instruments – TRACKING.
Q
Once the above items are actioned, then complete a taxi checklist:
● Brakes – CHECKED;
● Flight Instruments – TESTED AND SET;
● Nav Instruments – TESTED AND SET.
Run-up Before Takeoff
The run-up and before takeoff checks are usually performed on the holding
point. Advance the engine to 1700rpm (or 1800rpm depending on model) and
perform the following checks prior to take-off:
Q
Prior to take-off from fields above 3000ft density altitude, the mixture
should be leaned. As the air pressure decreases with altitude the air
density also decreases and so the engine receives less mass of air. If the
mixture is left in the full rich position, the air/fuel ratio will not be correct
(too much fuel or the mixture too rich). The correct air/fuel ratio is
required for engine to produce maximum available power.
● The following procedure may be used for leaning the mixture
prior to takeoff: lean the mixture by rotating the mixture knob
anticlockwise till peak rpm, then enrich the mixture for about 3
rotations. This procedure is similar to that carried out en-route
for leaning. This check may also be performed at lower
altitudes to check correct operation and setting of the mixture,
however the mixture should be returned to full rich before
takeoff;
Q
Carburettor heat should be checked by pulling and pushing the
carburettor heat control knob for a brief period of time. The engine rpm
should drop about 100rpm during the carburettor heat operation. Don’t
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operate the system for prolonged period of time, because when the knob
is pulled out to heat position, air entering the engine is not filtered;
Magnetos check should be done as follows:
● Move ignition switch first to L and note the rpm drop.
● Next move the switch back to BOTH to clear the other set of
plugs and regain the reference rpm.
● Then move the switch to R position, note the rpm drop and
return the switch to BOTH position.
● Rpm drop in either L or R position should not exceed 150rpm
and show no greater than 50rpm differential between
magnetos;
If the aircraft has a constant speed prop, a pitch check should be carried
out. Select the pitch control to full course, noting a drop in rpm, rise in
manifold pressure, and drop in oil pressure, select full fine again, allowing
no more than around 300rpm drop to prevent unnecessary stress on the
engine, and note all parameters return to normal. Repeat twice more for
a cold engine, ensuring the mechanism is adequately lubricated with
warm engine oil and operating smoothly, for a warm engine once is
sufficient if the correct operation of the CSU can be established.
Verify proper operation of alternator, alternator control, suction system;
and correct indications (in the green) of all engine control gauges
DI may be set to compass at this point as engine interference and
suction operation is more indicative at 1700rpm
Reduce the engine rpm to idle to confirm idle operation on warm engine
at correct mixture settings, return to 1000 rpm for Pre takeoff checks
Q
Q
Q
Q
Q
Pre-Takeoff Vital Actions
The flight manual provides the “minimum required actions” before takeoff,
generally there are some additional operational items to check. Many flight
schools or operators will have their own check lists and/or acronyms for the pre
take-off checks. Acronyms are highly recommended for single pilot operations,
and ideally should be used to complete memory checks followed by an approved
checklist.
One of the most popular acronyms for pre takeoff checks is detailed below:
Q
Q
Too
Many
Q
Q
Pilots
Go
Q
Fly
Trims and flight controls – tested and set;
Mixture set for takeoff;
Magnetos on both;
Pitch full fine (as applicable);
Gills (Cowls) open;
Gyros uncaged (as applicable) and set;
Fuel contents checked, selector on correct tank,
primer locked, fuel pump as required (normally off);
Flaps set for takeoff;
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Q
In
Q
Q
Heaven
Early
Instrument panel check from right to left, DI aligned
with compass, altimeter set, clock check, navigation
instruments set for departure, autopilot off;
Hatches and harnesses secure;
Electrics checked, circuit breakers checked, systems
checked.
The before takeoff checks and actions should be followed up by a pre-takeoff
checklist.
Q
After completing pre takeoff flows, the following pre-takeoff checklist is
recommended:
● Run-up – COMPLETE;
● Trim – TESTED and SET for takeoff;
● Flight Controls – CHECKED, AUTOPILOT OFF;
● Flight Instruments – CHECKED and SET
● Flaps – SET for takeoff;
● Fuel – CHECKED : on BOTH, quantity checked, primer
locked, pump off, as applicable;
● Mixture/Pitch/Power – CHECKED*/SET;
● Departure Brief – COMPLETE**.
*Confirm the applicable required takeoff power, for normally aspirated fixed pitch, this is the
minimum and maximum static rpm, approximately 2300-2400rpm (varies with model). For
normally aspirated CSU this will be the redline rpm, and within approximately 1 inch of ambient
pressure.
**The departure briefing should include the normal takeoff, emergencies on takeoff, and any
applicable departure routing or clearance.
With all checks complete, and once fully ready for takeoff, continue to the
holding point for line-up.
Takeoff
Just like a great approach is an essential part of a great landing, a good line up
procedure is a very important part of a safe take-off.
Once cleared to line up, a logical sequence of checks is best:
Crossing the holding point onto the runway, wherever it occurs (e.g. either
entering to backtrack, or to line up, or just to taxi to the holding point where no
parallel taxiway exists), should trigger two items: the strobe lights and the
transponder. Note – if the runway is exited again e.g. when backtracking to a
holding point, when exiting the runway both will go off again, triggered by
crossing the holding point clear of the runway.
Once approaching the point of line up, a check of the essential items for takeoff,
flight instruments, engine instruments, and windsock is important. At this point
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it's also a good idea to complete a final cockpit scan to ensure fuel, flaps, and
mixture are set, and take a mental note of the time.
The last item, once fully lined up, is to confirm the runway heading is correct.
This is of vital importance both to check the runway is the correct one, and to
get an accurate check of the magnetic heading, and is the only item that needs
to be done after completing the line up.
The landing light is turned on when takeoff clearance is received or, when
unmanned, with the final radio call for takeoff, which ensures you have a
clearance, or have made the essential radio call. At this point ensure the runway
is clear.
Unless on gravel surfaces, or with traffic on final approach, it is always good
airmanship to line up straight on the runway centreline, stop. Ensure the line up
checks are complete, and ensure the aircraft is aligned with the runway
centreline, then runway is clear, and correct.
The following items should be selected and checked on line up, (these also have
a helpful acronym):
Q
Q
Q
Q
Q
REmember Runway - CLEAR from obstruction, correct;
Engine temperatures and pressures CHECKED/GREEN;
What
Windsock – CHECKED, direction and strength (confirm
against reported wind), position control column
accordingly;
To
Transponder – ALT (TA/RA or ON as applicable);
Do
DI – ALIGNED with compass and indicating runway
direction;
Last
Landing lights and strobes – ON;
Takeoff is always carried out under full power with the heels on the floor to avoid
accidentally using the toe brakes.
It is important to check full-throttle engine operation early in the takeoff run.
Any sign of rough engine operation or sluggish engine acceleration or less than
expected takeoff power is cause to immediately discontinue the takeoff.
For fixed pitch propellers, the engine should run smoothly and with constant
static rpm, minimum 2300 to maximum 2400 rpm* (or as applicable in the POH,
depending on engine installation). For CSU models, maximum rpm should be
developed (2700 or 2800) and manifold pressure should be within a maximum
1” of ambient pressure**.
*Engines without a CSU will not develop full power without assistance from the relative airflow,
and will have a minimum and maximum “static” rpm, that is the minimum and maximum rpm
which should be obtained stationary, which must be checked early in the takeoff run.
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**CSU aircraft should develop full rpm, and close to ambient pressure, this should be checked
on the manifold pressure gauge prior to start, to avoid gauge errors.
When taking off from gravel runways, the throttle should be advanced slowly.
This allows the aeroplane to start rolling before high rpm is developed, as loose
gravel is harmful to the propeller. On a rolling takeoff the gravel will be blown
back from the propeller rather than pulled into it.
Normal Takeoff
In a normal takeoff, the elevator should be slightly aft. This protects the nosewheel by “holding the weight off” the nose-wheel with aerodynamic pressure.
This will also reduce frictional drag, assist with a smoother takeoff roll, and a
smoother rotation at the right speed.
Keep the aircraft straight on the runway, and balanced during the climb with
rudder (this will require right rudder due to the slipstream and torque effects).
Rotate at the applicable normal takeoff rotation speed, approximately 50-55kts,
depending on model.
Once airborne initially maintain the applicable best rate of climb, at a safe
altitude, not below 300ft AGL, confirm the speed is above 60kts and retract the
flaps if used, then complete the after takeoff checks.
Wing Flaps Setting on Takeoff
Using the flaps for takeoff will always shorten the ground roll, but it will also
always reduce climb performance of aircraft. Which one has more effect on the
total takeoff distance, that is the distance to a height of 50ft above the runway,
is determined by the manufacturer in flight testing and prescribed in the POH as
the recommended short field takeoff technique.
Most C172 models specify flap up for short field takeoff. Models with larger
engines (C172P, 1981 and later, 160 and 180hp), specify flap 10 for short field
takeoff. Early models specify flap 10 for minimum ground run take-off, and flap
up for obstacle clearance take-off, which provides the best insight into the
effects of flap on takeoff for the C172.
Note, takeoff data is usually only provided for the recommended short field
takeoff, however climb data is provided for a clean climb, leaving a paradox. The
following advice should be viewed with full consideration for field length.
Selection of 10 degrees flap provides higher lift, reducing frictional drag, and
permits takeoff speeds approximately 5kts lower than with flaps up. This results
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in reducing the takeoff roll by approximately 10%. However this advantage is
lost if flaps up speeds are used, or in high altitude takeoffs at maximum weight
where climb performance is marginal.
The 10 degree flap takeoff is sometimes referred to as the “minimum ground
run” takeoff. And, field length permitting, it is recommended by Cessna for all
soft field takeoffs. Seaplane models normally always require flap for takeoff, so
the increased lift counteracts the effects of the high frictional drag from the
water, (see more on soft fields below).
Use of 10 degrees wing flaps is not recommended for takeoff when there are
obstacles in the climb out path, or at high altitude in hot weather (high density
altitudes). If an obstruction requires the use of a steep climb angle, after lift off
establish climb out at the recommended obstacle clearance speed specified for
the flap setting used. This speed provides the best overall climb speed to clear
obstacles. Because of the low margin above the stall speed, care should be
taken in gusty conditions and in consideration of the turbulence often found near
ground level.

If flaps are used for takeoff, they should not be retracted below 300ft AGL,
and only once clear of any obstacles, and after a safe flap retraction speed of
60kts is reached. Flaps retraction causes a loss of lift, prior to gaining any
benefit from the reduced drag. Retracting the flaps with insufficient speed may
result in loss of altitude or a stall. While accelerating to the minimum safe
speed to retract the flaps there will be temporarily a minimum climb
performance.
Once the obstacles have been cleared, and a minimum safe altitude reached
(300ft AGL), the aircraft can be accelerated and flaps retracted (upon passing
60kts), where the normal flap-up initial climb-out speed (Vy) can be established.
Short Field Takeoff
For a short field takeoff, to achieve the required performance, as mentioned in
the previous paragraphs, the applicable technique and flap setting established
by the manufacturer, and specified in Section 5 of the POH, must be used.
The Cessna 172 POH does not specify a short field takeoff rotation speed. It
requires a 'tail low' or 'aft elevator' technique for short field takeoff. The ground
roll is started with slightly aft elevator taking the frictional drag off the nose
wheel while not significantly increasing the aerodynamic drag. No rotation speed
is provided, the requirement is for the aircraft to 'lift off at minimum speed', at
the earliest possible point, and once airborne accelerate to Vx in ground effect.
This technique requires a lot of pilot skill, and some operators prefer to specify a
rotation speed, usually around 50kts, or 5-10kts below the normal rotation
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speed. However, only when the POH specified technique is used will the
minimum distance be achieved.
Where there are no obstacles, once airborne, the aircraft may be accelerated to
Vy. When there are obstacles, the recommended short field speed, Vx with the
applicable flap setting, should be maintained until clearing obstacles.

Where climbing at Vx with flap 10, the aircraft must be accelerated to above
the minimum retraction speed, usually 60kts, prior to raising the flap. Once
clean, the climb may be continued at Vx clean, or usually, since obstacles are no
longer a factor, at Vy. Acceleration to above minimum flap retraction speed is
usually accomplished quickly, however it should be noted, that climb
performance is marginal during the acceleration phase.

Where flying an an RG model, the POH specifies to retract gear above 63kts,
and AFTER obstacle clearance, (that is, not just on first indication of a positive
rate of climb, nor at the end of the usable runway like most retractable
procedures). The Cessna single engine system of gear retraction has the
distinctive feature of initially causing more drag as the gear moves into the
slipstream, before retraction, and therefore should not be retracted too early.
The figures and methods prescribed in the flight manual are those flight tested
and certified by test pilots for the required performance. Any deviation from the
recommended procedure should be expected to give a decrease in performance.
Soft Field Takeoff
For soft or rough field takeoffs it is recommended to use the highest flap setting
permitted for the field length, this may be 0, 10, or 20 depending on model and
additional fittings, e.g. a STOL kit. The extra lift provided helps reduce the high
frictional drag of the soft field, reducing the ground roll.
Soft or rough field takeoff's are best performed by lifting the aeroplane off the
ground as soon as practical in a slightly tail-low attitude, then once airborne
accelerating to the required speed (Vy or Vx, as described above in Short Field
Takeoff). It is more essential to reduce the ground friction as soon as possible,
as on a soft field the frictional drag has a much higher effect on hindering
acceleration during the ground roll.
The Cessna POH typically does not provide very much information on the effect
of surface conditions on takeoff rolls. A factor is provided for dry grass fields
only. It must be remembered that frictional drag caused by rough or soft
surfaces including the effects of recent rain, long grass, or sand, are extremely
detrimental to your performance. A table of recommended figures from the
UKCAA is provided in the PERFORMANCE section of this book, and may be used
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as a guideline in these situations. When in doubt always add a significant safety
factor.
Crosswind Takeoff
Crosswind takeoff is commenced with controls into wind, then as speed
increases controls are gradually straightened. It is vital that the into wind wing
is not permitted to lift. To achieve this, takeoff is achieved with a very slight
amount of aileron into wind, at the point of rotation. The amount of aileron is
only enough to prevent the into wind wing lifting first, and will assist with the
after takeoff heading change (crab), but not enough to produce any significant
bank.
During a crosswind takeoff, if the aircraft becomes airborne too early, it will tend
to move sideways with the air mass and sink back onto ground with strong
sideways movement which may damage the undercarriage.
The recommended technique, where field length permits, is to hold the
aeroplane firmly on the ground to slightly higher lift-off speed, then positively
lift-off with a backward movement of the control column.
Crosswind takeoff should be completed with the minimum required flap setting
for the field length, allowing for a higher rotation speed. This helps prevent
lifting off prematurely, and makes the aircraft more controllable on the ground
and in the final stages of the takeoff, from airborne to 50ft.
Once airborne, while maintaining balance, the aircraft nose is turned slightly into
wind to prevent drift on climb-out, termed, ‘crabbing into wind’.
Maximum Demonstrated Crosswind Component
The maximum demonstrated crosswind component is measured at a height of
33 feet. This is the highest value for which the aeroplane has been tested during
takeoff and landings.
The POH definitions describes the “Demonstrated Crosswind Velocity” as follows:
“Demonstrated Crosswind Velocity is the the velocity of the crosswind
component for which adequate control of the aeroplane during takeoff and
landing was actually demonstrated during certification tests. The value shown is
not considered to be limiting.”
Although it is not considered limiting, it is good practice to not exceed this
value. It is also vital that an inexperienced pilot should reduce this value even
further.
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Some early models may not included a maximum demonstrated crosswind in the
operating handbook, in later models a maximum demonstrated crosswind
component of 15kts or 20kts is specified, depending on model.
Takeoff Profile
Normal takeoff should consist of the actions depicted below in each phase of
departure.
To allow for all variations of C172, pitch and gear have been included in the
takeoff profile considerations. This also provides a profile which is consistent for
all conventional light aircraft operations, and in fact, aside from the different
power controls, it remains consistent with all larger aircraft too.
Flap, power and speed need to be concisely managed, and there is a specific
requirement and order for each at each phase in the takeoff, and this does not
change.
The takeoff profile can be summarised as follows:
1. Minimum speed/recommended rotate speed (approximately 50kts for a
normal takeoff): Rotate- raise the nose wheel/lift off, tap the brakes to stop the
wheels moving, reducing the vibrations often felt from imbalances when they
are allowed to decelerate on their own.
2. At the end of the runway, at the latest, a minimum speed of 60kts should
have been achieved.
For the C172RG, once no usable runway left, and a positive climb achieved, and
above any minimum gear retraction speed, tap brakes (again for a cross check
to prevent damaging the wheel bay) and raise the gear.
3. Once airborne: Accelerate to initial climb speed (60-75kts), best angle of
climb (approximately 60kts) when obstacles exist or best rate of climb
(approximately 75kts) to achieve maximum height in minimum time and reduce
the risk exposure close to the ground.
4. At a safe height away from the ground and above obstacles in the takeoff
path: (allowing for further acceleration if required, typically not below 300ft
AGL), accelerate to above the minimum flap retraction (60kts) and raise the
flaps.
5. Once flaps are retracted, if applicable reduce to climb power (maximum
continuous), this is typically only required on CSU models. Power reduction is
commenced only after you have removed all the drag, and above an altitude
permitting a reasonable chance of a safe outcome from an engine failure, whilst
observing the take-off power limitation time (typically 5 minutes if applicable).
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With a CSU, this should be done by first reducing the manifold pressure, then
RPM, followed by mixture setting if applicable. Reducing RPM will increase the
manifold pressure slightly. Fine-tuning of the manifold pressure may be done
after adjusting the mixture, once all the engine parameters are stable.
6. Continue to climb at best rate of climb until above 1000ft AGL minimum for
VMC/VFR operations; 1500ft or above MSA, whichever is higher in IMC or in
mountainous terrain.
7. If performance permits, accelerate to an en-route climb, to achieve the
desired climb profile (80-90kts or approximately 500 ft/min).
8. Complete the after takeoff checks (flows) and/or after takeoff checklist as
available.
A takeoff profile summary diagram can be seen below.
Takeoff Profile Diagram
1. Keep
elevator
slightly tail
low, check
fuel flow for
placard, lift
nose wheel
approx
50kts.
2.DER:
60kts
minimum.
No runway
left raise
gear (RG).
3.Climb at
best angle
(Vx) or best
rate (Vy) of
climb as
required.
4.Clear of
obstacles/
safe height:
Accelerate to
Vy, above
60kts
minimum
raise flaps.
5. Within 5
minutes, and
above
500ft AGL,
reduce
power to
Maximum
Continuous
(if applic.).
6. Climb at
best rate of
climb to
minimum
1000ft AGL
(1500 IMC).
7.Accelerate
to cruise
climb or as
required.
8. Complete
ATO checks.
After Takeoff Checks
After takeoff, the brakes are applied gently, and above minimum speed gear is
retracted for retractable models, then select the landing light off. The purpose of
applying is brakes is to gently stop the wheels turning, to prevent vibration as
the wheels slow down and to prevent damage to the wheel well for retractable
models. The landing light is selected off at this point, as the takeoff is complete,
and many aircraft have landing lights on the undercarriage, so it's a good habit.
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Once above minimum flap retraction altitude, and above minimum flap
retraction speed, raise the flap. After flap retraction, where required, reduce
power to maximum continuous (C172RG, FR/R172K), for constant speed models
this is achieved by reducing manifold pressure, then pitch, and then leaning
mixture (if required, for takeoff above 3000ft density altitude).
Once established in the climb with all the actions complete, the after takeoff
checklist is completed.
Q
Typical after takeoff checklist is as follows (BUMFFEL):
● Brakes – CHECKED -on and off;
● Undercarriage – FIXED/UP (as applicable);
● Mixture / Pitch / Power – SET for climb;*
● Flaps – UP;
● Fuel – CHECKED (on BOTH, quantity checked, primer locked, pump
off, as applicable);
● Engine’s Temperature & Pressure – CHECKED;
● Landing Light – OFF / AS REQUIRED.
Note, the sequence of brakes, gear, landing light, raising flap, then reducing
power, power, pitch, mixture, as described above, is very important; the
checklist sequence differs, however, as the checklist is completed after the
items are complete, and is sequenced both for consistency in after takeoff and
downwind/approach checks, and for convenience of the acronym.
Climb
The normal flap up climb is made at an airspeed of 70-80kts using full, or, if
applicable, maximum continuous power.
For a maximum rate climb, the best rate of climb speed- Vy, approximately
70kts, is used. This enables reaching the desired altitude as quickly as possible,
as it gains the greatest altitude in a given time.
The best rate of climb reduces with altitude, from around 74kts at sea level, to
around 68kts at 10,000 feet (varying slightly with model).
When required to clear an obstacle, the maximum angle climb speed – Vx,
approximately 60kts, is used. This gains the greatest altitude for a given
horizontal distance. Vx has the minimum permissible margin above the stall,
and the slow airspeed results in reduced cooling causing higher engine
temperatures. For this reason, Vx should only be used when needed, for
example for short periods while clearing obstacles.
If sufficient performance allows, a cruise climb may be achieved by lowering the
nose to maintain a rate of climb of approximately 500ft/min, with a climb speed
of 80-85kts (90-100mph). This may be only possible at lower altitudes, as if the
rate of climb is maintained then the speed will begin to reduce towards Vy. For
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this reason it is always best to trim maintain an airspeed, and elect to reduce
the speed once the rate of climb drops below an acceptable level.
With a heavy aircraft or high altitudes and temperatures, the aircraft will have
insufficient climb performance to accelerate to a cruise climb, and extended
climb at Vy may be required. For extended climbs at Vy, engine temperatures
must be monitored carefully, and an intermediate level off may be needed for
cooling purposes. These intermediate level off's can also be used for lookout, as
visibility during the climb is obscured.
Leaning during extended climbs may be required to maintain efficient engine
performance, and/or to reduce fuel consumption. Leaning is generally only
required when the altitude change is more than 3000ft, for example when
climbing from the coastal areas towards mountainous terrain or when high
cruise altitudes are required for range.
Leaning during the climb should be made in a similar way to the procedure for
richening during descent, that is, around one turn per 1000ft leaner whilst
monitoring engine temperatures, EGT and (if applicable) fuel flow gauge. The
takeoff and climb mixture settings should always be slightly richer than cruise
for engine cooling, and this method ensures that the climb mixture is never
significantly lower than that set and checked for the takeoff.
Cruise
Normal cruising is performed with the power in the recommended cruise range
(green arc). This is typically between 2200 - 2400rpm at will achieve a true
airspeed or around 105kts on most models (a little higher on late models, and
those with larger engines). The manoeuvres power range is normally from 1900
to 2700rpm (these power settings will vary with model).
The mixture should be leaned during the cruise for the most efficient engine
operation, to prevent carbon fouling, and to achieve the best fuel consumption.
Carburettor ice can be experienced during low rpm operation and can be
evidenced by a sudden rpm drop. Carburettor ice can be removed by application
of the Carburettor heat system by pulling the Carb heat knob. Since the heated
air causes a richer air/fuel mixture, the mixture setting should be readjusted
when the carburettor heat is used in cruise flight. The use of the carburettor
heat is also recommended during flight in very heavy rain to avoid the possibility
of engine stoppage due to excessive water ingestion.
Cruise Checks
During the cruise it is important to have periodic aircraft status checks. These
checks will not form part of a checklist, as they are considered normal flying
duties and should be done regularly as part of good airmanship, however it is
helpful to have an acronym to remind us what to check.
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Q
One of the recommended cruise checks is defined by the acronym
'HATFIRE', as follows:
● H – Heading – CHECKED, heading aligned/synced, track/wind
noted, heading bug set;
● A – Altitude – CHECKED, descent profile checked, MSA
checked, QNH set, altitude bug set;
● T – Time, CHECKED, noted, ETAs revised, ATAs updated,
to/from way-point, timer set;
● F – Fuel – CHECKED, correct tank (selector on both) remaining
flight, time/time to diversion considered;
● I – Instruments – SET AND CHECKED, suction, amps,
annunciators; Icing – CONSIDERED, carb. ice/engine ice as
required
● R – Radios – SET AND CHECKED, required main and standby
● frequencies set, navigation frequencies set;
● E – Engine – CHECKED, temperatures and pressures green,
electrics checked, mixture set, crab. heat, and cowl flaps
closed/as required/applicable.
HATFIRE is also a useful way-point checklist, at top of climb, or at turning points
or en-route way-points, to be completed after the way-point to ensure all
required items were completed. Generally as many items as possible related to
each check should be considered. This ensures redundancy, and so helps to
avoid omissions.
Mixture Setting
Note: The information herein is based on the factory Cessna 172 engine installations, for any
modifications, refer to the instructions in the applicable POH supplements.
Mixture setting is carried out to achieve smooth engine operation and either best
development of power, or minimum fuel consumption. As an overriding factor,
mixture must be set to keep engine temperatures within acceptable limits.
Because of cylinder variations in conventional horizontally opposed piston
engines, the mixture setting should normally be set slightly rich of the “peak
EGT” setting, to allow for smooth engine operation, improved cooling, and
prevent detonation.
This is achieved by rotating the knob counterclockwise until maximum rpm is
obtained with fixed throttle setting, where upon the rpm begins to decrease on
further leaning accompanied by slight rough running as cylinders begin to
misfire. Then the control is rotated clockwise until rpm starts to decrease again,
normally one turn to reach peak rpm again then one or two turns thereafter to
achieve the desired margin.
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The Exhaust gas temperature (EGT) indicator may be used as an aid for leaning
the mixture when cruising at 75% power or less. To adjust the mixture using
EGT, lean the mixture to establish the maximum or 'peak' EGT, by noting when
the EGT ceases rising and begins to drop, enrich the mixture to the peak, and
thereafter continue to the desired increment rich of peak. Providing cylinder
temperatures are acceptable, mixture may be set at peak EGT for best economy.
Best power (peak rpm as described above) is approximately 100 degrees rich of
this peak, although the rpm is usually a better reference for best power on fixed
pitch aircraft.
There is normally a small reference needle on the EGT gauge, which should be
manually set to the peak once established, for monitoring of changes. If set for
best power, the temperature should now indicate approximately 100 degrees
cooler than the reference needle, allowing any changes in the mixture setting to
be easily detected. Changes in outside temperature with location will alter the
air density, and this will affect the mixture and EGT, and may require small
adjustments or resetting from time to time. For this reason the EGT gauge must
be included in the periodic cruise checks of engine temperature and pressure.
Any change in altitude or throttle position during the cruise will require a
readjusting of the mixture setting.
In high ambient temperatures, a slightly
rich mixture can be used to aid cooling.
Setting the mixture one or two turns richer,
or another 50-100 degrees cooler than rich
of peak rpm can lower CHT temperatures
by up to 30 degrees.
Later models specify leaning to peak rpm
Illustration 11a CHT and EGT vs OAT
for taxi at 1200rpm to allow for power
variations. If leaning at 1000rpm, the
setting should be a few turns rich of peak rpm or there may be power loss
during taxi.
For operations above 3000ft, leaning is required for take-off and climb.
For take-off, leaning is normally carried out during the engine run-up. This is
done the same way as leaning in flight, but using peak rpm as the primary
means of determining best mixture (since at low power settings the EGT will
usually be too low for reliable readings).
Where maximum power is not required, with the throttle set at run-up rpm
(1700 or 1800 rpm, depending on model), lean the mixture to peak rpm, and
then enrichen approximately half the distance to peak. The rich mixture
provides additional cooling at high power.
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If maximum power is required for a maximum performance take-off where field
length or climb out performance is critical, the mixture must be set to peak rpm
at full static power. When operating at full power, with the mixture leaned for
peak rpm, the temperatures must be monitored carefully.
 It is recommended, for prolonged engine life, to maintain the CHT below 400
degrees wherever possible, and operations above 400 degrees should be
transient only, never sustained. Operating at full power and peak rpm in high
ambient temperatures is not recommended.
For fuel injection, where a fuel flow placard for maximum power exists (R172
models), it must be used for the take-off power mixture setting, an example of
a fuel flow placard from a R172K is displayed below.
FUEL FLOW AT FULL THROTTLE, 2600 rpm
SL
16GPH
4000ft
14GPH
8000ft
12GPH
12,000ft
10GPH
The mixture setting obtained on the ground can normally be maintained to top
of climb, although further leaning may be needed in extended climbs of more
than 3000ft altitude change. The rule of thumb of one turn per 1000ft, as used
in a descent, may be applied for leaning in the climb. If an EGT reference line is
available, and has been set accurately in the cruise in similar ambient
conditions, this may be used for comparison. Peak climb EGT will always be
slightly higher than cruise EGT (the reference line) because of the higher power
setting, and mixtures should err towards the rich side for improved cooling
during the climb. Therefore, comparison of EGT in the climb to EGT in the cruise
can provide a convenient crosscheck, if the EGT drops significantly below the
cruise peak reference setting, then the mixture is becoming too rich, if above
the line it is becoming too lean.
When increasing to full power above 3000ft density altitude, the same rule for
takeoff may be applied, that is, to enrichen half the travel from the cruise
setting, monitoring resulting the CHT and enrichen if required.
If an aircraft is equipped with individual cylinder EGT and CHT monitoring, the
manufacturer of these engine gauges may have a procedure for mixture setting
and monitoring. Many installations of this type permit operation leaner than that
specified by Cessna, however this must be done with considerable caution and
careful monitoring, as a change in ambient conditions may put the mixture too
far lean of peak, risking detonation or loss of power. The applicable procedure
will be detailed in the associated POH supplement and should be reviewed
carefully prior to flight.
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During descent the mixture should be enrichened approximately one turn per
1000ft or one turn per 3-5nm to arrive at the recommended landing mixture
setting before or on joining the traffic pattern. Again the EGT reference line may
be used as a comparison for a descent mixture setting cross-check. By the time
the aircraft rejoins the circuit pattern, the mixture should be at the take-off
required setting, to ensure power is available in the case of a go-around.
During taxi or continued low power operations at high density altitudes, the
mixture must be leaned to prevent spark plug fouling, which is most common,
and most potentially harmful effect of a rich mixture at low power.
Descent, Approach and Landing
Approaching the airfield for landing, descent and approach checks should be
completed.
Descent checks are completed early during the descent, or just prior to the start
of the descent, depending on how long the descent is. Descent checks may
sometimes be termed 'joining' checks, since they are only completed when you
have vacated the circuit and are re-joining for landing, however this may be
confused with approach checks (which are completed just prior to joining the
circuit where no downwind leg exists).
Descent checks can be completed as memory checks or in a flow pattern
followed by a descent check-list, as available. The type of descent checks
required may vary depending on the flight undertaken.
The following checks describe a good acronym to encompass both IFR and VFR
flight, to be carried out prior to or during the descent.
Q
One example of typical descent checks is 'Triple A-HATFIRE”:
●
●
●
A – ATIS – RECEIVED - Weather checked;
A – Aids – TUNED - Navigation and Approach Aids set/checked;
A – Approach – BRIEFED;
H – Heading – CHECKED, heading aligned/synced, track/wind
noted, heading bug set;
● A – Altitude – CHECKED, descent profile checked, MSA checked,
QNH set, altitude bug set;
● T – Time, CHECKED, noted, ETAs revised, ATAs updated, to/from
way-point, timer set;
● F – Fuel – CHECKED, correct tank (selector on both) remaining
flight time/time to diversion considered;
●
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I – Instruments – SET AND CHECKED, suction, amps,
annunciators; Icing – CONSIDERED, carb. ice/engine ice as
required
● R – Radios – SET AND CHECKED, required main and standby
frequencies set, navigation frequencies set;
● E – Engine – CHECKED, temperatures and pressures green,
electrics checked, mixture set, carb. heat, and cowl flaps closed/as
required/applicable.
●
Note: HATFIRE is also used as an en-route check as described in the Cruise
section, covering the same items, in the same way BUMPFFEL covers for after
takeoff and approach checks.
Approach
When approaching the circuit the approach (or downwind) checks are completed
to ensure the aircraft configuration is set for the approach phase.
Note: These checks are termed 'downwind' checks in light aircraft, because they
are most often performed on the downwind leg, however they are better termed
'approach' or 'pre-landing' checks as they need to be performed before landing
regardless of which leg we join the circuit on.
Q
Typical approach/downwind checks are as follows (BUMFFEL):
● Brakes – ON check pressure and ensure OFF;
● Undercarriage – FIXED/DOWN (as applicable);
● Mixture / Pitch / Power – SET;
● Flaps – as required;
● Fuel – CHECKED (on BOTH, quantity checked, primer locked,
pump off, as applicable);
● Engine’s Temperature & Pressure – CHECKED;
● Landing Light – ON.
Normal approach for landing should be made with full flaps and a speed of 6065kts, lowering the speed to 55kts when crossing threshold.
During training and for normal operations, minimum speeds are usually
increased by 5 knots to provide a bigger safety margin. In windy conditions, a
wind correction factor should also be applied increasing the safety margin again
to allow for wind shear (see the Short Field Landing section following for full
details). Once more experience on the aircraft is gained, variations to final
approach speed can be selected within the approved final approach range for
the conditions and runway.
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Carburettor heat should be applied for low power operation on approach, and
selected cold, on short final for possible go around or ground operations.
Once established on final, in the landing configuration, final approach checks
must be carried out. These comprise vital actions that must be completed before
landing or go-around.
Generally final approach checks in a single pilot operation should be completed
from memory to avoid distraction, since the aircraft is close to the ground and in
a critical phase of flight, however a control column checklist is a suitable
alternative.
Q
Typical final approach checks are as follows (CCUMP):
● Cowl Flaps – FIXED/OPEN (as applicable);
● Carb Heat – COLD (as applicable);
● Undercarriage – FIXED/DOWN (as applicable);
● Mixture – SET for go-round;
● Pitch - FIXED/FULL FINE (as applicable).
Short Field Landing
For a short field operation, an approach should be made at the recommended
minimum or short field approach speed, approximately 60kts with full flap.
Positive control of the approach speed and descent should be made to ensure
accuracy of the touchdown point. The landing should be positive, nose high and
as close as possible to the stall.
The short field approach speed allows for minimum margins above the stall, of
approximately 1.3 times the stall speed in the approach configuration.
In windy/gusty conditions, a wind correction factor should also be applied
providing a safety margin to allow for wind shear.
The rule for application of the wind and gust factor is:
Q
½ HWC and all of the gust
e.g. for a wind of 20kts gusting 30 at 60 degrees to the center-line, the HWC is
10kts and the gust is 10kts so the wind should be increased by 20kts.
Although this sounds like a large increase in speed the following must be
remembered, only head wind component must be considered and as only half is
taken there is still a reduction in distance from the reduced ground speed, as
landing calculations should be made in still wind.
Headwind component can be calculated from graphs, trigonometry or on request
from ATC.
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When the wind is gusting there is generally a significant headwind factor so
even if all gust is taken landing distance may not be significantly affected, and
whenever the wind is reported gusting, particularly at altitude we need to have
all the resources available to deal with unknown influence of wind shear,
especially with older models of C172 which have only very small amounts of
residual power available for recovery.
The rule however is a starting point and may be modified as required for
conditions and field length.
It is vital on a short field landing to have precise control of speed and height. To
do this, select a point slightly short of the aiming point, that is, the point where
the flare will start. Keep this point at a constant position on the windshield,
approximately half way between the horizon and the cowl, and maintain this
with elevator. This will ensure a constant slope, thereafter any deviation on
speed can be fixed with a positive application of power. Remember that the
changes in pitch and power need to be effected quickly and accurately so that
the deviations from speed and slope are kept small.
Crosswind Landing
When approaching to land with a crosswind the aircraft flight manual discusses
crabbed, slipping or combination method.
To prevent drift on finals the aircraft should be crabbed into wind as detailed
above. For landing, the aircraft nose should be brought in line with the runway.
In doing so, unless we can immediately touch down at that point, which is
unlikely with such a high lift wing like the C172, the aircraft will begin to drift,
and the ‘into wind’ wing has to be lowered just enough to keep the aircraft on
the runway centre line. The ‘into wind’ wheel will then make contact with the
ground first, thereafter the remaining main wheel and then the nose wheel
should be positively placed on the ground, and ailerons placed into wind to
prevent aerodynamic side forces.
Since it is impossible, or very undesirable to fly a long approach entirely slipped,
and it is impossible to land in the crabbed position, for the high lift, high wing
Cessna, the question of differing techniques is, therefore, more a question of
“where to transition?” That is where to change from the ‘crabbed’ approach into
the landing configuration.
The transition is ideally achieved in the round out, since early transition creates
both excessive drag, uses excessive pilot work load, and creates a situation
which is unbalanced flight. Additionally the side-slip (crossed controls) reduces
the amount of rudder available on the upwind side.
However, although the end point is to transition as late as possible, during the
early stages of crosswind training, the crosswind “slip” may be commenced
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much earlier, to enable students to feel comfortable with the control inputs
required before using them close to the ground.
In a strong crosswind a slightly higher approach speed may be required to
maintain more effective control against the wind factor. A slightly higher
touchdown speed is also recommended to prevent drift in the transition between
effective aerodynamic control and effective nose wheel steering.
Reduction in flap setting improves lateral stability, for improved crosswind
control. In strong crosswinds, as with crosswind takeoffs, it's recommended to
use the minimum flap required for the field length.
It should be noted the
maximum demonstrated
instructor (see further
section, under Crosswind
C172 is controllable with full flap in excess of the
crosswind, and is a good exercise to practise with an
in Maximum Demonstrated Crosswind Component
Takeoffs).
Flapless Landing
Two items of importance should be considered for a flapless landing.
1. Lack of drag to assist with the descent and approach.
2. The increased stall speed compared to the normal landing configuration.
To assist with overcoming these items a slightly lower power setting and higher
approach speed should be used. If necessary the downwind may be extended
slightly. Both the approach and round out will be flatter than for a normal
approach, and tendency to float, due to the lack of drag, is increased.
The increase in approach speed need not be more than either the recommended
approach speed without flap, or the normal approach speed with the increase in
stall speed factored in. Where field length is not a consideration, the pilot may
elect to use a higher margin, however the tendency to float must be
remembered.
In the C172 the recommended flapless approach is approximately 70-75kts.
Balked Landing (Go Round) Procedure
The procedure for a balked landing, or more commonly called, a go around, is as
follows:
1. Immediately apply full power;
2. Maintain the go around attitude, (do not allow the aircraft to pitch above
the horizon);
3. Immediately retract flap to 20 degrees;
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4. Maintain Vx until clear of obstacles;
5. Accelerate to Vy, retracting flap once above the minimum speed.
The wing flaps should be reduced to 20 degrees immediately after full power is
applied, there is no speed restriction on retraction from full flap to 20 degrees
flap.
Maintain the correct attitude, fine tuning to ensure the aircraft is neither
descending nor decelerating.
Once flaps are 20 degrees, the aircraft may be accelerated to the required climb
out speed.
Upon reaching the safe minimum retraction airspeed (60kts) and altitude
(300ft), the flaps should be retracted in stages to the full UP position, and after
takeoff checks completed.
After Landing Checks
When clearing the runway after landing, it is vital to complete the after landing
checks for engine management and airmanship considerations.
For engine handling considerations, the cowl flaps (if applicable), since there is
no cooling airflow.
At higher altitudes or temperatures, the mixture which has been set rich for the
go-around, should be leaned for taxi to prevent spark plug fowling.
The wing flaps must be retracted (to prevent ATC suspecting a hijacking has
occurred!).
It is polite to select the strobe and landing lights off.
The transponder should be selected to standby, unless otherwise dictated by
ATC procedures.
After Landing checks can be completed in a flow pattern followed by a check-list,
where available.
Q
Typical after landing checks are as follows:
● Cowl Flaps – OPEN for taxi;
● Mixture – SET for taxi;
● Flaps – UP;
● Strobes and Landing Light – OFF;
● Transponder – STANDBY.
Taxi and Shutdown
Taxi should be planned to suit engine cooling requirements when needed. If you
are operating on rough gravel remember to avoid needing to operate the aircraft
stationary at idle for prolonged periods.
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In a normally aspirated engine, providing the approach was accomplished
without using excessive amounts of power, in most cases the taxi should provide
sufficient time for cooling down the engine. For a turbo additional cooling may
be required (see more in the following section on Engine Handling Tips).
Before completing the shutdown, and after selecting all the electrical equipment
off, it is recommended to complete a dead-cut check to ensure all magneto
positions, in particular the OFF position is working, so the propeller is not left
'live'.
Shutdown again can then be accomplished in a flow pattern*, followed up with a
checklist where available.
Q
Typical shutdown checks are as follows:
● Avionics – OFF;
● Electrical Equipment (except beacon) – OFF;
● Magnetos – DEAD CUT CHECK;
● Mixture – CUTOFF;
● Magnetos – OFF;
● Master – OFF;
● Standby Battery – OFF (if applicable)
● Fuel Selector – OFF / LOW TANK;
● Control Lock – IN;
● Flight Time/Hour Metre – RECORDED;
● Tie Downs/Screens/Covers – FITTED.
*Note: The shutdown checks may be completed as a read and do checklist,
where required, since if a check e.g. avionics or the dead cut check are omitted
prior to shutdown, they cannot be redone, so it is more feasible to complete as
a read and do checklist. However, on the other hand, omission on the occasional
is not critical, and for consistency a checklist method is also satisfactory. The
method is at the discretion of the pilot or operator.
Circuit Pattern
The standard circuit pattern, unless published otherwise, is the left circuit
pattern at 1000ft above ground for piston engine aeroplanes.
The circuit pattern may differ from airport to airport. Ask your instructor, the
briefing office or consult the relevant aeronautical information publication for the
pattern on your airfield.
The circuit pattern contains all the critical manoeuvres required for a normal
flight, condensed into a short space of time. It is a great way to learn the critical
flight checks, practice manoeuvres and improve overall flying skills.
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Note: The following provides guidelines and summaries of all the checks
required during flight. Checks have been repeated here to provide a complete
study aid, to assist students in learning the procedures. Full details of each
phase are contained in the relevant parts of the preceding pages in this section.
The following summarised in-flight procedures for circuit patterns from start up
to shutdown:
Q
Complete the aircraft preflight walk around, ensuring fuel and oil
quantities are sufficient, all required equipment is serviceable, and the
condition of the aircraft and all components is acceptable for flight.
Q
Complete the passenger brief, where required, and once all are on board,
with doors closed, and seatbelts on, complete the before start flows;
Q
Once before start flows are completed, the following master off Before
Start checklist is recommended:
● Preflight Inspection – COMPLETE;
● Tach/Hobbs/Time – RECORDED;
● Passenger Briefing – COMPLETE;
● Brakes – SET/HOLD;
● Doors – CLOSED/LOCKED;
● Seats / Seatbelts – ADJUSTED, LOCKED;
● Fuel Selector Valve – BOTH/CORRECT TANK;
● Carburettor Heat – COLD (if applicable);
● Cowl Flaps – OPEN (if applicable);
● Pitch – FULL FINE (if applicable);
● Undercarraige – FIXED / DOWN (as applicable);
● Avionics – OFF;
● Electrical Equipment – OFF;
● Rotating Beacon – ON.
Q
Once ready to start with all before start items complete, and with the
standby battery armed (if applicable) and master switch ON, complete
the 'ready for start' or 'master on-Before for Start' checklist:
● Engine Instruments – CHECKED
● Electrical Instruments – CHECKED
● Annunciators – CHECKED (if applicable);
● Circuit Breakers – IN.
After completing all before start checklists, the start is then accomplished as a
procedure, since the actions are required to be carried out in a timely manner,
with prior knowledge of the actions, and cannot be read from a checklist.
Q
When the before start checklist is accomplish the Start Procedure:
● Propeller Area – CLEAR.
● Prime – AS REQUIRED (0-3 strokes, or 0-5 seconds, 6 gal/hr);
● Mixture – RICH/AS REQUIRED*;
● Throttle – SET approx ½ centimetre**;
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●
●
●
●
Starter – ENGAGE;
Throttle – 1000RPM (maximum);
Oil Pressure – RISING (within 30 seconds maximum);
Electrical System – Charging.
Q
After start, complete the after start flow, ensuring to copy the ATIS
where available, check and set all instruments, and controls. Then the
following After Start checklist is recommended:
● Mixture – SET;
● Flight Instruments – CHECKED AND SET;
● Engine Instruments – CHECKED;
● Flaps – RETRACTED/SET;
● Transponder – STANDBY/GROUND.
Q
Test the brakes as soon as possible after the aircraft begins moving, then
at any convenient time during the taxi check the flight and navigation
instruments, then complete the Taxi checklist.
● Brakes – CHECKED;
● Flight Instruments –TESTED and SET;
● Navigation Instruments – TESTED and SET.
Q
Taxi towards the runway and position the aircraft clear of the runway to
carry out the Engine Run-up and pre takeoff checks. Ensure that:
● The slipstream will not affect other aircraft;
● A brake failure will not cause you to run into other aircraft or
obstacles;
● Loose stones will not damage the propeller.
Q
Prior to the Engine Run-up it is important to check the following items:
● Confirm fuel is on correct tank (always run up on the tank you
intend to takeoff;
● Check the mixture is set correctly for the run-up;
● Check temperatures and pressures in the green range.
Q
Set the park brake and complete the Engine Run-up
● Power – Set 1700rpm or 1800, as required by the model;
● Mixture – Set for elevation (above 3000ft density altitude);
● Magnetos – Check left, both, right, both, confirm smooth
operation within limits for drop and differences;
● Pitch – (if applicable) Cycle three times for a cold engine,
minimum once if the engine has bee running.
● Engine’s Temperature & Pressure – Check;
● DI – Aligned with compass;
● Power – reduce to idle, confirm steady at 500-700rpm, return to
1000rpm.
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Q
Complete the Pre Takeoff Vital Actions checks. One of the most
popular acronyms (Too Many 'Pilots Go Fly In Heaven Early) is detailed
below:
Too
Many
Pilots
Go
Fly
In
Heaven
Early
Trims and flight controls – tested and set;
Mixture set for takeoff;
Magnetos on both;
Pitch full fine (as applicable);
Gills (Cowls) open / fixed (as applicable);
Gyros uncaged (as applicable) and set;
Fuel contents checked, selector on correct tank,
primer locked, fuel pump off;
Flaps set for takeoff;
Instrument panel check from right to left, DI aligned
with compass, altimeter set, clock check, navigation
instruments set for departure, autopilot off;
Hatches and harnesses secure;
Electrics checked, circuit breakers checked, systems
checked.
Q
After completing both run-up and pre-takeoff flows, a Before Takeoff
checklist should be carried out, for example:
● Run-up – COMPLETE;
● Trim – TESTED and SET for takeoff;
● Flight Controls – CHECKED, AUTOPILOT OFF;
● Flight Instruments – CHECKED and SET;
● Flaps – SET for takeoff;
● Fuel – CHECKED (on BOTH, quantity checked, primer locked,
pump off, as applicable);
● Mixture/Pitch/Power – CHECKED*/SET;
● Departure Brief – COMPLETE.
Q
Consider air traffic control and radio procedures before lining up on the
runway. Line up and ensure that the nose wheel is straight (make full use
of the runway length available) and perform the Line-Up Checks
(REmember What To Do Last), followed by a line up checklist.
● Runway – CLEAR (Unobstructed, correct runway);
● Engine Temperatures and Pressures – CHECKED/GREEN;
● Windsock – CHECKED direction and strength (confirm against
reported wind), position control column accordingly;
● Transponder ALT (TA/RA or ON as applicable);
● DI – ALIGNED with compass and reading correct runway heading;
● Landing Light and Transponder – ON.
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Q
Q
Q
Q
Q
Q
Q
Q
Q
Q
Q
Q
Takeoff and climb maintaining runway alignment. Keep straight with
rudder (will require right rudder due to the slipstream and torque
effects). Reduce frictional drag, and protect the nose-wheel by holding
the weight of it.
Upon reaching a safe altitude (300’ above airfield elevation) raise the
flaps (if used) and perform After Takeoff Checks (BUMFFEL):
Typical after takeoff checklist is as follows (BUMFFEL):
● Brakes – CHECK – apply, check pressure and off;
● Undercarriage – FIXED/UP;
● Mixture / Pitch / Power – SET for climb;
● Flaps – UP;
● Fuel – CHECKED (on BOTH, quantity checked, primer locked,
pump off, as applicable);
● Engine’s Temperature & Pressure – CHECK;
● Landing Light – OFF / AS REQUIRED.
At a minimum of 500’ scan the area into which you will be turning, select
a reference point slightly ahead of the wing-tip (in the case of a
headwind) and then turn onto crosswind leg using a normal climbing turn
(maximum bank 15 degrees or Rate 1).
Reaching circuit height, level-off, allow the speed to settle, set downwind
power, approx 2300rpm, and trim the aeroplane for straight-and-level
flight.
Scan the area into which you will be turning and turn onto downwind leg,
selecting a reference point well ahead, on which to turn to, to parallel the
runway.
Circuit width should be approximately 1½ to 2 miles from the runway.
When abeam the runway, make ATC call and perform Pre-landing
Checks (BUMFFEL):
● Brakes – CHECK – Apply, check pressure, and off;
● Undercarriage – FIXED/DOWN;
● Mixture / Pitch/ Power – SET;
● Flaps – As required;
● Fuel valve – ON, correct tank, sufficient;
● Engine’s Temperature & Pressure – CHECK;
● Landing light – ON.
Just before base leg (45° to the runway), check that speed not exceeding
Vfe and lower flap to 10°.
After scanning for traffic on base and final, turn base leg performing
standard medium turn to the left.
After levelling the wings, select Carb. Heat on, reduce power to 1700
RPM (while keeping the nose up for the approach speed), lower the flaps
to 20° and commence descent.
Trim the aeroplane to maintain approximately 65-70kts and use power to
maintain the desired approach angle.
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Q
Q
Q
Q
Q
Visually check the final approach clear of traffic and anticipate the turn to
final so as to roll out with the aircraft aligned with the direction of the
landing runway and no less then 500’.
Lower the flaps to the full position and complete Before Landing Check
(CCUMP):
● Cowl Flaps – OPEN;
● Carburettor Heat – COLD;
● Undercarriage – DOWN/FIXED;
● Mixture – SET for go around power;
● Pitch – FULL FINE (as applicable).
Execute the appropriate landing procedure.
Maintain the centre line during the landing run by using rudder and wings
kept level with aileron. Brakes may be used once the nose-wheel is on
the ground.
Once clear of the runway, stop the aeroplane, set 1000rpm and complete
the after landing flows and After Landing Checks:
● Flaps – UP;
● Cowl Flaps – OPEN;
● Carburettor heat – COLD;
● Mixture – SET for taxi;
● Strobes and Landing Light – OFF;
● Transponder – STANDBY/GROUND – as required.
Note: single pilot operations may prohibit safe checklist use in flight, however
where feasible, all airborne checks should be followed by an appropriate
checklist.
Q
Q
Taxi to the parking bay, perform shut down checks and complete the
shutdown checklist.
Typical Shutdown checks are as follows:
● Avionics – OFF;
● Electrical Equipment (except beacon) – OFF;
● Magnetos – DEAD CUT CHECK;
● Mixture – CUTOFF;
● Magnetos – OFF;
● Master – OFF;
● Standby Battery – OFF (if applicable)
● Fuel Selector – OFF / LOW TANK;
● Control Lock – IN;
● Flight Time/Hour Metre – RECORDED;
● Tie Downs/Screens/Covers – FITTED.
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Circuit Profile
On the following pages the circuit profile can be seen. Note, this may differ from
airport to airport. Different techniques are also possible, to achieve the same
result.
It is important to remember, that the descent for approach will begin
approximately 300ft per nm from the threshold, i.e. 3nm for a 1000ft circuit.
Ideally speeds should be selected for approach at reducing intervals starting
with a speed slightly below the flap limiting speed, and reducing to Vbug or Vref,
that is, the desired final approach speed.
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Circuit Profile – Normal Circuit
Late downwind:
2000rpm, 80kts level
4
+/-
1700rpm, 10 deg, 80kts
descending
At 1000ft AGL,
Maintain level,
approx 2350rpm, 95kts
+/-1.5nm
eg
5d
Begin
descent
Approx
3nm from
touchdown
Complete prelanding checks
and downwind
radio call
Base:
1700rpm,
20 deg, 75kts
>300ft AGL
complete after
takeoff checks
Final:
1700rpm, 30 deg, 75kts
>500ft AGL, DER
turn crosswind
Climb out:
Vy approx 70-75kts
Complete final checks and
radio call
Circuit Profile – Maximum Performance (Differences)
4
+/-
1700rpm, 10
deg,Vref+10kts
descending
At 1000ft AGL,
Maintain level, approx
2350rpm, 95kts
+/-1.5nm
eg
5d
Begin
descent
Approx
3nm from
touchdown
Late downwind:
2000rpm, 80kts level
Base:
1700rpm,
20 deg, Vref+5kts
Release brakes;
Elevator
tail low
Final:
1700rpm, full flap, Vref
(Short field 60kts minimum
approach speed)
Full power
against brakes,
ensure
minimum
static rpm
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OCA: Accelerate,
raise gear/flaps
(as applicable)
Climb out:
Before OCA
Vx or Vx F10
Maintain Vy to
1000ft
(flap differs with model)
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Note on Checks and Checklists
Current recommended operating practices on a single-pilot aeroplane dictate use
of a checklist AFTER completion of vital actions in a flow pattern on each critical
stage of the flight, such as before and after takeoff, on downwind and final legs.
This emanates the tried and true method developed in the airline industry, called
“challenge-response”, for two crew, or “read-respond” for one person checklists.
The acronyms suggested in the preceding paragraphs provide a memory aid to
allow for completion of the checks prior to reading the checklist. For single pilot
operations on light aircraft, acronyms are strongly recommended for memory
items and flows. Any convenient acronym is acceptable providing the required
items are catered for.
Unless you only ever intend flying one type, it is also recommended to use
generic memory items. This will avoid potential omissions when flying different
types.
Although flows, acronyms, and memory items are preferably as generic as
possible, a checklist, often referred to as an “operator” checklist, should not be.
A checklist should ideally be specific, not just to the type of aircraft, but to the
specific serial number, and the operation. This is important to avoid unnecessary
checks which cause complacency, and to avoid missing critical aircraft/operator
dependent checklist items.
A checklist does not normally mimic the memory flows, as there may be items in
the flows that are normal crew actions and not considered part of a checklist, for
example light selections, power settings, headings, will not normally not be on a
checklist.
When a checklist is completed in single pilot operations and no autopilot is
available, the checklist should be as hands-free as possible, especially for critical
phases. Control column checklists, or a chart clip on the control yoke, are
considered the easiest method to achieve this.
The above checks and procedures are based on standard training practices.
Application of these checks and development of a checklist for operational use,
must be cross referenced against the POH of the aircraft you are flying, and the
applicable regulations.
Some examples of checklists, in printable and document format, free for
download and editing, can be found at http://www.redskyventures.org.
Action-Lists
An 'action-list' or a 'read-and-do list' is a type of checklist where actions are
completed as they are read. An action-list omits the redundancy built in to a
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normal check-list procedure since items are only done once, not first actioned
then checked.
This type of procedure is sometimes used for completion of normal checks in abinitio training operations and light aircraft training, to simplify processes when
students are learning. It may also be suitable for private pilots who do not fly
often. Ideally, action-lists should only be used for their intended applications, in
emergencies/abnormalities and non-standard operations.
In non-standard operations, an action-list is preferred, since the procedures are
seldom carried out, and are too unfamiliar for completion from memory.
In emergencies, an 'action-list' follows completion of the emergency memory
items. Memory items are restricted to the immediate time critical actions, to
avoid relying entirely on memory. Thereafter the POH 'action-list' is completed.
This method is preferred again due to unfamiliarity of the procedures, the
unsuitability to a normal check-list procedure, and due to the stressful nature of
an emergency situation.
In the later model Cessna POHs and in the the Cessna quick-referencehandbook which is provided with post 1996 models, the manufacturer
recommended memory items are written in bold typeface.
In normal operations although an action-list is better than no check-list at all, a
proper 'checklist', completed after the actions, when trained properly on
checklist operations, is far safer and more efficient.
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ABNORMAL AND EMERGENCY PROCEDURES
The main consideration in any emergency should be given to flying the aircraft.
Primary attention should be given to altitude and airspeed control and thereafter
to the emergency solution. Rapid and proper handling of an emergency will be
useless if the aircraft is stalled and impacts the ground due to loss of control.
This is most critical during takeoff, approach and landing, when the aircraft is
close to the ground.
The check lists in this section should be used as a guide only. The emergency
checklist and procedures for your particular aircraft model specified in the
aircraft Pilots Operating Handbook should be consulted for operational purposes.
Emergency During Takeoff
An emergency during takeoff, is usually defined as an engine failure or
emergency prior to reaching 1000ft above ground, where, for example the
forced landing or glide approach procedure would apply.
An emergency during takeoff can be further broken down into three scenarios,
an emergency before rotation, an emergency airborne with runway available,
and an emergency with no runway available.
Takeoff Emergency Briefing
The takeoff emergency briefing briefs specifically for an emergency during
takeoff, as described above.
The purpose of the briefing, is to consider the runway in use, and the climb-out
area, in consideration of the three scenarios. For example with a long runway, it
is always best to stop prior to rotation for all abnormalities, whereas on a short
runway it may be better, say for an alternator failure, to continue the takeoff
and re-circuit to land. Likewise for an emergency with no runway left, if there
are obstacles or built up areas on the climb out, a briefing may include
avoidance of this area after an engine failure. The briefing should always include
the glide speed, reinforcing the importance of lowering the nose for a glide.
A takeoff briefing card may be used as a prompt for the briefing, if so use key
points rather than phrases. Remember, it is best to brief in your own words,
since it is important that it's clear to you, the pilot, what you are going to do,
rather than rattle off a verbatim account of someone else's briefing.
Engine Failure Prior to Airborne and with Runway Remaining
Any emergency or abnormality during takeoff calls for the takeoff to be aborted.
The most important thing is to stop the aeroplane safely on the remaining
runway.
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For an abnormality, after the aircraft is airborne, re-landing should be
considered only if sufficient runway is available for this purpose, and if adequate
training is carried out in this procedure. As a general rule, the runway is
sufficient, if the end of the runway can be seen in front of the aircraft.
Alternatively it is usually safer to re-circuit. A low level precautionary circuit may
be completed to expedite the landing, if required.
For an engine failure or fire after takeoff, where runway length permits, it is
always best to land back, as the airport is the safest place for an emergency
landing. If no sufficient runway is available, the engine failure after takeoff
procedure should be followed.
Once on the ground, safely stopped, a decision should be made to vacate the
aircraft or to exit the runway. Where there is a fire risk, secure the aircraft by
selecting fuel, mixture, ignition, and master off, and vacate the aircraft, as soon
as possible. If not, where possible, exit the runway at the first suitable exit.
Engine Failure After Takeoff
The recommended engine failure after takeoff
60kts with flaps down (this varies with
recommended speed is sometimes higher to
handling, however this speed corresponds to the
speed is 65kts with flaps up,
model). The forced landing
provide a safety margin for
best glide speed.
Prompt lowering of the nose to maintain airspeed and establish a glide attitude
is the first response to an engine failure after takeoff. Landing should be planned
straight ahead and within approximately 30° to either side. The turn, if required,
should be made with no more than 15° of bank.
The check-list procedures assume that adequate time exists to secure the fuel
and ignition system prior to touchdown.
Any attempt to restart the engine depends on altitude available. A controlled
descent and crash landing on an unprepared surface is more preferable to
uncontrolled impact with the ground in the attempted engine start.
Just before the landing:
Q
Airspeed – 60kts with wing flaps down and 65kts with flaps up
This speed gives the best gliding distance with a propeller windmilling and flaps in up position.
Q
Mixture – IDLE CUT-OFF
Q
Fuel selector – OFF;
This will ensure that the engine will be cut-off from the fuel system
and thus minimise fire possibility after an impact.
Q
Ignition switch – OFF;
Q
Master switch – OFF
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Q
The master switch should be switched off after the flaps being set in
the desired position, to minimize the chance of a fire after
touchdown.
Doors - UNLOCKED
The doors should be unlocked in aid of rapid evacuation after the
touchdown.
After landing:
Q
Stop the aeroplane;
Q
Check that fuel, ignition and electrics are OFF;
Q
Evacuate as soon as possible.
Gliding and Forced Landing
For a forced landing without engine power a glide speed of 70kts with flaps up
and 65kts with flaps down should be used (note this varies with model).
This is the specified speed for a forced landing without power in the POH,
however it is slightly higher than the best glide speed. The higher speed allows
for increased performance in case of deviation below planned speed and
provides more penetration into wind over a longer distance. Where best range is
required the best glide speed should be flown.
During a forced landing:
Q
The first priority is to establish the glide speed and turn toward the
suitable landing area.
Q
A mayday call should be made before too much time or height is
lost, but keep it brief, you can return to the emergency
communication once the problem is dealt with;
Q
While gliding toward the area, an effort should be made to identify
the cause of the failure.
Q
An engine restart should be attempted as shown in the checklist
below.
Q
If the attempts to restart the engine fail, secure the engine and
focus on completing the forced landing without power.
Q
Ensure the Emergency communication is complete, and passengers
adequately briefed;
Q
Further attempts to restart distract the pilot from performing the
forced landing procedure.
Q
If the cause of engine failure is a mechanical failure or fire, the
engine should be secured immediately and no restart should be
attempted.
If the failure is partial, resulting in reduced or intermittent running, it is
recommended to use the partial power till arrival overhead the intended area of
landing. Then reduce to idle power and commence with the forced landing
procedure. If a partial power setting is used and power is lost or suddenly
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regained during the forced landing circuit, this may change the gliding ability of
the aircraft so dramatically, that it will be impossible to reach the intended
landing area safely.
Forced landing initial actions:
Q
Trim for 70kts with wing flaps up and 65kts with flaps down;
Q
Carb. heat on;
Q
Select a field, plan the approach.
Finding the fault:
Q
Carb. Heat – PULL (if applicable;
One of the main causes of an engine failure can be carburettor ice.
By applying the Carb. heat, the problem can be eliminated. This
action needs to be done immediately while the engine still has
sufficient heat, cooling from relative airflow during flight happens
very quickly.
Q
Fuel Pump - ON (if applicable);
In fuel injected engines, as with Carb. Ice, vapour locks are the
most common causes of engine failure, especially in hot and high
conditions, this also needs to be actioned quickly to provide the best
chance of a restart.
Q
Mixture – FULLY RICH;
Mixture is recommended to be set rich in the pilots operating
handbook, however if it is suspected the cut is from too rich setting
at altitude, leaning can be opted for.
Q
Fuel selector – CHECK ON;
Q
Throttle – INCREASE;
Q
Ignition – CHECK LEFT-RIGHT-BOTH;
Q
Primer – IN AND LOCKED (if applicable).
Securing the engine:
Q
Mixture – IDLE CUT-OFF;
Q
Fuel selector – OFF;
This will ensure that the engine will be cut-off from the fuel system
and thus minimise fire possibility after an impact.
Q
Throttle – FULLY FORWARD;
By opening the throttle all the fuel left in the carburettor will be
sucked out, and the fire possibility will be minimised.
Q
Ignition switch- OFF;
Q
Doors - UNLOCKED.
The doors should be unlatched in anticipation of a evacuation after
the touchdown, and to avoid entrapment in case of fuselage
damage. After landing the same procedure as detailed for an engine
failure after takeoff above, should be initiated.
Q
Master switch – OFF;
The master switch should be switched off, after the flaps are set for
landing (for electric flaps), to minimize an electrical fire.
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In case of simulated forced landing training, during an extended glide, select
partial power for a brief period every 500-1000ft to provide engine warming and
to ensure power is still available. Keep the nose down to maintain the glide
angle.
Engine Fire
In case of fire on the ground, the engine should be shut down immediately and
fire must be controlled as quickly as possible. In flight such emergency calls for
execution of a forced landing. Do not attempt to restart the engine.
The pilot may initiate a side-slip to keep the flame away from the occupants.
This procedure can be also used to extinguish the fire.
If required, the emergency descent may be initiated to land as soon as
possible. Opening the window or door may produce a low pressure in the cabin
and thus draw the fire into the cockpit. Therefore, all doors and windows should
be kept closed till short final, where the door should be open in anticipation of a
quick evacuation after the landing.
An engine fire is usually caused by fuel leak, an electrical short, or exhaust leak.
If an engine fire occurs, the first step is to shut-off the fuel supply to the engine
by putting the mixture to idle cut off and fuel valve to the off position.
The ignition switch should be left on and throttle fully open in order for the
engine to use the remaining fuel in the lines and carburettor.
The following check list should be used in quick and proper manner.
During an engine start on ground:
Q
Cranking – CONTINUE FOR A FEW MINUTES
This will suck the flames through the carburettor into the engine.
The fire may burn out of exhaust for a few minutes and extinguish if
continue cranking.
Q
If engine starts - power – 1700rpm FOR A FEW MINUTES;
Q
Mixture – IDLE CUT OFF
Q
Fuel valve – CLOSED
Q
Ignition switch – OFF
Q
Master switch - OFF
Use the fire extinguisher if the fire persists. Do not restart and call
for maintenance for the engine inspection.
In flight:
Q
Mixture – IDLE CUT-OFF
Q
Fuel valve – OFF;
Q
Throttle – FULLY OPEN;
Q
Master switch – OFF;
Q
Cabin Heat and Air – OFF (To prevent the fire to be drawn into the
cockpit);
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Q
Q
Airspeed – 85kts, if the fire is not extinguished, increase to a glide
speed which may extinguish the fire;
Forced landing – EXECUTE.
Electrical Fire
The indication of an electrical fire is usually the distinct odour of burning
insulation. Once an electrical fire is detected, attempt to identify the effected
circuit and equipment. If the affected circuit cannot be identified or isolated,
switch the master switch off, thus removing the possible source of the fire. If the
affected circuit or equipment is identified, isolate the circuit by pulling out the
applicable circuit breaker and switching the equipment off.
Smoke may be removed by opening the windows and the cabin air control.
However, if the fire or smoke increases, the windows and cabin air control
should be closed. The fire extinguisher may be used, if required. Ventilate the
cockpit after that to remove the gases. Landing should be initiated as soon as
practical on the first suitable airfield. If the fire cannot be extinguished, land as
soon as possible.
Rough Running Engine
A rough engine running can be caused by a number of different reasons, faults
that can be dealt with from the cockpit include spark plug fouling, magneto
faults, fuel vaporisation, engine-driven fuel pump failure, and blocked air intake,
see the relevant sections regarding these faults. Engine faults will be associated
with changes in oil pressure and temperature – see these sections for further
details, although in this case the fault cannot be fixed, the situation can be
managed to achieve the most desirable outcome.
Magneto Faults
A sudden engine roughness or misfiring is often an indication of a magneto
fault. Switching from BOTH to the L or R position will confirm if one magneto is
faulty, and identify which one.
In this situation, take care with switching from L to R position, as if one
magneto has grounded or failed completely, no change will occur when selecting
the working magneto and a complete power loss will occur when the failed
magneto is selected.
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Spark Plug Faults
A slight engine roughness can be caused by one or more spark plugs becoming
fouled. This often occurs during prolonged operation at low power settings with
the mixture set too rich, and commonly happens at high density altitudes during
taxi, well below 3000ft pressure altitude where Cessna recommends leaning the
mixture.
Switching to one magneto can normally isolate the problem, as running the
cylinder on one plug will cause misfiring on the cylinder that contains the faulty
plug. (This is the same procedure used when an excessive magneto drop or
rough running is experienced during the engine run-up prior to departure). As
with magneto faults, care should be taken when applying this procedure inflight, as if fouling is severe enough to affect more than one cylinder, it is
possible that there could be a severe loss of power or engine cut when switching
to one plug.
If the fault is due to fouling, leaning the mixture to peak or just rich of peak and
running at a moderate power setting for a few minutes to burn off the excessive
carbon should fix the problem. Note that it is not recommended to operate at
peak with more than 55% power, however there may be cases where more
power is needed, care should be taken to monitor the cylinder temperatures.
If the problem persists after several minutes operation at the correct mixture
setting, it is likely to be caused by a faulty spark plug which must be replaced.
Continue to operate on BOTH, or if extreme roughness dictates selection of the L
or R position, select the L or R magneto and continue to the nearest suitable
airfield.
Abnormal Oil Pressure or Temperature
Low oil pressure, which is not accompanied by high oil temperature, may
indicate a failure of the gauge or the relief valve. This is not necessarily cause
for an immediate precautionary landing, but a landing at the nearest suitable
airfield should be planned for inspection. The situation should be closely
monitored for any changes.
Complete loss of oil pressure, accompanied by a rise in oil temperature is good
reason to suspect an engine failure is imminent. Select a suitable field for a
precautionary or forced landing. Reduce engine power as far as possible and
plan to use minimum power for the approach, preferably plan a glide approach
to allow for continuation in the event of a complete engine failure.
A small reduction in oil pressure with a rise in temperature is normal, since the
viscosity of the oil will change as the temperature increases.
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Any increase in oil temperature and reduction in oil pressure without a clear
cause, is a sign of an impending engine problem. Attempts must be made to
reduce the oil temperature and demands on the engine. Provisions should be
made for the situation getting worse, adjust track towards areas more suitable
for a forced landing, and consider suitable airfields for diversion or to complete a
precautionary landing.
High engine temperatures which result from operations, for example during an
extended climb, or prolonged operations at high power in high ambient
temperatures, must also be monitored, and attempts to increase cooling or
reduce power should be made, for example level off at an intermediate altitude,
richen mixture, ensure cowl flaps (if installed) fully open.
Carburettor Ice
Carburettor ice can be experienced during low rpm operation, but may also be
experienced at normal cruise in the right conditions of humidity and
temperature.
Carburettor ice will form more readily at humidities above 50% and
temperatures from -10 to +25 degrees Celsius. In these conditions it is
recommended to regularly apply carb. heat for several seconds to prevent ice
build up before the effects of loss of performance are felt. This action can be
included with the cruise checks, every 15 minutes.
At temperatures approaching -10 and below, use of carb. heat can increase the
temperature into the freezing range, and should be only used if icing is
suspected. Carb. heat should not be used above 75% power, since it is
extremely unlikely to experience carburettor ice at these power settings, and
the loss of power and additional heat are detrimental to the high engine
demands.
The symptoms of carburettor ice build up are rough running and/or a drop in
rpm, severe icing may cause a complete power loss. Carburettor ice can be
removed through immediate application of carburettor heat, by pulling the carb.
heat knob out. If there is icing, application of carb. heat may initially make the
situation worse, as the ice breaks away and is ingested. Avoid the temptation to
close the carb. heat again, as this is normally a sign the ice is clearing.
Since the heated air causes a richer air/fuel mixture, the mixture setting may
need to be readjusted if the carburettor heat is required to be used for any
prolonged period, for example in a long low power descent. Remember to richen
the mixture again prior to closing the Carb. heat.
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Stalling and Spinning
The stall characteristics are conventional for flaps retracted and extended. The
stall warning is indicated by a steady audible signal 10kts before the actual stall
is reached and remains on until the flight attitude is changed.
The aerodynamic stall warning (buffet) is not pronounced, only a slight elevator
buffeting may occur just before the stall, combined with sink, and a forward
pitching moment, as the lift reduces and the centre of pressure moves aft. The
stall characteristics and the tendency to drop a wing will be far more
pronounced with flap down and power on.
A positive wing drop may occur if the aircraft is unbalanced prior to a stall, or
can be induced by the use of power/flap and/or unbalanced flight on the entry to
the stall.
Spin characteristics are conventional. To enter the spin, full rudder should be
applied about 10kts before stall and stick held fully back. The throttle should be
closed on spin entry. Recovery is standard – ensure throttle is closed, ailerons
neutral, simultaneously apply rudder to stop the spin, and pitch forward to break
the stall, then ease out of the resulting dive, apply power to assist in regaining
height loss once speed begins decreasing.
Spinning is only permitted in the utility category, with a lower takeoff weight and
restricted Centre of Gravity locations.
Intentional spins with flaps extended are prohibited, this is mainly because the
high speed which may occur during recovery is potentially damaging to the
flaps/wing structure.
Fuel Injection Faults
The following faults apply to fuel injected engines only.
Engine Driven Fuel Pump Failure (Fuel Injected Models)
An engine driven pump failure can be identified by a sudden drop in fuel
pressure, followed by a loss of power, while operating from a fuel tank with
adequate fuel supply. (Note – a similar indication will occur with fuel starvation).
However at cruise power setting it may not be noticeable as gravity flow will
sustain engine operation.
Following any power loss, immediately select the auxiliary fuel pump on, to reestablish fuel flow. If either engine pump failure or vaporisation is the cause this
will usually alleviate the problem.
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For split rocker fuel pumps, the auxiliary fuel pump is held in the spring loaded
'HI' position to re-establish flow at high power settings, select the 'LO' position
for cruise and approach. Where the auxiliary fuel pump has only one position,
select the fuel pump on when required (by engine failure or fluctuations).
During cruise and low power operation, the gravity flow should be sufficient to
maintain engine operation, however at high power, or any time there is engine
or fuel pressure fluctuations, the fuel pump should be selected on.
Plan to land at the nearest suitable airfield.
Excessive Fuel Vapour (Fuel Injection Models)
Significant problems have occurred on Cessna single engine series with fuel
surges caused by fuel vaporisation, often leading to engine failures and forced
landings. This problem is worst with high ambient and high engine operating
temperatures.
The Cessna POH recommends, under the title “Excessive Fuel Vapor”, a fuel
stabilisation procedure to use when fuel flow fluctuations of “1Gal/hr or more or
power surges” occur. Initial actions require turning on the fuel pump, resetting
the mixture, and changing tanks if problems continue.
Selecting the fuel pump on should solve the problem, however in some models,
due to the excess fuel return routing, changing tanks may be required before
the problem is solved. Models C172K and earlier require a change of tank, from
both onto left or right, when operating above 5000ft in the cruise, to prevent
fuel vaporisation problems. Although more prevalent in these models, the same
situation can occur in any model, due to the system design, or due to a nonreturn valve fault in the excess fuel return line. Which is why selecting an
alternative tank is part of the recommended procedure for fuel vaporisation
faults. See more under Fuel Selector, in the Fuel System Section.
Landing Gear Emergencies (RG model)
The following section applies to retractable models only.
Landing gear malfunctions, in most cases, are a non-normal situation where
time is not critical. Therefore, landing gear emergencies should not be addresses
in the circuit, but rather somewhere away from conflicting traffic and while
maintaining a safe altitude.
The manual gear extension procedure should be completed with reference to the
checklist from the Pilots Operating Handbook, as it is an abnormal procedure, to
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ensure all steps are completed correctly. An example of the POH procedure is
provided below.
Normal landing gear extension time is approximately 5 seconds. If the landing
gear will not extend normally, the general checks of circuit breakers and master
switch shall be performed and the normal extension procedures at a reduced
airspeed of 100KIAS repeated.
The landing gear lever must be in the down position with the detent engaged. If
efforts to extend and lock the gear through the normal landing gear system fail,
providing there is still hydraulic system fluid in the system, the gear can be
manually extended by use of the emergency hand pump. The hand pump is
located between the front seats.
If gear motor operation is audible after a period of one minute following gear
lever extension actuation, the GEAR PUMP circuit breaker must be pulled out to
prevent the electric motor from overheating. In this event, remember to reengage the circuit breaker just prior to landing.
Landing Gear Fails to Retract
1.
2.
3.
4.
5.
6.
Master Switch -- ON.
Landing Gear Lever -- CHECK (lever full up).
Landing Gear and Gear Pump Circuit Breakers -- IN.
Gear Up Light -- CHECK.
Landing Gear Lever -- RECYCLE.
Gear Motor -- CHECK operation (ammeter and noise).
Landing Gear Fails to Extend
1. Master Switch .-- ON.
2. Landing Gear Lever -- DOWN.
3. Landing Gear and Gear Pump Circuit Breakers -- IN.
4. Emergency Hand Pump--EXTEND HANDLE, and PUMP (perpendicular to
handle until resistance becomes heavy -- about 35 cycles).
5. Gear Down Light -- ON.
6. Pump Handle - - STOW.
Gear Up Landing
1.
2.
3.
4.
5.
6.
7.
Landing Gear Lever -- UP.
Landing Gear and Gear Pump Circuit Breakers -- IN.
Runway -- SELECT longest hard surface or smooth sod runway available.
Wing Flaps -- FULL once on final approach (for minimum touchdown speed).
Airspeed – MINIMUM SAFE APPROACH SPEED.
Doors -- UNLATCH PRIOR TO TOUCHDOWN.
Avionics Power and Master Switches -- OFF when landing is assured.
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8. Touchdown -- SLIGHTLY TAIL LOW.
9. Mixture -- IDLE CUT-OFF.
10. Ignition Switch -- OFF.
11. Fuel Selector Valve -- OFF.
12. Aircraft -- EVACUATE.
Landing Without Positive Indication of Gear Locking
1.
2.
3.
4.
Before Landing Check -- COMPLETE.
Approach -- NORMAL (full flap).
Landing Gear and Gear Pump Circuit Breakers -- IN.
Landing -- TAIL LOW as smoothly as possible.
Where landing is safe:
5. Braking -- MINIMUM necessary.
6. Taxi -- SLOWLY.
7. Engine -- SHUTDOWN before inspecting gear.
In the event of a collapse or partial collapse on landing:
8. Mixture -- IDLE CUT-OFF.
9. Ignition Switch -- OFF.
10. Fuel Selector Valve -- OFF.
11. Aircraft -- EVACUATE.
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CESSNA 172 TRAINING MANUAL
PERFORMANCE
The following figures are given as an overview of the Cessna 172 performance.
The figures provided are an average and will not match every model of C172.
Some variations have been noted.
 It is important to refer to the approved flight manual for the aircraft you are
flying for the correct performance information before and during flight.
Specifications and Limitations
Performance figures given at 2300lbs (MAUW) and speeds in KIAS unless
specified otherwise.
Structural Limitations
Gross weight (take-off and landing)
C172, C172A, C172B
C172D through C172N
C172P
C172Q
C172R, C172S
C172RG
R172K
2200lbs
2250lbs
2300lbs
2400lbs
2550lbs
2650lbs
2550lbs
Seaplane models (All)
2220lbs
Baggage allowance (forward area)
Baggage allowance (aft area if applicable)
Baggage allowance (max. area 1 and 2)
Flight load factor (flaps up)
Flight load factor (flaps down)
120 lbs (54kgs)
50 lbs (23kgs)
120 lbs (54kgs)
-1.52g to +3.8g
0 to +3.0g
normal,
normal,
normal,
normal,
1950lbs
2000lbs
2100lbs
1950lbs
utility
utility
utility
utility
Speeds
Never Exceed Speed (Vne)
151 to 160kts (red line)
Maximum structural speed (Vno)
122 to 128kts (top of green arc)
Maximum flap speed (Vfe)
85 kts (top of white arc)
Maximum flap speed 0 to 10 degrees
110 kts (-1979 and later)
Stall speed clean/cruise configuration (Vs)
47 kts (bottom of green arc)
Stall speed in landing configuration (Vso)
41 kts
Maximum demonstrated crosswind component 15 kts
Maximum maneouvering speed (Va)
2300lbs 97 kts
1950lbs 89 kts
1600lbs 80 kts
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Speeds for normal operation
Normal take-off climb out speed
Short field take off
Short field takeoff (after 19xx
Best angle of climb speed (Vx)
60-70 kts
lift off 50ft, 50ft 60kts
Best rate of climb speed (Vy)
Normal approach flaps 30°
Normal approach flaps up
Short field landing
(Vref)
60kts flaps up (1980 and earlier)
56kts flap 10 (1981 and later)
73-67 kts, sea level to 10,000ft
55-65 kts
60-70 kts
60 kts
Speeds for emergency operation
Engine Failure after take-off
Forced landing
Precautionary landing
65 kts flap up, 60 flap down
70 kts flap up, 65 flap down
60 kts full flap
Cruise Performance*
Cruise at 2000ft pressure altitude
Cruise at 10,000ft pressure altitude
2300 rpm 105 KTAS, 6.3 gph
2300 rpm 101 KTAS, 5.6 gph
*Cruise figures provided from the pilots operating handbook should be used
with a contingency factor, a block cruises speed and fuel flow that allows for
contingency and climb and descent are normally applied.
Ground Planning
Provided below is an example for completion of your ground planning. Blank
forms can be obtained from C172 POH and a flying school.
In this example, the aeroplane needs to carry two pilots, 20 pounds of baggage,
and sufficient fuel to fly 1.5 hours en route at 8000ft on a private flight under
visual flight rules.
Route Planning
The first step in any flight planning is to determine the route, this is normally
carried out on a Nav. Worksheet, then transferred to the Flight Log for use in
flight.
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An example of a Nav. Worksheet is shown below.
FM
TO
Alt
Temp
W/V
IAS
TAS
Trk T
V
Trk M
G/S
Dist
EET
TOTALS
Fuel Planning
The next step in ground planning after completion of the navigation log or after
determination of the flight time, is to calculate the fuel required. How much load
you can carry is dependent, first, on the minimum required fuel.
On the following page page you will find example of CRUISE PERFORMANCE
table from C172 POH (Figure 5-7). The table in this book should be not used for
flight planing, use the same table in the POH of the aircraft you are flying.
For the flight we will use an outside temperature of 20ºC above standard
temperature, or -1 degrees Celsius at 8000ft. At 55% of power we should obtain
a TAS of 108 kts and a fuel consumption of 6.2 gallons per hour. Using the
conversion factors given in the beginning of this manual 1USG = 3.785Lt we
will in theory achieve 24 litres per hour fuel consumption. This figure is however
in ideal conditions with the engine and airframe producing exactly the
performance it achieved during testing.
To allow for power variations in climb and provide a more conservative approach
a “block“ figure of 30 litres per hour may be used for planning purposes.
Multiply this figure by the flight time, and for a 1.5 hour flight we will require 45
litres of fuel.
Fill in the fuel planning sheet as follows:
• On the first line enter this amount in the Fuel planning table as en route fuel;
• On the second line enter 10% of this amount as contingency fuel;
• Enter 45 minutes, at the block consumption of 30 lt/hr, for VFR reserve.
Adding together all of the above, we find the minimum fuel required for the
flight is 83 litres.
This is minimum usable fuel, the fuel in the tanks has unusable as well.
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Add the unusable fuel to obtain the total fuel required in the tanks.
Note, the unusable fuel differs throughout the series, consult your POH for the
correct figure, and convert as required to litres in this case.
•
The fuel in the tanks should be checked against that required. If more, the
actual dipped fuel must be used, or the aircraft de-fuelled. If less the aircraft
must be fuelled to the minimum required, or to the maximum permitted by the
weight and balance. The actual fuel in the tanks (“dipped fuel”) is then entered
in the fuel planning worksheet.
The unusable fuel is already in the empty weight, so we must again subtract the
unusable fuel from the dipped fuel, to calculate the mass of the fuel for the
mass and balance calculation.
To use fuel quantity in the mass and balance calculation, we need to convert fuel
volume into weight. Using the formula in the table, we will find 113 litres usable
fuel is equivalent to 180 pounds of usable fuel (unusable fuel is allowed for in
the aircraft empty weight).
Fuel Planning Worksheet
Date:
01/ 01/ 2000
Reg. V5-ATN
Cessna 172
FLIGHT TIME @ 30 LITRES* / HOUR
10 % CONTINGENCY FUEL
RESERVE (45 MINS) @ 30 LITRES* / HOUR
ALTERNATE FUEL (as applicable)
ADDITIONAL FUEL (PIC's required conditions fuel)
MINIMUM TAKEOFF FUEL
TAXI (8lbs)
12lt
5
23
10
83
5
MIN RAMP FUEL
88
UNUSABLE FUEL
11
MIN DIPPED FUEL
Extra
LITRES
45
TOTAL FUEL DIPPED
LESS UNUSABLE FUEL
(Included in aircraft empty weight)
LITRES TO POUNDS
TOTAL FUEL LOAD
At SG 0.72
TOTAL FUEL WEIGHT TO WEIGHT AND BALANCE
by O. Roud & D. Bruckert © 2006, This Edition 2014
99lt
124lt
-11
113lt
x 1.584
180lbs
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Fuel Planning Considerations
When filling in the fuel figure, always round up, and never use units smaller
than a litre, or a quarter gallon.
The BLOCK fuel figure of 30 litres an hour provides a safe margin for
contingency for most models, the 180hp models will require a block of 35 litres.
Early models of C172 with smaller engines will burn less. The block figure allows
for takeoff and climb. On shorter flights it is sometimes easier and more
accurate to use a block figure, typically around 20% higher than the POH leaned
cruise figures.
On longer flights, when the aircraft is properly leaned at altitude, fuel
consumption in the cruise will be much lower, and POH fuel figures may be
consulted, along with the climb graph for climb fuel. When using climb and
descent profiles, remember to use the temperature and winds at two thirds of
the change in altitude for climb, and half the change in altitude for descent.
The 10% CONTINGENCY, where not legally required is absolutely essential for
good airmanship. If the aircraft you are flying has a fuel monitoring program,
fuel consumption will be known more accurately. Generally, where this is not in
place, the figures in the POH are optimistic and there can be a wide variation in
fuel burn in piston engine aircraft.
If ALTERNATE FUEL is required the same calculations for trip fuel are required.
Even if not legally required, it's a good airmanship to have an alternate airport,
especially if there is only one runway at your destination.
ADDITIONAL FUEL is fuel that is required by the PIC for expected circumstances
which will result in additional flight time, for example ATC routing, traffic,
weather. Additional fuel is legally required in most countries, if it is not legally
required, again it is good airmanship to carry it.
TAXI FUEL is always applied as the difference between maximum ramp weight
and maximum takeoff weight. Where no ramp weight is available taxi fuel is
best included in the trip fuel calculations.
Weight and Balance
The maximum takeoff and landing weight is 2300 pounds (1045kg) on most
models of C172. The unladen weight is approximately 1400 lbs (636 kg) and
includes full oil and usable fuel.
The actual weight of the aircraft you are flying should always be used for weight
and balance calculations. Refer to the relevant weight and balance certificate
(which should be not older then 5 years) carried on board the aircraft for exact
weight for each aircraft.
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
It is the pilot in command's responsibility to ensure that the aircraft is
properly loaded and within limits prior to departure. It is vital for safety and
performance considerations to know your operating weight and centre of gravity
condition in flight.
Aeroplane balance is maintained by controlling the position of the Centre of
Gravity. Overloading, or mis-loading, may not result in obvious structural
damage, but can cause fatigue on internal structural components or produce
hazardous aeroplane handling characteristics.
An overweight aircraft will have increased takeoff distance, climb rates, cruise
speeds and landing distance.
An aeroplane loaded past the rear limit of its permissible Centre of Gravity range
will have an increased tendency for over-rotation, loss of elevator control on
landing and, although a lower stall speed, a more unstable stall spin tendency.
Aircraft loaded past the forward limit will result in a higher stall speed, and
wheel-barrowing on takeoff or landing.
If spinning or other approved semi-aerobatic maneouvres are planned, the mass
and balance must be inside the Utility Category limits.
Weight and Balance Calculations
Once the weight of the minimum fuel required is known, the weight and balance
requirements may be calculated.
Begin with entering the Aircraft Empty Weight. This may be obtained from the
aircraft flight manual or documents folder and is different for every aeroplane.
In the example we used the Basic Empty Weight 1400 and Centre of Gravity of
39 inches, giving a moment of 54600inch-pounds.
Enter the actual weights or standard weights for the crew and passenger. If
weights are not known standard weights must be used for all occupants. Then
enter the fuel and baggage.
Add all the figures together to obtain the total takeoff weight. This must be less
than the maximum allowable take off weight, 2300lbs, in our example for a
standard C172N. Should it be higher, weight must be removed until it is below
the maximum. Baggage or passengers may be offloaded, or a shorter flight
planned with a lower fuel requirement.
Moments may then be calculated by multiplying the weight (mass in lbs) by the
moment arm (inches from the datum), to obtain the moment in lbs/inches.
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Weight & Balance Worksheet
ITEM
WEIGHT
Aircraft Empty Weight
(From in-flight documents)
1
ARM
MOMENT / 1000
4
0
0
39
5 4 6 0 0 .
0 0
Pilot
1
5
0
37
5 5 5 0 .
0 0
Passenger FRONT SEAT
1
8
0
37
6 6 6 0 .
0 0
REAR SEAT PASSENGERS
3
4
0
73
2 4 8 2 0 .
0 0
4
0
95
3 8 0 0 .
0 0
0
123
.
0 0
47.9
8 6 2 2 .
0 0
45.55 1 0 2 9 4 2 .
0 0
Baggage Area 1
(Max 120lbs)
Baggage Area 2
(Max 50lbs)
Fuel Weight
1
8
0
2
6
0
4
0
0
0
7
0
3
0
(Max 240lbs)
Takeoff Weight
2
(Max 2300lbs)
Adjustment ( Fuel
Takeoff Weight
)
2
3
47.9
1 9 2 6 .
0 0
45.59 1 0 4 8 6 8 .
0 0
(Max 2300lbs)
Less Fuel Burn
Landing Weight
2
2
47.9
3 4 2 0 .
0 0
45.52 1 0 1 4 4 8 .
0 0
(Max 2300lbs)
Weight x Arm = Moment; Final C of G = Total moments / Total weights
NOTE: All weights and arms used in weight and balance calculation should be in
the same units. Moments are divided by 1000 for more easily workable
numbers, and this is also the format used in the Pilot's Operating Handbook.
The centre of gravity (C of G) of the aeroplane in its takeoff condition can be
determined by dividing Takeoff Moment by Takeoff Weight. In our case the
centre of gravity for takeoff will be 45.59 inches for takeoff.
To determine that the C of G is within the approved envelope, enter takeoff
weight and moment (or C of G depending on the graph) in Centre of Gravity
Limits graph from the POH. Use a ruler to confirm the position as shown in the
example below. If Centre of Gravity is located outside the envelope, the
baggage should be shifted or removed and the Weight and Balance must be
computed again to insure the aircraft centre of gravity located within the limit.
Once the aircraft is loaded within limits for takeoff, the landing condition may
then be determined in similar manner with a C of G of 45.52 inches aft of the
datum.
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Note, it sometimes may be necessary to calculate how far we can fly with the
load on board then plan fuel stops in the required distance, in this case the
calculation must be reversed. In this example we had 180lbs of fuel on board,
but we were 40lbs below maximum weight. If the airfield we are operating is
more than adequate for takeoff and landing performance (see below), we can
add additional fuel to the maximum allowable, allowing extra 'thinking time', in
case of a diversion or unexpected situation.
When performing spins the aircraft must be within the utility category centre of
gravity limits.
Performance Planning
Once we know what the actual weight will be for takeoff and landing, the takeoff
and landing performance can be checked to ensure the field length is adequate.
For this the tables TAKEOFF DISTANCE and LANDING DISTANCE from the
performance section of the C172 POH must be used.
For demonstration of the process we've included sample graphs from a C172
POH, and worksheets for assisting in the calculations. The takeoff and landing
graphs and worksheets referred to in the example can be seen on the pages
following. Blank copies of the worksheets are included at the end of the book,
and may also be obtained from http://www.redskyventures.org as a free
download.
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With takeoff and landing calculations, normally no wind is considered, as an into
wind runway should normally be chosen, increasing the performance and
providing a safety factor over the distance calculated. If you are operating into a
one-way airfield, any prevailing tailwind must be considered, up to the limit of
10kts.
The pressure altitude was calculated using the standard formulas provided in the
front of this manual. Performance graphs vary between different manuals, and
some may also require calculation of density altitude, confirm that the altitude
and temperature have been applied correctly, as density and pressure altitude
can be significantly different, as shown in the example below.
Runway Factors (UKCAA recommendations)
CONDITION
Takeoff Distance Factor
Landing Distance Factor
(increase in distance from initiating the (increase in distance from 50ft t the end of
takeoff roll up to a height of 50ft)
the landing roll)
Dry Grass* up to 20cm/8in
(on firm soil)
1.2
20%*
1.1
10%+
Wet Grass* up to 20cm/8in
(on firm soil)
1.1
10%*
1.3
30% **
1.25
25%**
1.25
25%+
Soft Ground or Snow ** +
Rules of Thumb
To be used when it is impractical to refer to the flight
manual, for example in a time critical diversion
An increase of 10% in weight
1.2
20%
1.1
10%
An increase of 10
ambient temperature
1.1
10%
1.05
5%
A 2% slope*
1.1
10%*
1.1
10%*
A tailwind component of 10%
of lift off speed
1.2
20%
1.2
20%
An increase in 1000ft of field
elevation
1.1
10%
1.05
5%
Additional safety factor
1.33
33%
1.43
43%
deg
Factors used together MUST be multiplied, e.g. wet grass with a 2% slope : 1.1x1.1=1.21
Any deviation from normal operating techniques will result in a decrease in performance
* Effect on ground roll will be greater
+ Dry grass and soft fields may reduce ground roll, but it is safer to apply a factor until the
performance is established without doubt
** In theses cases, depending on the surface condition, the factor may be more, as high as
60% increase in ground roll, particularly for rough fields and for hard surfaced short wet
grass.
The surface conditions provided for in performance tables by Cessna, in most
POHs do not cover all the wonderful ways we put our Cessna aircraft to use
today, but nor does it preclude them, as where there is a specific operating
limitation, it must be stated. The table on the above, from the UKCAA LASORS,
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is a recommendation for application of performance degradation factors when no
factor is specified by the manufacturer.
Remember all figures should be rounded up for an additional built in safety
margin and make sure that all factors, such as runway slope and surface have
been considered and applied correctly in the distances calculation.
If the manual provides a figure, this figure or a higher figure must be used. For
example in the sample landing distance tables on the following pages, the factor
for dry grass from the POH is 45% of the ground roll. The table provided here
gives a figure of 1.20% of the total distance. The increase for 45% of ground
roll is 257ft, whereas the increase using a factor of 1.2 x the total distance 1335
= 267ft, so this higher figure can be used instead.
Departure Performance Example
DEPARTURE AIRFIELD: FYWE, Eros
DATE: 01-Jan-2000
PIC: A Safepilot
AIRCRAFT: C172N
REG: V5.ATN
NOTE: ALL Calculations require correct integer (+ or – sign) to be carried through
(1) Pressure altitude (PA) = Altitude AMSL + 30 x (1013-QNH)
Standard QNH
Minus Airfield Equals (+/-)
QNH
ft per mb
Equals (+/-)
+ELEVATION
PRESSURE ALTITUDE
5810ft
1013
-1005 8
x30
240
5570
(2) Standard Temperature ST=15–2xPA/1000 ie. 2 degrees cooler per 1000ft altitude
(Use only if not allowed for on Graphs)
Pressure ALT
Divide by
1000
Equals
5810
/1000 5.81
Multiply by (-2)
Equals (-)
Add 15
x-2
-11.62
15
STANDARD TEMP
+3.38 ≅ 3 deg C
(3) Density altitude (DA)DA = PA +(-) 120ft/deg above (below) ST
(Use only if not allowed for on Graphs)
+ACTUAL TEMP
STD TEMP
Equals (+/-)
Multiplied by ft per
degree
30
3
27
x120
Wind Mag
Runway
Heading
Magnetic
Difference
10
X-60
H-30
Wind degrees True Deviation
+W/-E
295
+/-14 310
Equals
+Press Alt
DENSITY ALTITUDE
3240
5810 9050
Multiply by Closest Wind in
Approx. HWC/XWC
Factor
Knots
30=x0.5 15
XWC =13.5
45=x0.7
HWC =7.5 x 0.5 ≅ 3 kts
60=x0.9
T-full
TWC - nil
T = full
Surface Dry/Wet/Paved/Grass/Gravel/Other______
Slope: Nil Sig.
TAKE OFF ROLL REQUIRED1585
FACTORS FOR GROUND ROLL________
BASIC TAKEOFF DISTANCE2895
FACTORS: WIND____ SLOPE____ SURFACE___ TOTAL FACTOR 1.33
SAFETY_1.33__ OTHER________________
TOTAL RUNWAY LENGTH REQUIRED
3850ft
TAKEOFF DISTANCE AVAILABLE
6000ft
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Rounding up when runway length permits can also be done to alleviate some of
the arduous calculations. When the temperature is below standard, or the QNH
above standard, the density and pressure altitude are below actual. In this case
distances will be lower, and therefore the actual elevation can may be used,
saving time in calculations and adding a small safety margin.
When reviewing the runway distance available, ensure length is considered in
the correct units, if needed convert from feet to meters. In many cases a
conversion factor must be applied. Always check your answers by reasoning, for
example as a quick cross check of unit conversions figures in pound are at least
double kilograms, and feet three times metres.
It is good practice to apply an additional safety margin to calculated distances
for actual aircraft and pilot performance, however the runway length available
should be at least equal to or greater than the takeoff or landing distance
required, whichever is higher. The UKCAA recommend applying the safety factor
above, the runway should be 1.33 time greater for takeoff and 1.43 for landing
than that required, in all situations to allow for differences from manufacturers
figures (obtained with a new aeroplane), variations in the effects of surface and
wind, and to compensate for pilot performance.
SAMPLE – NOT FOR OPERATIONAL USE
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Arrival Performance Example
ARRIVAL AIRFIELD: FYGB, Gobabis
DATE: 01-Jan-2000
PIC: A Safepilot
AIRCRAFT: C172N
REG: V5.ATN
NOTE: ALL Calculations require correct integer (+ or – sign) to be carried through
(1) Pressure altitude (PA) = Altitude AMSL + 30 x (1013-QNH)
Standard QNH
Minus Airfield Equals (+/-)
QNH
ft per mb
Equals (+/-)
+ELEVATION
PRESSURE ALTITUDE
4520
1013
-1020 -7
x30
-210
4730
(2) Standard Temperature ST=15–2xPA/1000 ie. 2 degrees cooler per 1000ft altitude
(Use only if not allowed for on Graphs)
Pressure ALT
Divide by
1000
Equals
4520
/1000 4.52
Multiply by Negative Two Equals (-)
(-2)
Add 15
x-2
15
-9.04
STANDARD TEMP
+4.96 ≅ 5
(3) Density altitude (DA)DA = PA +(-) 120ft/deg above (below) ST
(Use only if not allowed for on Graphs)
ACTUAL TEMP
-STD TEMP
Equals (+/-)
Multiplied by ft per
degree
Equals
-3
5
-8
x120
-720
+Press Alt
DENSITY ALTITUDE
4520 3800ft
(4) Estimated HWC/XWC (Use only if strong winds)
Wind degrees True Deviation
+W/-E
325
Wind Mag
+15W 340
Runway
Heading
Magnetic
Difference
Multiply by Closest Wind in
Factor
Knots
Approx. HWC/XWC
290
X-40
30=x0.5 10
45=x0.7
60=x0.9
XWC – x0.7 ≅ 7 kts
H-50
Surface
HWC – x 0.7 ≅ 7 kts
T-full
TWC – 10 (full)
Dry/Wet/Paved/Grass/Gravel/Other______
Slope: 2%DN
LANDING GROUND ROLL REQUIRED 570
FACTORS FOR GROUND ROLL___0.45_____257
TOTAL LANDING DISTANCE REQUIRED1335+257 = 1592
FACTORS: WIND_1.5_ SLOPE_1.1__ SURFACE____ TOTAL FACTOR 2.36
SAFETY_1.43__ OTHER___________________
TOTAL RUNWAY LENGTH REQUIRED
3757 ≅ 3800ft
LANDING DISTANCE AVAILABLE 1600mx3.28=5248ft
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SAMPLE – NOT FOR OPERATIONAL USE
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REVIEW QUESTIONS
1) If the
a)
b)
c)
magneto selector is turned to OFF:
there will be a drop in engine rpm
the rpm will stay the same
the engine will stop
2) Two complete separate ignition systems provide:
a)
more safety only
b)
more efficient burning only
c)
more safety and more efficient burning
d)
dual position key switching
3) Switching the ignition OFF connects the magneto system to ground:
a)
true
b)
false
4) If a magneto ground wire comes loose in flight, the engine:
a)
will stop
b)
will continue running with lower rpm
c)
will continue running
5) The spark plugs are provided with electrical supply from:
a)
battery at all times
b)
the magnetos
c)
the battery at start-up and then the magnetos
6) The most probable reason an engine continues to run after ignition switch has
been turned off is:
a)
carbon deposit glowing on the spark plugs;
b)
a magneto ground wire is in contact with the engine casing;
c)
a broken magneto ground wire.
7) Cessna 172 engine has:
a)
fuel injection system;
b)
carburettor located on the bottom of the engine;
c)
carburettor located on the top of the engine.
8) Cessna 172 engines are:
a)
sensitive to carburettor ice;
b)
not affected by carburettor ice;
c)
it depends on the model;
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9) Carb
a)
b)
c)
Heat is used to:
prevent carburettor ice;
provide better fuel mixing in the carburettor as it evaporates quickly;
to heat the air/fuel mixture, to improve burning in the engine.
10) The
a)
b)
c)
pilot controls the fuel/air ratio with the:
throttle;
carb. heat;
mixture.
11) For
a)
b)
c)
takeoff at a sea level airport, the mixture control should be:
in the leaned position for maximum rpm;
in the full rich position;
the engine is not affected by mixture setting below 3000ft.
12) What will occur if the mixture control remains full rich, as the flight altitude
increases:
a)
the volume of air entering the carburettor decreases and the amount of
fuel decreases, resulting in a rich mixture;
b)
the density of air entering the carburettor decreases and the amount of
fuel increases, resulting in a rich mixture;
c)
the density of air entering the carburettor decreases and the amount of
fuel remains constant, resulting in a rich mixture.
13) The correct procedure to achieve the best fuel/air mixture when cruising at
altitude is:
a)
to move the mixture control toward LEAN until engine rpm starts to
drop;
b)
to move the mixture control toward LEAN until engine rpm reaches a
peak value;
c)
to move the mixture control toward RICH until engine rpm starts to
drop;
d)
to move the mixture control toward LEAN until engine rpm reaches a
peak EGT and then toward RICH to get EGT 50-100 degrees below the
peak.
14) Extra fuel in a rich mixture causes:
a)
engine heating;
b)
engine cooling;
c)
does not affect the heating or cooling of the engine.
15) If after the mixture is properly adjusted while cruising at the altitude and
pilot forgets to enrich the mixture during descent:
a)
the engine may cut-out due to too rich mixture;
b)
the engine may cut-out due to too lean mixture;
c)
a too rich mixture will create high cylinder head temperatures;
d)
a to lean mixture will create high cylinder head temperatures.
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16) The
a)
b)
c)
d)
remedy for suspected carburettor ice is to:
en-richen the mixture;
lean the mixture;
apply carb heat;
increase power by advancing the throttle.
17) If carb heat is applied:
a)
rpm will increase due to the leaner mixture;
b)
rpm will decrease due to the leaner mixture;
c)
rpm will decrease due to the richer mixture.
18) When the engine is primed for start-up, the fuel priming pump delivers fuel:
a)
through the carburettor to the induction manifold;
b)
through the carburettor to each cylinder;
c)
directly to the cylinders bypassing the carburettor.
19) Water tends to collect at the:
a)
lowest point in the fuel system;
b)
highest point in the fuel system.
20) The engine oil system is provided to:
a)
reduce friction between moving parts and ensure high engine
temperatures;
b)
reduce friction between moving parts and prevent high engine
temperatures;
c)
increase friction between moving parts and prevent high engine
temperatures.
21) Oil grades:
a)
should not be mixed;
b)
may be mixed.
22) With too little oil, you may observe:
a)
high oil temperature and high oil pressure;
b)
high oil temperature and low oil pressure;
c)
low oil temperature and low oil pressure.
23) What action can a pilot take to aid in cooling an engine that is overheating
during a climb:
a)
lean the mixture and increase airspeed;
b)
en-richen the mixture and increase airspeed;
c)
increase airspeed and reduce engine rpm.
24) Normal in-flight electrical power is provided by an:
a)
alternator;
b)
battery;
c)
generator.
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25) A distribution point for electrical power to various services is:
a)
circuit breaker;
b)
distributor;
c)
bus bar.
26) The battery master switch should be turned to OFF after the engine is
stopped to avoid the battery discharging through:
a)
the magnetos;
b)
the generator;
c)
electrical services connected to it.
27) The suction (or vacuum gauge) shows the pressure:
a)
below atmospheric pressure;
b)
above atmospheric pressure.
28) The
a)
b)
c)
vacuum pump is:
electrically-driven;
engine-driven;
hydraulically-driven.
29) The
a)
b)
c)
following instrument will be affected by a vacuum pump failure:
artificial horizon and the direction indicator;
turn and bank indicator;
airspeed indicator.
30) The
a)
b)
c)
aircraft is equipped with:
a fixed pitch propeller;
a variable pitch propeller;
may have a fixed pitch or variable pitch propeller depending on model.
31) The pilot should shut-down an engine after start if the oil pressure does not
rise within:
a)
30 seconds;
b)
1 minutes;
c)
10 seconds.
32 Engine power is monitored by the:
a)
manifold pressure gauge;
b)
engine rpm gauge.
33) The usual method of shutting an engine down is to:
a)
switch the magnetos off;
b)
move the mixture to idle cut-off;
c)
switch the master switch off.
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34) Fuel
a)
b)
c)
tanks is are located:
in the aft cabin;
beneath the pilot seats;
in the wings.
35) The
a)
b)
c)
aircraft is equipped with:
electrically operated elevator trim tab;
manually-operated elevator trim;
manually-operated elevator and rudder trim;
36) Frise type ailerons are used to:
a)
reduce airflow over the control surface to make the control lighter;
b)
reduce the adverse aileron yaw during bank;
c)
this aircraft does not have Frise type of ailerons;
37) The
a)
b)
c)
flaps are:
hydraulically-operated;
electrically-operated;
manually-operated;
38) Fill in the following from the aircraft you are flying:
Aircraft model _________, year______;
a) The best glide speed at maximum weight is _____________.
b) The best rate of climb speed at sea level is_______, at 10'000ft_______.
c) The recommended normal climb speed at sea level is___________.
d) The recommended takeoff speed at sea level, and maximum weight for a
short field is___________, for a normal landing is________________.
e) The recommended landing speed at sea level and maximum weight for a
short field is___________, for a normal landing is________________.
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CESSNA 172 TRAINING MANUAL
NAVIGATION AND PERFORMANCE WORKSHEETS
Navigation Calculation Work Sheet
Date:
FM
TO
/
/
FL
REG:
Temp
W/V IAS
PIC:
TAS
DRIF Hdg
T
T
VAR.
Hdg
M
G/S
Dist
EET
TOTALS
Fuel Planning Worksheet
LITRES
ENROUTE TIME @ ______ LITRES / HOUR
10 % CONTINGENCY FUEL
RESERVE (45 MINS) @ ______ LITRES / HOUR
____ litres
TAXI / TAKEOFF
UNUSABLE FUEL
MIN FUEL REQUIRED
TOTAL FUEL DIPPED
LESS UNUSABLE FUEL (Included in aircraft empty weight)
LITRES TO POUNDS (AVGAS 100LL)
x 1.584
TOTAL FUEL WEIGHT (TO WEIGHT AND BALANCE
SHEET)
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CESSNA 172 TRAINING MANUAL
WEIGHT AND BALANCE WORKSHEET
ITEM
WEIGHT
ARM
MOMENT / 1000
Aircraft Empty Weight (Flt.
Man/DOCUMENTS FOLDER)
Pilot
Passenger FRONT SEAT
REAR SEAT PASSENGERS
Baggage Area 1
(Max ______lbs)
Baggage Area 2
(Max ______lbs)
Fuel Weight
(Max ______lbs)
Takeoff Weight
(Max _______lbs)
Adjustment
Takeoff Weight
(Max _______lbs)
Less Fuel Burn
Landing Weight
(Max _______lbs)
Weight x Arm = Moment.
Total Moment = Sum of all Moments (+ or -)
Total Weight = Sum of all Weights (+ or -)
Final C. of G. = Total moment / Total weight
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CESSNA 172 TRAINING MANUAL
DEPARTURE AND ARRIVAL PERFORMANCE: DEPARTURE AIRFIELD
DEPARTURE AIRFIELD:
DATE:
(dd-mmm-yy)
PIC:
AIRCRAFT:
REG:
NOTE: ALL Calculations require correct integer (+ or – sign) to be carried through
(1) Pressure altitude (PA) = Altitude AMSL + 30 x (1013-QNH)
Standard QNH
Minus Airfield Equals (+/-)
QNH
ft per mb
Equals (+/-)
+ELEVATION
PRESSURE ALTITUDE
1013
x30
(2) Standard Temperature ST=15–2xPA/1000 ie. 2 degrees Celsius cooler per 1000ft
altitude (Use only if not allowed for on Graphs)
Pressure ALT
Divide by
1000
Equals
/1000
Multiply by (-2) deg per Equals (-)
deg Celsius
Add 15
x-2
+15C
STANDARD TEMP
(3) Density altitude (DA)DA = PA +(-) 120ft/deg above (below) ST
(Use only if not allowed for on Graphs)
+/-ACTUAL TEMP
minus +/STD TEMP
Equals (+/-)
Multiplied by ft per
degree
Equals (+/-)
+Press Alt
DENSITY ALTITUDE
Magnetic
Difference
Multiply by
Closest Factor
Wind in Knots
Approx. HWC/XWC
XHT-full
30=x0.5
45=x0.7
60=x0.9
x120
Wind degrees True Deviation
+W/-E
Wind Mag
Runway
Heading
T = 1.0
XWCHWCTWC -
x0.5
Surface
Dry/Wet/Paved/Grass/Gravel/Other______
Slope:
UP
TAKE OFF ROLL REQUIRED
FACTORS FOR GROUND ROLL________
BASIC TAKEOFF DISTANCE
FACTORS: WIND____ SLOPE____ SURFACE___ TOTAL FACTOR ______
SAFETY_1.33__ OTHER________________
TOTAL RUNWAY LENGTH REQUIRED
TAKEOFF DISTANCE AVAILABLE
by O. Roud & D. Bruckert © 2006, This Edition 2014
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CESSNA 172 TRAINING MANUAL
DEPARTURE AND ARRIVAL PERFORMANCE: ARRIVAL AIRFIELD
ARRIVAL AIRFIELD:
DATE:
(dd-mmm-yy)
PIC:
AIRCRAFT:
REG:
NOTE: ALL Calculations require correct integer (+ or – sign) to be carried through
(1) Pressure altitude (PA) = Altitude AMSL + 30 x (1013-QNH)
Standard QNH
Minus Airfield Equals (+/-)
QNH
ft per mb
Equals (+/-)
+ELEVATION
PRESSURE ALTITUDE
1013
x30
(2) Standard Temperature ST=15–2xPA/1000 ie. 2 degrees Celsius cooler per 1000ft
altitude (Use only if not allowed for on Graphs)
Pressure ALT
Divide by
1000
Equals
/1000
Multiply by (-2) deg per Equals (-)
deg Celsius
Add 15
x-2
+15C
STANDARD TEMP
(3) Density altitude (DA)DA = PA +(-) 120ft/deg above (below) ST
(Use only if not allowed for on Graphs)
+/-ACTUAL TEMP
minus +/STD TEMP
Equals (+/-)
Multiplied by ft per
degree
Equals (+/-)
+Press Alt
DENSITY ALTITUDE
x120
Wind degrees True Deviation
+W/-E
Surface
Wind Mag
Runway
Heading
Magnetic
Difference
Multiply by
Wind in Knots
Closest Factor
XHT-full
30=x0.5
45=x0.7
60=x0.9
T = 1.0
Dry/Wet/Paved/Grass/Gravel/Other______
LANDING GROUND ROLL REQUIRED
Approx. HWC/XWC
XWCHWCx0.5
TWC –
(full)
Slope:
DN
FACTORS FOR GROUND ROLL___0.45_____
TOTAL LANDING DISTANCE REQUIRED
FACTORS: WIND_ _ SLOPE_ __ SURFACE____ TOTAL FACTOR _______
SAFETY_1.43__ OTHER_________
__________
TOTAL RUNWAY LENGTH REQUIRED
LANDING DISTANCE AVAILABLE
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IN-FLIGHT LOG
FM
TO
Alt/FL
TRK
True
W/V
HDG
True
HDG Dist
Mag
G/S
EET
ETA1 ETA2
ETA3
ATA
TOTALS
FUEL LOG
LEFT TANK
TIME ON
RIGHT TANK
FUEL USED
REMAINING
TIME ON
FUEL USED
REMAINING
CLEARANCES/ATIS
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
____________________________
by O. Roud & D. Bruckert © 2006, This Edition 2014
Page 177