Warm-Up – 4/2 – 10 minutes
Utilizing your notes and past knowledge answer the
following questions:
1)
2)
3)
4)
5)
Describe the purpose of the VSI.
Describe the differential pressure used within the
VSI.
Describe the two types of information the VSI
provides.
What happens to the VSI when the pilot pulls back
on the yoke/stick?
What is the time period from the initial change in the
rate of climb to the indication of the new rate
indicated on the VSI?
Questions / Comments
Warm-Up – 4/2 – 10 minutes
Utilizing your notes and past knowledge answer the
following questions:
1)
2)
3)
4)
5)
Describe the purpose of the VSI.
Describe the differential pressure used within the
VSI.
Describe the two types of information the VSI
provides.
What happens to the VSI when the pilot pulls back
on the yoke/stick?
What is the time period from the initial change in the
rate of climb to the indication of the new rate
indicated on the VSI?
Vertical Speed Indicator (VSI)
• The VSI indicates whether
the aircraft is climbing,
descending, or in level
flight.
• The rate of climb or
descent is indicated in feet
per minute (fpm).
• If properly calibrated, the
VSI indicates zero in level
flight.
Warm-Up – 4/2 – 10 minutes
Utilizing your notes and past knowledge answer the
following questions:
1)
2)
3)
4)
5)
Describe the purpose of the VSI.
Describe the differential pressure used within the
VSI.
Describe the two types of information the VSI
provides.
What happens to the VSI when the pilot pulls back
on the yoke/stick?
What is the time period from the initial change in the
rate of climb to the indication of the new rate
indicated on the VSI?
Principle of Operation
• This causes a pressure
differential that is
indicated on the
instrument needle as a
climb or descent.
Warm-Up – 4/2 – 10 minutes
Utilizing your notes and past knowledge answer the
following questions:
1)
2)
3)
4)
5)
Describe the purpose of the VSI.
Describe the differential pressure used within the
VSI.
Describe the two types of information the VSI
provides.
What happens to the VSI when the pilot pulls back
on the yoke/stick?
What is the time period from the initial change in the
rate of climb to the indication of the new rate
indicated on the VSI?
Principle of Operation
• The VSI displays two
different types of
information:
• • Trend information shows
an immediate indication of
an increase or decrease in
the aircraft’s rate of climb
or descent.
• • Rate information shows a
stabilized rate of change in
altitude.
Warm-Up – 4/2 – 10 minutes
Utilizing your notes and past knowledge answer the
following questions:
1)
2)
3)
4)
5)
Describe the purpose of the VSI.
Describe the differential pressure used within the
VSI.
Describe the two types of information the VSI
provides.
What happens to the VSI when the pilot pulls back
on the yoke/stick?
What is the time period from the initial change in the
rate of climb to the indication of the new rate
indicated on the VSI?
Principle of Operation
• If an aircraft is maintaining
level flight and the pilot
pulls back on the control
yoke causing the nose of
the aircraft to pitch up, the
VSI needle moves upward
to indicate a climb.
Warm-Up – 4/2 – 10 minutes
Utilizing your notes and past knowledge answer the
following questions:
1)
2)
3)
4)
5)
Describe the purpose of the VSI.
Describe the differential pressure used within the
VSI.
Describe the two types of information the VSI
provides.
What happens to the VSI when the pilot pulls back
on the yoke/stick?
What is the time period from the initial change in the
rate of climb to the indication of the new rate
indicated on the VSI?
Principle of Operation
• If the pitch attitude is held
constant, the needle
stabilizes after a short
period (6–9 seconds) and
indicates the rate of climb
in hundreds of fpm.
• The time period from the
initial change in the rate of
climb, until the VSI displays
an accurate indication of
the new rate, is called the
lag.
Questions / Comments
THIS DAY IN AVIATION

April 2
• 1794 — The world's first air
force, the Aerostatic Corps
of the Artillery Service is
formed in France following a
demonstration ascent from
the gardens of the ChalaisMeudon on the outskirts of
Paris in the hydrogen
balloon L'Entreprenant, the
first used for military tests.
THIS DAY IN AVIATION

April 2
• 1937 — Swedish airplane
manufacturer Svenska
Aeroplan Aktiebolaget
(SAAB) is established in
Trollhättan, Sweden.
THIS DAY IN AVIATION

April 2
• 1951 — Establishment of
the USAF Air Research
and Development
Command announced.
THIS DAY IN AVIATION

April 2
• 1997 — A Boeing 777,
powered by twin RollsRoyce Trent 892 turbofans,
returns to Seattle to set a
new Eastbound speed
around the world record of
553 mph.
• En route, the twinjet sets a
Great Circle distance
without landing record of
12,455.34 miles when flying
from Seattle to Kuala
Lumpur, Malaysia.
Questions / Comments
March/April 2014
SUNDAY
30
MONDAY
31
TUESDAY
1
WEDNESDAY
2
Chapter 7
Chapter 7
Gyro Systems
Magnetic
Compass
THURSDAY
3
FRIDAY
4
SATURDAY
5
FltLine Friday
6
7
8
9
10
11
12
13
14
15
16
17
18
19
SPRING BREAK
SPRING BREAK
SPRING BREAK
SPRING BREAK
SPRING BREAK
21
22
23
24
25
20
FltLine Friday
27
28
29
30
26
Questions / Comments
Chapter 7 – Flight Instruments
FAA – Pilot’s Handbook of Aeronautical Knowledge
Today’s Mission Requirements
 Mission:

Identify in writing how to interpret and operate flight instruments.

Describe the pilot’s ability to recognize errors and malfunctions
with flight instruments.

Describe the pitot-static system and associated instruments.

Describe the vacuum system and related instruments.

Describe the gyroscopic instruments and the magnetic compass.

EQ:
Describe the importance of Aeronautical Knowledge for the
student pilot learning to fly.
Magnetic Compass
• One of the oldest and
simplest instruments for
indicating direction is the
magnetic compass.
• It is also one of the basic
instruments required by
Title 14 of the Code of
Federal Regulations (14
CFR) part 91 for both VFR
and IFR flight.
Magnetic Compass
• An aircraft magnetic
compass is marked with
letters representing the
cardinal directions, north,
east, south, and west, and
a number for each 30°
between these letters.
• The final “0” is omitted
from these directions. For
example, 3 = 30°, 6 = 60°,
and 33 = 330°.
Magnetic Compass
• There are long and
short graduation
marks between the
letters and numbers,
each long mark
representing 10° and
each short mark
representing 5°.
Magnetic Compass
Induced Errors
• The magnetic
compass is the
simplest instrument in
the panel, but it is
subject to a number of
errors that must be
considered.
Magnetic Compass
Induced Errors
• Variation
• true directions
• magnetic directions
• In aerial navigation,
the difference between
true and magnetic
directions is called
variation.
Magnetic Compass
Deviation
• Magnetic fields in an
aircraft caused by
electrical current
flowing in the structure,
in nearby wiring or any
magnetized part of the
structure, conflict with
the Earth’s magnetic
field and cause a
compass error called
deviation.
Magnetic Compass
Oscillation Error
• Oscillation is a
combination of all of the
other errors, and it
results in the compass
card swinging back and
forth around the
heading being flown.
Outside Air Temperature (OAT)
Gauge
• The outside air
temperature (OAT)
gauge is a simple and
effective device
mounted so that the
sensing element is
exposed to the outside
air.
Outside Air Temperature (OAT)
Gauge
• OAT gauges are
calibrated in degrees
°C, °F, or both.
• An accurate air
temperature provides
the pilot with useful
information about
temperature lapse rate
with altitude change.
Questions / Comments
Gyroscopic Flight Instruments
• Several flight instruments
utilize the properties of a
gyroscope for their
operation.
• The most common
instruments containing
gyroscopes are the turn
coordinator, heading
indicator, and the attitude
indicator.
Gyroscopic Flight Instruments
• Precession can also create
some minor errors in some
instruments.
• Instruments may require
corrective realignment
during flight, such as the
heading indicator.
Gyroscopic Flight Instruments
Sources of Power
• Gyros are vacuum,
pressure, or electrically
operated.
• Most aircraft have at least
two sources of power to
ensure at least one source
of bank information is
available if one power
source fails.
Gyroscopic Flight Instruments
Sources of Power
• The vacuum or pressure
system spins the gyro by
drawing a stream of air
against the rotor vanes to
spin the rotor at high
speed, much like the
operation of a waterwheel
or turbine.
Gyroscopic Flight Instruments
Sources of Power
• Pressure required for
instrument operation
varies, but is usually
between 4.5 "Hg and 5.5
"Hg.
• One source of vacuum for
the gyros is a vane-type
engine-driven pump that is
mounted on the accessory
case of the engine.
Gyroscopic Flight Instruments
Sources of Power
• A typical vacuum system
consists of an enginedriven vacuum pump, relief
valve, air filter, gauge, and
tubing necessary to
complete the connections.
Gyroscopic Flight Instruments
Sources of Power
• Air is drawn into the
vacuum system by the
engine-driven vacuum
pump.
• It first goes through a filter,
which prevents foreign
matter from entering the
vacuum or pressure
system.
Gyroscopic Flight Instruments
Sources of Power
• The air then moves
through the attitude and
heading indicators, where
it causes the gyros to spin.
• A relief valve prevents the
vacuum pressure, or
suction, from exceeding
prescribed limits.
Gyroscopic Flight Instruments
Sources of Power
• It is important to monitor
vacuum pressure during
flight, because the attitude
and heading indicators
may not provide reliable
information when suction
pressure is low.
Gyroscopic Flight Instruments
Sources of Power
• When the vacuum pressure
drops below the normal
operating range, the
gyroscopic instruments
may become unstable and
inaccurate.
Turn Indicators
• Aircraft use two types of
turn indicators: turn-andslip indicator and turn
coordinator.
• The turn-and-slip indicator
shows only the rate of turn
in degrees per second.
Turn Indicators
• The turn coordinator can
initially show roll rate and
it indicates rate of turn.
• Both instruments indicate
turn direction and quality
(coordination), and also
serve as a backup source
of bank information in the
event an attitude indicator
fails.
Turn Indicators
• Coordination is
achieved by referring to
the inclinometer, which
consists of a liquidfilled curved tube with
a ball inside.
Turn-and-Slip Indicator
• The gyro in the turnand-slip indicator
rotates in the vertical
plane, corresponding
to the aircraft’s
longitudinal axis.
• The turn-and-slip
indicator uses a
pointer, called the turn
needle, to show the
direction and rate of
turn.
Turn Coordinator
• The gimbal in the turn
coordinator is canted;
therefore, its gyro can
sense both rate of roll
and rate of turn.
• When rolling into or out
of a turn, the miniature
aircraft banks in the
direction the aircraft is
rolled.
Turn Coordinator
• The turn coordinator
can be used to
establish and
maintain a standardrate turn by aligning
the wing of the
miniature aircraft with
the turn index.
Turn Coordinator
• Two marks on each
side (left and right) of
the face of the
instrument.
• The first mark
• a wings level zero
rate of turn.
• The second mark
• indicate a standard
rate of turn.
Turn Coordinator
• A standard-rate turn is
defined as a turn rate of
3° per second.
• The turn coordinator
indicates only the rate
and direction of turn; it
does not display a
specific angle of bank.
Inclinometer
• The inclinometer is
used to depict aircraft
yaw.
• Coordinated flight is
maintained by keeping
the ball centered. If the
ball is not centered, it
can be centered by
using the rudder.
Inclinometer
• To center the ball,
apply rudder pressure
on the side to which
the ball is deflected.
• Use the simple rule,
“step on the ball,” to
remember which
rudder pedal to press.
Inclinometer
Instrument Check
• During the preflight, check to
see that the inclinometer is
full of fluid and has no air
bubbles.
• The ball should also be
resting at its lowest point.
• When taxiing, the turn
coordinator should indicate a
turn in the correct direction
while the ball moves opposite
Attitude Indicator
• The attitude indicator, with its
miniature aircraft and horizon
bar, displays a picture of the
attitude of the aircraft.
• The relationship of the
miniature aircraft to the
horizon bar is the same as the
relationship of the real
aircraft to the actual horizon.
Attitude Indicator
• The instrument gives an
instantaneous indication of
even the smallest changes in
attitude.
• The horizon bar represents
the true horizon.
Attitude Indicator
• The relationship
of the miniature
aircraft to the
horizon bar
should be used
for an indication
of the direction
of bank.
Attitude Indicator
• The attitude
indicator is
reliable and the
most realistic
flight instrument
on the
instrument panel.
Heading Indicator
• The heading indicator is
fundamentally a
mechanical instrument
designed to facilitate the
use of the magnetic
compass.
• Errors in the magnetic
compass are numerous,
making straight flight and
precision turns to
headings difficult to
accomplish, particularly in
turbulent air.
Heading Indicator
• Because of precession
caused by friction, the
heading indicator creeps
or drifts from a heading to
which it is set.
Heading Indicator
• Another error in the
heading indicator is
caused by the fact that the
gyro is oriented in space,
and the Earth rotates in
space at a rate of 15° in 1
hour.
• The heading indicator may
indicate as much as 15°
error per every hour of
operation.
Heading Indicator
Instrument Check
• As the gyro spools up,
make sure there are no
abnormal sounds.
• While taxiing, the
instrument should indicate
turns in the correct
direction, and precession
should not be abnormal.