FOREWORD
Conversations with colleagues, discussions during cruise flight coupled with my
experiences when conducting performance courses in the classroom have led me
to draw the conclusion that aircraft performance is not easily understood by
airline pilots in their daily operation. Aircraft manufacturers and airlines
provide pilots with numerous performance data but it is not always clear when
or how this should be used.
It is because of this that the wish arose for a small guide containing all the
performance rules which might be faced by aircrew both occasionally and on a
daily basis.
This Performance Reference Handbook (PRH) is the result.
This handbook contains European (EASA) performance regulations applicable
to large civil twin-jet aircraft in general and the related data plus application for
the Boeing 737 NG specifically. It is complete with many clarifying pictures and
flowcharts, as we pilots prefer. In addition, due to its handy size it will easily fit
into your flight bag.
Anyway, I hope that this PRH will assist in making performance calculations
and related decisions and help you become more familiar with what specific
performance data represents. Moreover, the computerised era has dawned and
this affects many of us, influencing performance calculations with laptop tools
and EFB. The lack of transparency in computerisation means that many pilots
will lose their overview of this aspect of the operation.
So with respect to the PRH, use, enjoy and don’t hesitate to criticise it, because
I’m looking forward to any remarks, comments and/or feedback!
Maurits Hulshof
Aeronautical Engineer BSc.
CPT/TRI 737NG
Order and update info
You can order your own copy of the PRH from www.performance737.com. The
PRH is available as hard-copy (A5-size, full color or B/W, coilbound) or as ebook. An FAA edition is also available. This site will also inform you about
updates.
Language
In accordance with the Boeing Manuals, this PRH is written in US English.
However, the EU-OPS regulations, which are quoted exactly, are written in UK
English. E.g. you may find the word “airplane” (as text) as well as “aeroplane”
(as quote) in this handbook.
Where the pronoun ‘he’ is used in the PRH, the pronoun ‘she’ could be inferred.
Disclaimer
Although a major part of the contents of this handbook consists of regulatory
data, the PRH is not authorized by any airline, local aviation authority, or by the
manufacturer of the 737NG.
Although this guide has been put together carefully, the author guarantees
neither currency nor accuracy and cannot be held responsible for faults.
Therefore company, manufacturer and state procedures must always take
precedence over this handbook.
Contact
For any remark, comment, feedback or error reporting, please contact:
prh@performance737.com.
Copyright © 2014 M.M.Hulshof
All rights reserved. No part of this publication may be reproduced or transmitted
in any form without the explicit written permission of the author.
Cover
Design and photograph © by the author.
INTRODUCTION
Every public transport aircraft taking off has to meet several minimum
performance requirements in order to be able to reach an acceptable level of
safety throughout the flight from takeoff to the subsequent landing.
These minimum requirements, with respect to aircraft performance, are laid
down in aviation regulations which cover both the aircraft certification and
operation.
Worldwide there are two major aviation rulemaking organizations, EASA and
FAA.
EASA, the European Aviation Safety Agency, established in 2003 and absorbed
the JAA (Joint Aviation Authorities) by 2008, develops, adopts and implements
requirements concerning aircraft design, certification, operation, maintenance
and crew licensing.
Certification requirements for large civil aircraft, as is the Boeing 737NG, are
laid down in Part 25 of EASA’s Certification Specifications (CS-25), replacing
the former JAR-25 (Joint Aviation Requirements), and almost identical to the
FAA (USA’s Federal Aviation Administration) equivalent FAR-25.
Operating requirements are documented in EU-OPS.
This edition of the PRH reflects the EASA aircraft performance regulations
recognized in CS-25 and EU-OPS. Acceptable Means of Compliance (AMC)
and Interpretative / Explanatory Material (IEM) form a part of these regulations
and are also referenced.
(An FAA edition of the PRH is also available on www.performance737.com.)
This handbook contains 4 parts:
Part A: Basic Performance Notes
covers and explains regulatory (EASA) requirements.
Part B: Performance Data 737NG
covers the manufacturer's supplied performance data which are normally
available to pilots, and
explains data adjustments.
Part C: 737NG Performance Data Application
contains a practical as to how the available performance data have to be applied,
both in logical steps and in flowcharts, and
contains additional operational information.
Part D: Appendices
includes snowtam and runway state decoder,
glossary, and
abbreviation list.
LEGEND
Explanations of the icons, dimensions and quotations used in this PRH.
Icons
Action or Check
Additional information
Allowance
Attention
Definition
Equation, Formula or Statement
Restriction
Dimensions
°
degree
"
inch
C
Celsius
F
Fahrenheit
ft
feet
Hg
mercury
g
gravity
hPa
hectoPascal (millibar)
K
1000lbs (Engine thrust rating)
m
meter
mm
millimeter
mph
miles per hour
kts
knots
sec
second
Quotations
CS-25.xxx Quotation of EASA’s Certification Specification Part 25.
AMC-25.xxx Quotation of EASA’s CS Part 25 Acceptable Means of
Compliance.
CS-AWO xxx Quotation of EASA’s CS Part All Weather Operations.
EU-OPS 1.xxx Quotation of EASA’s Operational Requirements.
IEM-OPS 1.xxx Quotation of EU-OPS’s Interpretative Explanatory
Material.
PANS-OPS xxxx Quotation of ICAO’s Procedures for Air Navigation
Services – Aircraft Ops.
CFM Quotation of the manufacturer of the CFM56 engine.
1. TAKEOFF SPEEDS
DEMONSTRATED AND OPERATIONAL SPEEDS
1.1. DEMONSTRATED TAKEOFF SPEEDS
Four speeds are demonstrated during the certification process: the stallspeed
(VS), the minimum unstick speed (VMU) and the minimum control speeds on
the ground (VMCG) and in the air (VMCA).
1.1.1. Stall speed – VS
Stall speed (VS): The minimum steady flight speed at which the airplane is
controllable.
Corresponds to the point where the lift can no longer be sustained.
VS1G is the one-g stall speed corresponding to the maximum liftcoefficient (CL)
where the loadfactor is still equal to 1 (i.e. just before the lift starts decreasing
with increasing angle of attack AOA).
VS1G > VS
The stall speed used in airplane certification is the reference stall speed, VSR.
CS-25.103 The reference stall speed VSR is a calibrated airspeed defined by the applicant.
VSR ≥ VS1G
1.1.2. Minimum Unstick speed – VMU
CS-25.107 VMU is the calibrated airspeed at and above which the aeroplane can safely lif
Demonstrated in flight tests.
Determined at the maximum angle of attack that is physically attainable by the
aircraft while on the ground.
1.1.3. Minimum Control speeds
1.1.3.1. Minimum control speed - Ground – VMCG
CS-25.149VMCG, the minimum control speed on the ground, is the calibrated airspeed du
Crew must be able (without any special skill required) to arrest the lateral
motion caused by an engine failure within 30 feet of the runway centerline, using
only aerodynamic controls (no nosewheel steering).
VMCG is determined with:
the remaining engine at maximum takeoff thrust (bleeds off)
most unfavorable (farthest aft) center of gravity
maximum takeoff weight
airplane trimmed for takeoff
In determining the minimum control speeds the effects of crosswind are not
taken into account.
1.1.3.2. Minimum control speed - Air – VMCA
CS-25.149VMC is the calibrated airspeed, at which, when the critical engine is suddenly m
Maximum 20° heading change during the recovery (without special skill
required) is allowed.
VMCA is determined with:
the remaining engine at maximum takeoff thrust (bleeds off)
most unfavorable (farthest aft) center of gravity
maximum takeoff weight
aircraft trimmed for takeoff
most critical configuration but with gear up
negligible groundeffect
VMCA ≥ 1.2 VS
1.2. OPERATIONAL TAKEOFF SPEEDS
From the demonstrated speeds the following operational speeds are derived:
1.2.1. Takeoff Decision speed - V1
Takeoff Decision speed (V1): The speed used as a reference in the event of
engine or other failure in deciding whether to continue or reject the takeoff.
CS-Definitions V1 means the maximum speed in the take-off at which the pilot must take
Regulations require a single value of V1 for the rejected and continued takeoff.
Regulations account for one second of recognition and reaction time between
VEF, the speed at which the event is assumed to take place, and the pilot’s first
action to reject the takeoff.
CS-25.107VEF is the calibrated airspeed at which the critical engine is assumed to fail. VE
V1 ≥ VEF ≥ VMCG
Minimum V1 is equal to VMCG. This minimum allowable V1 is referred to as:
V1MCG.
Maximum V1 is equal to VMBE and may not exceed VR.
Maximum Brake Energy speed(VMBE): The highest takeoff decision speed
from which the airplane may be brought to a stop without exceeding the
maximum energy absorption capability of the brakes.
VMCG ≤ V1 ≤ VR or VMBE
1.2.2. Rotation speed - VR
AMC-25.111(b)Rotation speed, VR, is intended to be the speed at which the pilot initiates
Chosen such, that given a normal rotation rate of three degrees per second, the
aircraft will achieve V2 at the screenheight at the end of the runway if an engine
fails at VEF.
Results in a safe liftoff speed VLOF.
CS-25.107 VLOF is the calibrated airspeed at which the airplane first becomes airborne.
VR ≥ 1.05 VMCA
VLOF ≥ 1.1 VMU(N) or 1.05 VMU(N-1)
1.2.3. Takeoff Safety speed - V2
CS-DefinitionsTake-off safety speed means a referenced airspeed obtained after liftoff at w
Takeoff Safety speed(V2): The target speed to be reached at the screenheight,
assuming an engine failure at or after V1.
Selected by the certification applicant and is the speed at which the one engine
inoperative second segment climb performance is demonstrated. [PRH A2.3.1.2.
Second segment]
Not necessarily the absolute minimum safety speed for one engine inoperative,
since a higher speed may provide better climb performance and may also be
scheduled to reduce the tail-strike risk on long-body aircraft.
V2 ≥ 1.13 VS1G and 1.1 VMCA
1.2.4. Various influences on operational speeds
V1
Weight
A higher weight requires more lift to be produced. For the conti
Density (OAT/PA)
A lower density (higher OAT or PA) results in less lift force whi
Flap Setting
A higher flapsetting produces more lift which allows a lower V1
Runway Slope
A downslope requires a lower V1 because it hurts the stopping c
Wind
More tailwind requires a lower V1 because it hurts the stopping
OVERVIEW TAKEOFF SPEEDS
2. TAKEOFF PERFORMANCE REQUIREMENTS
MAX ALLOWABLE TAKEOFF WEIGHT
2.1. MAXIMUM ALLOWABLE TAKEOFF
WEIGHT
The maximum weight the aircraft is allowed to takeoff with is limited by:
- legal performance requirements – resulting in a Performance Limit TOW
(PLTOW), which may be further restricted by MEL requirements, and
- a weight taking the airframe structure into account – the Maximum Certified
Structural TOW.
The Max Allowable TOW is determined by the most limiting of the PLTOW and
the Maximum Certified Structural TOW.
The Max Allowable TOW may be further restricted by the Max Allowable LDW
[PRH A3-2. Landing performance requirments - Dispatch] plus the weight of
the tripfuel.
2.1.1. Maximum Certified Structural TOW
Structural weight: The maximum weight the airframe, landing gear and wings
can support.
Specified by the manufacturer but may be lowered by the airline company for
economical reasons (ATC and landingfees are based on this weight).
2.1.2. Performance Limit TOW
Requirements which determine the PLTOW are considering the:
Field Length - to ensure that, following an engine failure at the most critical
moment, the aircraft can either safely continue or reject the takeoff on the
available runway length - resulting in the Field Length Limit TOW. [PRH
A1-2.2. Field length requirement]
Climb - to ensure that the aircraft has sufficient climb capability in all
phases of the takeoff - resulting in the Climb Limit TOW. [PRH A1-2.3.
Climb requirement]
Obstacle Clearance - to ensure that the aircraft is able to clear all obstacles
with the required margin - resulting in the Obstacle Limit TOW. [PRH A12.4. Obstacle clearance requirement]
Tire Speed - to ensure that the maximum speed on the ground prior to
liftoff does not exceed the maximum certified tire speed - resulting in the
Tire Speed Limit TOW. [PRH A1-2.5. Tire speed requirement]
Brake Energy - to ensure that the maximum amount of energy which the
brakes can absorb in the event of a rejected takeoff will not be exceeded resulting, for a given runway, in the Brake Energy Limit TOW. [PRH A12.6. Max brake energy requirement]
Regulations require the PLTOW to be determined taking certain environmental
elements into account.
REQUIRED ENVIRONMENTAL CONDITIONS[EU-OPS 1.490] Not more than 50% of
OVERVIEW MAXIMUM ALLOWABLE TOW
2.2. FIELD LENGTH REQUIREMENT
The maximum takeoff weight with respect to field length is restricted by two
specific requirements which ensure that the aircraft has sufficient performance
for the actual runway available.
Accelerate-Stop Distance Required must not exceed Accelerate-Stop Distance
Available. [PRH A1-2.2.1. Accelerate Stop Distance]
ASDR ≤ ASDA
Takeoff Distance Required must not exceed Takeoff Distance Available. [PRH
A1-2.2.2. Takeoff Distance]
TODR ≤ TODA
The accelerate-stop distance requirement will result in a Accelerate-Stop
Distance (ASD) Limit TOW and the takeoff distance requirement will result in a
Takeoff Distance (TOD) Limit TOW.
The Field Length Limit TOW is the most restrictive (lowest) of the ASD Limit
TOW and the TOD Limit Weight.
In the following definitions and figures TORA is defined as:
EU-OPS 1.480Take-off run available (TORA): The length of runway which is declared av
2.2.1. Accelerate Stop Distance
Aircraft must be able to safely abort the takeoff following an event at VEF.
Accelerate Stop Distance Required (ASDR): The required distance to accelerate
with all (N) engines operating to V1 (including 1 second recognition time
between VEF and V1) plus the required distance to travel 2 seconds at constant
speed V1 (to allow for the transition from acceleration to the stopping
configuration) plus the required distance to decelerate from V1 to a full stop.
In determining the ASDR on a dry runway, no credit for reverse thrust during the
RTO is allowed, however, regulations do allow the credit for reverse thrust on a
wet or contaminated runway. The use of speedbrake is always credited.
For a given runway the Accelerate-Stop Distance Limit Weight is the weight for
which ASDR equals ASDA. At this limit weight the aircraft will just be able to
stop within the ASDA, when maximum braking action is initiated at the latest by
V1, with only the use of speedbrake on a dry runway, and with the additional use
of one T/R on a wet or contaminated runway.
Of course, when actually rejecting a takeoff on a dry runway, the T/R should be
used.
CS-25.101The accelerate-stop (…) distances (…) must be determined with all the aeroplan
Regulation require certification of takeoff performance on a wet runway be
based on tire tread depths of 20% (which is about 2mm) of a new tire.
ASDA may be increased by a stopway.
EU-OPS 1.480Accelerate-stop distance available (ASDA): The length of the take-off run a
Accelerate Stop Distance for a certain TOW
2.2.1.1. Stopway
CS-DefinitionsStopway means an area beyond the take-off runway, no less wide than the r
The maximum takeoff weight of an aircraft may be increased by using the
stopway to increase the ASDA when calculating Field Length Limit TOW.
There is no limit on the length of the available stopway that may be used in
calculating Field Length Limit TOW, except that V1 may never exceed the
maximum tire speed (VTIRE).
RESA [Overview clearway-stopway] may not be used as stopway in
performance calculations.
2.2.2. Takeoff Distance
Also referred to as Accelerate-Go Distance.
Aircraft must be able to safely continue the takeoff following an engine failure at
VEF, and reach V2 at a screenheight of 35 feet at the end of the runway.
Aircraft must also be able to safely take off with all engines operating.
Takeoff Distance Required (TODR): the higher of:
The required distance to accelerate with all (N) engines operating to
VEF,plusthe required distance to accelerate with one engine inoperative (N-1) to
V2 at a screenheight of 35 feet above the takeoff surface,and
One Engine Inoperative Takeoff Distance for a certain TOW
The required distance to accelerate with all (N) engines operating to a
screenheight of 35 feet, plus a distance margin of 15%.
All Engine Takeoff Distance for a certain TOW
For a 2 engine aircraft the one engine inoperative takeoff distance requirement is
normally more limiting than the all engine takeoff distance requirement.
Only in the one engine inoperative case, the screenheight may be reduced to 15
feet when the runway is wet or contaminated.
In the all engine takeoff case the speed at the 35 feet point will be greater than
the scheduled safe flying speed, V2.
For a given runway the TOD Limit Weight is the weight for which TODR equals
TODA. At this limit weight a 2 engined aircraft will just be able to reach the
required screenheight at the end of the TODA, when the takeoff is continued
following an engine failure at VEF.
TODA may be increased by a clearway which does not exceed half the TORA.
EU-OPS 1.480Take-off distance available (TODA) The length of the take-off run available
EU-OPS 1.490 The takeoff distance must not exceed the takeoff distance available, with a
2.2.2.1. Clearway
CS-DefinitionsClearway means an area beyond the runway, not less than 152 m (500 ft) w
The maximum takeoff weight of an aircraft may be increased by using the
clearway to increase the takeoff distance available when calculating Field
Length Limit Weight.
The clearway plane extends from the end of the runway with an upward slope
not exceeding 1.25% above which no object or terrain protrudes (except
threshold lights with max height 0,66m (26”) if located at each side of the
runway).
Maximum allowable clearway which may be used in takeoff performance
calculations equals half the takeoff flare distance (where the flare distance is the
distance along the ground from the point where the aircraft is at the liftoff speed
to the point where the aircraft reaches the screenheight) and may not exceed half
the TORA.
Takeoff Flare Distance
Max Allowable CWY ≤ ½ T/O Flare Distance ≤ ½ TORA
Because of the reduced screenheight, regulations do not allow the use of a
clearway on a wet runway (The use of a clearway on a contaminated runway is
not addressed by regulations).
RESA [Overview clearway-stopway] may not be used as clearway in
performance calculations.
2.2.3. Line-up Correction
Line-up corrections: The adjustments made to the available runway length to
account for the fact that some of the runway length is used for aligning the
aircraft on the runway prior to beginning the takeoff roll.
Required to be taken into account any time the access to the runway does not
permit positioning of the aircraft at the runway threshold [EU-OPS 1.490].
Assumes positioning of the aircraft taking the minimum edge safety distance of
the landing gear (10 feet for B737) into account.
Both ASDA and TODA needs to be corrected:
ASDA correction: distance from threshold to nosegear.
TODA correction: distance from threshold to maingear.
Line-up corrections
Generally pilots are provided with takeoff data in which line-up corrections are
already implemented, therefore normally no additional corrections by crew are
required.
2.2.4. Balanced Takeoff
For a given runway (fixed ASDA en TODA), selection of V1 is dependent on the
TOW (Graph 1). Subsequently, for a given (fixed) TOW, both ASDR and TODR
are influenced by selection of V1 (Graph 2).
For a given runway, maximum TOW will be achieved when V1 is selected such,
that the ASDR and the TODR for that TOW are equal (balanced) – at the
intersection of the two lines in Graph 1. This V1 is called Balanced V1 and
corresponding TOW is called Balanced (Takeoff) Weight.
For better understanding, graphs give a simplified presentation.
Graph 1 ~ TOW VS. V1:
The RED line shows the relationship between TOW and V1, for a given ASDA, in
case of a discontinued takeoff. To limit the amount of energy at the moment the
decision to stop is made, a high TOW requires a low V1, in order to be able to
stop within the ASDA. Subsequently, a low TOW allows a high V1.
The GREEN line shows the relationship between TOW and V1, for a given
TODA, in case of a continued takeoff. To limit the acceleration on 1 engine from
V1 to V2, a high TOW requires a high V1, in order to be able to reach V2 at the
screenheight at the end of the TODA. Subsequently, a low TOW allows a low V1.
For a given (fixed) TOW, the required field length is determined by ASDR and
TODR. The lowest required field length is reached where ASDR equals TODR –
at the intersection of the two lines in Graph 2. This is called the Balanced Field
Length.
Graph 2 ~ Field length (TODA/ASDA) VS. V1:
The RED line shows the relationship between required field length (ASDR) and
V1, for a given TOW, in case of a discontinued takeoff. Due to the lower amount
of energy at the moment the decision to stop is made, a low V1 results in a
shorter ASDR, contrary to a high V1.
The GREEN line shows the relationship between required field length (TODR)
and V1, for a given TOW, in case of a continued takeoff. Due to the longer
acceleration on 1 engine from V1 to V2, a low V1 results in a longer TODR,
contrary to a high V1.
Balanced Field Length: ASDR = TODR
2.2.4.1. Unbalancing
Unbalancing: Using any value other than balanced V1.
Unbalancing is optional when not field limited, but may be required when field
limited (in case clearway ≠ stopway).
2.2.4.1.1. Optional unbalancing
Balanced V1 requires the lowest runway length (balanced field length), but if the
actual runway is greater than the balanced field length, a range of V1 is available
(Graph 3).
Graph 3~ Available V1-range for a given TOW:
The dotted yellow line in the graph shows the required runway length which is at
its minimum (and equal to the balanced field length) when using balanced V1.
If V1 is set to the lower limit, the aircraft will stop well before the end of the
runway in case of a rejected takeoff, following an event at VEF, but it would
only just be possible to reach V2 at the screenheight at the end of the runway in
case of a continued takeoff, following an engine failure at VEF.
If V1 is set to the upper limit, the aircraft will reach V2 at the screenheight well
before the end of the runway in case of a continued takeoff, following an engine
failure at VEF, but it would just be possible to stop at the end of the runway in
case of a rejected takeoff following an event at VEF.
Other than balanced V1 may be used to:
increase V1 to above VMCG in order to increase V1MCG Limit TOW.
reduce V1 to below VMBE in order to increase Brake Energy Limit TOW.
Even with a range of V1 available, the absolute upper and lower limit still
applies:
V1 may not exceed VR because no takeoff may be rejected after rotation.
V1 may not be less than VMCG.
2.2.4.1.2. Required unbalancing
ASDA may be increased with a stopway and TODA may be increased with a
clearway in order to increase the TOW. But if stop- and clearway are not equal,
there is no balanced takeoff situation. To use the higher TOW resulting from the
use of clearway and/or stopway, V1 has to be adjusted to be able to meet the
requirements for stop and go. This V1 correction is a function of the difference
between clearway and stopway.
Two situations are distinguished:
Clearway > Stopway: In case clearway exceeds stopway, V1 needs to be
lowered. Starting from the balanced situation, an aircraft with the higher
TOW, resulting from the increased TODA, still needs to be stopped within
the (unchanged) ASDA.
Extreme situation with clearway and no stopway
Clearway > Stopway: decrease V1
Stopway > Clearway: In case stopway exceeds clearway, V1 needs to be
increased. Starting from the balanced situation, an aircraft with the higher
TOW, resulting from the increased ASDA, must still be able to reach V2
within the (unchanged) TODA.
Extreme situation with stopway and no clearway
Stopway > Clearway: increase V1
2.2.4.2. Rebalancing
Actual conditions which differ from the situation for which V1 is published
(level/dry runway at SL, standard day, no wind) require adjustment of V1 in
order to maintain a balanced takeoff.
Conditions causing reduced stopping capability require a lower V1.
The ASDA becomes more restrictive – the decision to abort the takeoff has to be
made earlier to guarantee a safe stop before the end of the runway.
Possible conditions:
Runway surface not being dry
Downsloping runway (see also below)
Inoperative equipment affecting the aircrafts ability to stop (eg. T/R inop)
Reduced stopping capability requires a lower V1
Reduced stopping capability: decrease V1
Conditions causing reduced acceleration capability require a higher V1.
The TODA becomes more restrictive - the decision to continue the takeoff must
be made at a higher speed to make the (reduced) acceleration on one engine
shorter so that V2 can be reached within the TODA.
Possible conditions:
Less available thrust due to high airport elevation or high (actual or assumed)
OAT
Upsloping runway
Deposits on the runway causing drag (eg. slush, standing water)
Reduced acceleration capability requires a higher V1
Reduced acceleration capability: increase V1
Rebalancing V1 requires a longer balanced field length and must therefore be
accompanied by a weight reduction, in order to equal the rebalanced field length
to the standard balanced field length.
EXCEPTION: the reduced deceleration capability of a downslope might be more
than compensated by its increased acceleration capability, resulting in a rebalanced fieldlength shorter than the balanced fieldlength, allowing a higher
Field length limit takeoff weight.
2.2.5. Runway Surface Conditions
2.2.5.1. Dry Runway
EU-OPS 1.480A dry runway is one which is neither wet nor contaminated, and includes th
Grooved or porous friction course runway: A paved runway that has been
prepared with lateral grooving or a porous friction course (PFC) surface to
improve braking characteristics when wet.
EU-OPS 1.475For performance purposes, a damp runway, other than a grass runway, may
EU-OPS 1.480A runway is considered damp when the surface is not dry, but when the mo
Damp is a runway condition when the runway is drying up following rain or
when covered with morning dew as indicated by a color change.
A damp runway or a wet grooved or PFC (Porous Friction Course) runway may
not yield the same level of performance as a dry runway.
2.2.5.2. Wet Runway
EU-OPS 1.480A runway is considered wet, when the runway surface is covered with wate
A runway is considered wet as soon as it has a shiny appearance, but without risk
of hydroplaning due to standing water (or other fluid) on any part of its surface.
The aircraft's acceleration is not affected, but the stopping capability is degraded
due to the reduction in tire to ground friction, therefore:
V1 needs to be rebalanced to a lower value in order to be able to stop the aircraft
before the end of the runway in case of a discontinued takeoff. [PRH A1-2.2.4.2.
Rebalancing]
Field Length Limit TOW needs to be lowered, in order to reduce the increased
balanced field length, resulting from the rebalanced V1, to within the runway
limits.
Credit for the use of reverse thrust on the operative engine during an aborted
takeoff following an engine failure is allowed.
The screen height to be reached at the end of the takeoff distance is lowered to
15 feet (instead of 35 feet on a dry runway).
Same TODR and ASDR for dry and wet runway takeoff
Because of the lower screenheight, the use of clearway on a wet runway is not
allowed.
The TOW on a wet runway must not exceed that permitted for a takeoff on a
dry runway under the same conditions. Therefore a Dry Check is required to
exclude the theoretical possibility that, due to credits for reverse thrust and use
of a reduced screen height, a higher takeoff weight is obtained on a wet runway
than on a dry runway, which is not allowed.
2.2.5.3. Contaminated Runway
EU-OPS 1.480 A runway is considered to be contaminated, when more than 25% of the ru
Surface contaminants can be classified as: fluid and hard contaminants.
2.2.5.3.1. Fluid Contaminants
Fluid contaminants: Contaminants with a measurable depth which are drag
producing and tire braking friction reducing.
Aircraft runs through the contaminant, causing drag and reducing braking
friction, affecting both acceleration and deceleration.
Drag is caused by displacement of the contaminant and by impingement of the
displaced contaminant spray on the fuselage and/or wings.
Airplane tire on runway contaminated with fluid contaminant
The slush drag force (FSLUSH) increases with the square of the aircraft’s
groundspeed (VG) and peaks just above the hydroplaning speed (VHP) - speed
at which the tire starts to lift out of the fluid contaminant (resulting in ineffective
wheelbrakes) - and then decreases with further speed increase.
VHP = 8.63√P [P is tire pressure in psi]
B737 hydroplaning speed is approximately 120 kts.
Hydroplaning (Aquaplaning): Partial or total loss of contact and friction between
the tire and the runway which occurs when the tire cannot squeeze anymore of
the fluid contaminant layer between its tread and lifts off the runway surface.
To assure a safe operation from a runway contaminated with a fluid contaminant,
the TOW needs to be reduced to compensate for the reduced acceleration
capability and the reduced braking capability.
Since the reduced stopping capability (requiring a lower V1) is more significant
than the reduced acceleration capability (requiring a higher V1), V1 needs to be
rebalanced to a lower value [PRH A1-2.2.4.2. Rebalancing], but the V1adjustment becomes less negative with increasing contaminant depth due to
increasing significancy of the reduced acceleration capability.
Contaminants of this kind are:
Standing water
EASA/AMC-25.1591Water of a depth greater than 3mm.
Specific gravity: Relative density defined as the ratio of the density of a given
substance to the density of water when both substances are at the same
temperature. Substances with a specific gravity greater than 1 are more dense
than water, and those with a specific gravity of less than 1 are less dense than
water. Expressed as a dimensionless value.
Typical temperature is above 0°C (32°F)
Slush
EASA/AMC-25.1591Partly melted snow or ice with a high water content, from which wat
Normally a transient condition found only at temperatures close to 0°C (32°F).
Wet snow
EASA/AMC-25.1591 Snow that will stick together when compressed, but will not readily
Typical temperature for wet snow to be present is between -5°C (23°F) and -1°C
(30°F).
Dry (loose) snow
EASA/AMC-25.1591 Fresh snow that can be blown, or, if compacted by hand, will fall ap
The assumption with respect to specific gravity is not applicable to snow which
has been subjected to the natural ageing process.
Typical temperature for dry (loose) snow to be present is below -5°C (23°F).
2.2.5.3.2. Hard contaminants
Hard contaminants: Solid contaminants with no measurable depth (depth is not
relevant) which are tire braking friction reducing.
Aircraft runs on the contaminant, causing only reduced braking friction (no extra
drag), affecting only the deceleration.
Airplane tire on runway contaminated with hard contaminant
To assure a safe operation from a runway contaminated with a hard contaminant,
the TOW needs to be reduced to compensate for the reduced braking capability
and V1 needs to be re-balanced to a lower value.
Contaminants of this kind are:
Compacted Snow
EASA/AMC-25.1591Snow which has been compressed into a solid mass such that the aer
Ice
EASA/AMC-25.1591Water which has frozen on the runway surface, including the conditi
2.2.5.3.3. Regulation allowances and restrictions on contaminated runways
Regulation allowances to reduce the performance effects (which result in a
weight penalty) on contaminated runways:
Credit for the use of reverse thrust on the operative engine during an aborted
takeoff following an engine failure is allowed.
The screen height to be reached at the end of the takeoff distance is lowered to
15 feet (instead of 35 feet on a dry runway).
Regulation restrictions:
The use of Assumed Temperature reduced thrust is not allowed on
contaminated runways.
2.2.5.3.4. V1MCG Limit Weight
If V1 is adjusted to compensate the reduced braking capability on a
contaminated runway, a check is required to ensure that the adjusted V1 is not
less than VMCG.
If the adjusted (required) V1 is lower than VMCG, it must be set equal to
VMCG. In such a case, the resulting (higher) V1MCG requires more runway
length than was required for the adjusted V1. If the increased required length
exceeds the ASDA, the takeoff weight must be limited in order to be able to stop
within the ASDA limits in case of a RTO.
For a given available runway length (ASDA), there will be a limit weight for
which V1 is equal to VMCG: V1MCG Limit Weight. FCOM/PI provides
V1MCG limit weights and it must be checked that this weight is not exceeded.
V1MCG Limit Weight: The maximum weight for which the airplane can
accelerate to VMCG and just be able to stop within the available accelerate stop
distance.
V1MCG Limit Weight
If VMCG limited, the use of Derated (not Reduced) takeoff thrust might increase
V1MCG Limit Weight.
2.2.5.3.5. Additional considerations
Because the contamination on the runway is only influencing the aircraft while
still on the ground, the reduced Field Length Limit TOW will result in a higher
climb capability, hence greater obstacle clearance, once the aircraft is airborne.
Better climb performance due to reduced (Field Limit) TOW
Regulations do not address the use of clearway on a contaminated runway, but
consider the following:
Applying the contaminated runway performance adjustments to the dry Field
Length Limit TOW, the reduced TOW, along with the associated V1 adjustment,
results in the same TODR to reach 15 feet as the dry Field Length Limit TOW
would take to reach 35 feet. So, if the dry Field Length Limit TOW takes credit
for clearway, the height over the end of the runway following an engine failure at
the critical point will be lower than 15 feet. In fact, the height over the end of the
runway could be as low as zero at the liftoff end of the runway.
Possible low runway end crossing height on contaminated runway
2.3. CLIMB REQUIREMENT
Regulations require minimum climb gradients in the takeoff flight path,
assuming an engine failure at VEF under NO WIND conditions.
2.3.1. Takeoff Flight Path
The takeoff path can be divided into the takeoff distance and the takeoff flight
path. The climb requirement addresses the takeoff flight path.
CS-25.111 The take-off path extends from a standing start to a point at which the aeroplan
CS-25.115 The takeoff flight path begins 35 ft above the take-off surface at the end of the
Boeing takes minimum clean speed (VREF40 + 70kts) as final takeoff speed.
The takeoff flight path is divided into 4 segments, each being characteristic of a
distinct change in configuration, thrust and speed, based on performance without
groundeffect and zero-wind conditions.
Per segment, regulations require a minimum climb gradient, assuming an engine
failure at VEF under NO WIND conditions.
Any of these climb requirements may limit the maximum TOW. If a requirement
cannot be met, TOW must be reduced until the aircraft climb performance meets
the climb requirements (Climb Limit TOW).
Climb Limit TOW: A takeoff weight which is limited by the ability of the
airplane to achieve the minimum required climb gradient with one engine
inoperative in still air.
Climb gradient: The ratio, expressed as a percentage, of the change in geometric
height divided by the horizontal distance travelled in a given time.
As a rule of thumb, the actual climb gradient can be checked in flight by
dividing the actual vertical speed (in ft/min) by the actual groundspeed (in kts).
2.3.1.1. First Segment
Extends from the end of the takeoff distance to the point where the landing gear
is assumed to be fully retracted, using takeoff flaps at a constant V2 speed.
Thrust of remaining engine is at TO/GA thrust.
1st Segment: Required Climb Gradient > 0 [CS-25.121 (this requirement is
applicable from liftoff)]
2.3.1.2. Second Segment
Extends from the gear up point to a gross height of at least 400 feet (max 1500
feet), using takeoff thrust on the remaining engine and takeoff flaps at a constant
V2 speed.
2nd Segment: Required Climb Gradient ≥ 2.4% [CS-25.121]
For a 2-engine aircraft, this requirement is typically the most limiting.
May be extended above 1500 feet AAL to clear obstacles in the 3rd segment,
provided MCT is sufficient to maintain the required climb gradient in the 3rd
segment.
2.3.1.3. Third Segment
The horizontal distance required to accelerate, at constant altitude using takeoff
thrust on the remaining engine, to the final climb speed while retracting flaps in
accordance with the recommended speed schedule.
According CS-25.111 the available climb gradient above 400 feet AAL must be
a minimum of 1.2%.This requirement can be transformed into a level
acceleration.
3rd Segment: Level acceleration
Level-off height is determined by:
Regulations: Minimum 400 feet AAL
Company policy
Obstacles
TO/GA thrust time limit:
The use of TO/GA thrust is normally limited to 5 minutes. For single engine
operations this time limit may be increased to 10 minutes, provided the
availability of an AFM Appendix where this is stated.
If TO/GA thrust is needed to maintain the required gradient capability, the time
limit on the use of TO/GA thrust defines the maximum level-off height.
If TOW is limited by the TO/GA thrust time limit, MTOW will be increased by
the use of improved climb.
If MCT is sufficient to maintain the required gradient capability, the 2nd
segment may be extended beyond this maximum level-off height – Extended
Second Segment – which can be used to clear obstacles that lie in the 3rd
segment.
2.3.1.4. Final Segment
Extends from the end of the third segment to a gross height of at least 1500 feet,
with flaps up, maximum continuous thrust on the remaining engine and at final
climb speed.
Final Segment: Required Climb Gradient ≥ 1.2% [CS-25.121]
Final segment, and thereby the takeoff (flight) path, is completed when the
aircraft has reached 1500 feet AAL or the altitude at which the transition from
the takeoff to the enroute configuration is completed and VMINCLEAN is
reached, whichever is higher.
2.3.2. Improved Climb
Improved Climb: Trading excess runway for higher takeoff speeds to increase
the aerodynamic efficiency, resulting in better climb performance.
Only applicable when takeoff performance is not limited by the field length
requirement, leaving excess runway available.
This improved climb capability can be used to increase Climb Limit TOW and
might also increase the Obstacle Limit TOW.
To achieve the higher V2, the rotation speed, VR, must be increased.
Due to the increased weight, V1 must be increased to ensure that, if an engine
fails at VEF, the aircraft has sufficient speed to continue the takeoff.
Speeds can be increased up to the point where the Field Length Limit TOW and
Tire Speed Limit TOW becomes more limiting than the Climb Limit TOW. If the
resulting V1 exceeds VMBE the improved TOW must be adjusted.
Because improved climb speeds are higher than the standard takeoff speeds, the
takeoff speeds from FMC and FCOM cannot be used and have to be obtained
from the FPPM or a special TL chart.
2.3.2.1. Advantages of improved climb
The primary benefit of improved climb is the increase in Max Allowable TOW
when the performance is limited by the required climb gradient or obstacles.
Instead of a higher weight, the increased performance can also be used to apply
less thrust (higher assumed temperature or lower thrust rating).
The max assumed temperature where a B737-700/24K becomes climb limited
will increase by 8˚ when improved climb is used.
A higher VLOF results in an increased tail clearance (higher speed requires
lower pitch attitude for the same lift).
Eg.B737-900: 5kts VLOF increase requires 1 degree less pitch attitude
representing 10 inch increased tail clearance.
Distant obstacles become less limiting.
Regarding the 10 minute TO/GA-thrust time limit, the end of the third takeoff
segment is reached at a higher altitude, allowing a higher maximum level off
height.
The faster and steeper climb out reduces noise (in duration and intensity) on the
ground (except for close-in noise monitoring).
Effect of improved climb on obstacle clearance.
2.3.2.2. Disadvantages and restrictions
Due to using more excess runway, the RTO stopping margin is reduced.
Close-in obstacles can become more limiting.
Tire wear increases due to longer ground roll and higher speeds.
A higher VLOF decreases the margin to VTIRE (resulting in lower Tirespeed
Limit Weight) and a higher V1 decreases the margin to VMBE (resulting in
lower Brake Energy Limit Weight).
Due to higher speeds, there is an increased chance of being limited by brake
energy (which limits V1) or tire speed limitations (which limits VLOF, thus VR).
VTIRE might inadvertantly be exceeded by slow rotation.
Use of reduced thrust or weight corrections for a contaminated runway, is not
allowed in combination with improved climb performance.
Dispatch with antiskid inoperative in combination with improved climb is not
allowed.
OVERVIEW TAKEOFF FLIGHT PATH SEGMENTS
2.4. OBSTACLE CLEARANCE REQUIREMENT
All obstacles in the Obstacle Accountability Area (OAA) or Departure Sector
have to be taken into account prior to takeoff to ensure that the aircraft will be
able to clear them, with one engine inoperative.
OAA is defined by the lateral clearance criteria as stated in EU-OPS and extends
to the point at which the aircraft attains a net height of 1500 feet AAL.
Obstacle Accountability Area for trackchange ≤ 15°
For departures with trackchanges > 15°, the OAA is curved along the track and
wider (up to a total width of 1800m or 1200m with sufficient NAVAID
accuracy).
EU-OPS 1.495An operator shall ensure that the net takeoff flight path clears all obstacles b
Regulations require that the Net T/O Flight Path clears all obstacles in the
Departure Sector by a minimum vertical distance of 35 feet or, if the bank angle
is greater than 15°, by 50 feet.
Net T/O Flight Path: Theoretical flight path starting at the end of the TODA at
35 feet.
Gross T/O Flight Path: Actual flight path with one engine inoperative.
For a 2 engine aircraft, regulations require the Gross T/O flight path to have a
0.8% greater penalty than the Net T/O flight path gradient, to account for
average pilot skill and average airplane performance.
Vertical obstacle clearance requirement
Obstacles in the Final Takeoff Segment may be avoided by turning.
The most penalizing obstacle determines the Obstacle Limit TOW.
2.4.1. Emergency Turn
Where obstacles in the takeoff path would severely disrupt operations, a special
Engine Failure Procedure, or Emergency Turn may be developed by the
company.
PANS-OPS 8168Development of contingency procedures, required to cover the case of en
In such a case, a SID deviation point can be identified. [IEM-OPS 1.495]
SID deviation point: A specified point on the SID where the engine failure route
deviates from the normal departure route.
To cover the situation that an engine fails on the SID beyond the SID deviation
point, the operator may also define a SID restriction point, since the achievable
climb gradient with one engine inoperative may not be sufficient to achieve the
required SID gradient.
Meeting a SID climb gradient (standard is 3.3%) does not necessarily assure that
one-engine-inoperative obstacle clearance requirements are met.
SID restriction point: A specified point (or altitude) on the SID after (or above)
which following the SID assures sufficient obstacle clearance with one engine
inoperative.
Note from the graph below that the climb performance (which is a function of
excess thrust – i.e. thrust minus drag) with both engines operating is about 4
times better than with one engine inoperative. Therefore the engine failure
situation heavily depends on what altitude is already gained on both engines
before an engine fails.
2.4.2. Additional Consideration
Since takeoff from a wet or contaminated runway is based on a screenheight of
15 feet - where the Gross (actual) Flight Path starts - and the Net flight path is
defined to start at the 35 feet point, the aircraft may clear a close-in obstacle with
less than 35 feet, but at least with 15 feet.[IEM-OPS 1.495]
Obstacle clearance with reduced screenheight
2.5. TIRE SPEED REQUIREMENT
Maximum certified tire speed limitation restricts the maximum speed of the
aircraft while on the ground (VLOF) which restricts the VR, which in turn
restricts the TOW.
With a restricted VR, the amount of lift that can be produced to counteract the
weight is also restricted, thereby limiting the TOW.
Tire Speed Limit TOWrepresents a weight requiring a liftoff speed equal to the
tire speed limit.
B737 certified tire speed is 225 mph / 195 kts.
Reducing VLOF can be performed by: Reducing TOW Increasing takeoff flap setting
Tire speeds can be limiting on hot and high airports or when Improved Climb
Performance is used.
When operating at or near the Tire Speed Limit TOW, a slower rotation than the
recommended 2-3°/sec may increase the actual groundspeed at liftoff beyond the
certified tire speed limit.
2.6. MAXIMUM BRAKE ENERGY
REQUIREMENT
Maximum Brake Energy speed(VMBE) represents the maximum speed, for a
given TOW, at which the brakes are able to absorb the built-up energy (which is
a function of weight and speed) and still be effective.
Maximum possible energy absorption occurs at V1 during an RTO, therefore
maximum V1 is restricted by VMBE.
If V1 exceeds VMBE, reducing V1 can be performed by:
Reducing TOW
Unbalancing [PRH A1-2.2.4.1. Unbalancing]
3. REDUCED TAKEOFF THRUST
SAVING YOUR ENGINES
Engines contribute about 66% to the aircraft performance deterioration,
therefore:
Reducing the takeoff thrust whenever possible is a major tool for pilots to
increase engine reliability (improving flight safety) and decreasing
(maintenance) costs.
Using a lower than full rated (i.e. derated or reduced) takeoff thrust is a way of
saving engine life.
3.1. ENGINE CHARACTERISTICS – CFM Notes
To meet aircraft performance requirements, the CFM56 engine (mounted on a
Boeing 737) is a flat-rated engine: Producing constant TO/GA thrust up to the
Flat-Rated Temperature (FRT) or Corner Point OAT. Both N1 and EGT increases
with OAT up to the FRT, beyond which N1 decreases and EGT remains constant.
FRTCFM56 = ISA + 15°C (27°F)
EGT Margin: the difference between the EGT Red Line and the EGT, observed
on an engine at TO/GA thrust with OAT greater than the Corner Point OAT.
EGT Margin is representative of the engine life:
Engine deterioration results in a lower EGT margin and hence lower OAT limit,
which increases the possibility of EGT (red line) exceedance.
In case the OAT Limit becomes less than the FRT, EGT exceedance may occur
during a full thrust takeoff.
A decreasing EGT margin increases the fuel burn.
CFM: An EGT margin decrease of 10°C (18°F), which corresponds to 3000 engine cycles,
Keeping the EGT margin as large as possible will improve the flight safety (less
engine deterioration) and lower the maintenance costs due to an increase of the
“Time On Wing” (number of cycles before an engine overhaul or replacement is
needed).
EGT margin of a new CFM56 (27K) engine is about 60°C (108°F). A decrease
of 10°C (18°F) per 3000 cycles (from idle to full thrust and back to idle) result in
an average Time On Wing of 18000 cycles.
Pilot-tools to maintain the highest possible EGT margin are:
Allow enough time for the engine to cool down.
Insufficient cooling time will result in the high pressure turbine blades scraping
the (quicker) cooled engine casing after shutdown, hence increasing the tip
clearance (space between the turbine bladetip and the engine housing). Due to
the increased air leakage, a larger tip clearance results in a less efficient engine
which can be noticed by a higher fuelflow and a decreased EGT margin.
CFM: An HP turbine tip clearance increase of 0.25 mm (0.01”) results in a 10°C (18°F) le
CFM recommends a cooling time, at or near idle, of at least 3 minutes (taxi time
included) after landing.
Perform, whenever possible, a reduced thrust takeoff.
Lower N1 values result in lower EGTs.
CFM: At given OAT, 1% N1 is equivalent to approximately 10°C (18°F) EGT.
Reducing engine thrust by assuming a higher than actual OAT also has a positive
effect on the EGT, hence EGT margin.
CFM: 1°C (2°F) OAT or Assumed Temperature is equivalent to 3.5°C (6°F) EGT.
3.2. TAKEOFF THRUST REDUCTION
Anytime the Performance Limit TOW is greater than the Actual TOW, there is a
possibility to reduce the takeoff thrust and still meet the regulatory requirements
for takeoff performance.
PLTOW > Actual TOW: Reduced takeoff thrust possible
Two possible ways of reducing the takeoff thrust are by a fixed Derate and by a
flexible thrust reduction - the Assumed Temperature Method.
3.2.1. Derated Takeoff Thrust (fixed)
EASA/AMC 25-13 Derated take-off thrust, for an aeroplane, is a take-off thrust level less t
The engine will be operating at a defined lower thrust rating, just as if the
aircraft was equipped with less powerful engines.
Derate value can be altered by the crew reprogramming the FMC, but this option
might be inhibited to avoid the possibility of an unwanted combination of an
assumed temperature with a derate thrust level.
Depending on the level of full rated thrust, there are up to two derates possible.
Derate thrust level will be considered to be a new maximum and may not be
exceeded.
DErate is not the same asRErate the engine (change the approved engine thrust)
which can be mechanically done by the manufacturer or by maintenance.
Since VMCG has to be calculated with maximum TO/GA thrust, a Derate thrust
level (lower maximum) results in a lower VMCG, hence a higher V1MCG Limit
weight. [PRH A1-2.2.5.3.4. V1MCG Limit Weight]
If thrustlevers are advanced to beyond the Derate thrust limit, directional control
problems might occur when an engine fails during the takeoff roll.
Disadvantage: for each of the available thrust ratings, separate data (TL-charts)
must be available in order to select the appropriate derate.
3.2.2. Reduced Takeoff Thrust - Assumed
Temperature Method (ATM)
EASA/AMC 25-13 Reduced take-off thrust, for an aeroplane, is a take-off thrust less than
ATM is a flexible way of reducing the takeoff thrust – depending on the situation
– and is based on assuming a higher than actual temperature resulting in a lower
thrust output of the engines.
Assumed Temperature (TASSUMED) varies with actual TOW, engine thrust
rating, engine bleed demand, flap setting and different runways/intersections.
Reduced thrust based on an TASSUMED is not a limit – pilots may advance the
thrust levers to the TO/GA-thrust setting for the actual OAT (eg. in N-1
operations).
3.2.2.1. Performance Margins
Using the max allowable TASSUMED, still leaves performance margins, due to
true airspeed and thrust effects.
True Airspeed Effect
TAS is affected by OAT. IAS is based on air pressure difference in the pitot static
system. Due to a higher air density at low OAT, a slower airflow is sufficient to
generate the pressure difference needed to reach a given IAS, resulting in a
lower TAS. The opposite is true for a high OAT.
When assuming a higher than actual OAT, the resulting takeoff performance is
based on a higher TAS, but the actual TAS will be lower (because the actual
OAT is lower).
Thrust Effect
A high-bypass turbofan engine, as mounted on the B737, produces about 80% of
the total thrust by accelerating air mass through the fan. Higher air density, hence
higher air mass, results in higher thrust.
When assuming a higher than actual OAT, the resulting takeoff performance is
based on a lower air density and therefore lower thrust, but the actual thrust will
be higher (because of the actual higher air density).
A lower TAS combined with a higher thrust will result in:
Shorter ground distance
Higher climb gradient
Margins when using ATM
Using the Assumed Temperature Method is always conservative because the
actual performance of the airplane is always better than its assumed capabilities
even at the maximum allowable assumed temperature.
These performance margins exist anytime TASSUMED (if > FRT) exceeds OAT.
The greater the difference between OAT and TASSUMED, the greater the
performance margin.
These performance margins are not available when using the Derate method.
To achieve the available performance margins, proper takeoff speeds have to be
used; overspeed will reduce those available margins.
Using these inherent margins for takeoff weight planning is prohibited.
3.2.2.2. Restrictions
The amount of thrust reduction is restricted by the following:
Regulations
VMCG and VMCA must be calculated at the TO/GA-thrust for the actual OAT.
EASA/AMC 25-13The reduced take-off thrust setting enables compliance with the aeropla
Reduced thrust takeoffs are not allowed on contaminated runways, but, if
suitable data is available, are allowed on wet runways.
EASA/AMC 25-13Takeoffs utilising reduced take-off thrust settings are not authorised on
Maximum allowable TASSUMED is the lower of the performance-limited
temperature, and the temperature which results in 25% thrust reduction.
EASA/AMC 25-13The reduced take-off thrust setting is at least 75% of the take-off thrust
The use of reduced thrust is also not allowed when certain items cause a
significant workload increase.
EASA/AMC 25-13Take-offs utilizing reduced take-off thrust settings are not authorised w
Regulations do allow application of full thrust whenever desirable.
EASA/AMC 25-13When conducting a take-off using reduced take-off thrust, take-off thru
EASA/AMC 25-13 Application of reduced take-off thrust in service is always at the discr
Performance Limits
PLTOW decreases with decreasing takeoff thrust. The amount of thrust reduction
will be limited to the situation where the PLTOW equals the Actual TOW.
Engine limits
Using an TASSUMED less than the FRT will not result in less thrust.
TASSUMED < FRT: No thrust reduction
The FRT is the minimum assumed temperature which still results in a thrust
reduction.
Company restrictions
Your company might have additional restrictions on the use of reduced thrust.
3.2.2.3. Reduced thrust and speeds
Consequences of reduced takeoff thrust for the takeoff speeds are:
Higher V1
Reducing the takeoff thrust results in a reduced acceleration capability. In order
to preserve the field length requirement a higher V1 shall be used. [PRH A12.2.4.2. Rebalancing]
Lower V2
Reducing the takeoff thrust results in less (excess) thrust available to reach
standard V2 at the screenheight. In order to preserve the desired field length,
obstacle and/or climb requirement a lower V2 shall be used.
3.2.2.4. Reduced thrust and trim
Since the trim setting for takeoff is based on full thrust, normally a pitch up trim
movement is required after takeoff with reduced thrust.
3.2.3. Combination Derate and Reduced thrust
This is a method of thrust reduction which consists of applying the assumed
temperature method on a derated thrust level.
The derate thrust level is a maximum and may not be exceeded.
Maximum allowed thrust reduction is 25% of the derate thrust level.
1. GENERAL
CLIMB AND CRUISE
1.1. COST INDEX
Cost Index (CI): Parameter which reflects the relationship between time-related
costs versus fuel costs.
Cost Index = Time-related costs / Fuel costs
Used to minimize the Direct Operating Costs (total costs) which are divided into
time related costs, fuel costs and fixed costs. Fixed costs are not part of CI
calculation.
Low CI: low speed, low fuelburn, high triptime.
Will be used when time related costs are low or the fuel cost are high.
High CI: high speed, high fuelburn, low triptime.
Will be used when the time related costs are high or the fuel cost are low.
1.2. ENROUTE CLIMB
Enroute climb speed depends on weight and CI.
High weight or high CI will result in a higher enroute climb speed.
Enroute climb speed depends on weight and CI
Climbing with a constant IAS results in an increasing TAS. Climbing with a
constant Mach number will result in a decreasing TAS.
Around 29.000 ft lies the crossover altitude where the climbspeed changes from
IAS to Mach number.
IAS / Mach number versus altitude
1.3. CRUISE ALTITUDE
Choosing the best altitude will maximize the fuel or cost efficiency and will
ensure that adequate speed margins are preserved.
Altitude selection depends on:
Fuel/cost efficiency
Thrust limits
Maneuver capability
Trip distance
Altitude winds
1.3.1. Optimum altitude
Optimum Altitude: Altitude which offers the highest fuel mileage (or specific
range).
Fuel Mileage (Specific Range): The distance the airplane can fly using a given
amount of fuel.
Maximum fuel mileage means minimum trip fuel. Varies with the airplane's
weight. Regarding fuel mileage, a lower weight yields a higher optimum
altitude.
Altitude which offers the lowest costs is also an optimum altitude and may not
be the same as the altitude offering the highest fuel mileage.
Optimum altitude which balances the costs and the fuel mileage is determined by
the cost index.
Cost Index decrease: Optimum Altitude increase
Efficiency is maximized when the aircraft stays within a bandwidth (normally
+/- 2000 feet, in RVSM-airspace +/- 1000 feet) around the optimum altitude.
Step climb to stay close to the optimum altitude
1.3.2. Maximum Altitude
The maximum altitude at which the aircraft is able to operate is constrained by
available thrust (thrust limited altitude) and maneuver (or buffet) margin
(maneuver-margin limited altitude).
Thrust limited altitude
Due to decreasing air density, available thrust decreases with increasing altitude.
The thrust limited altitude is the highest altitude the airplane can maintain at the
Maximum Cruise Thrust rating or climb to at the Maximum Climb Thrust rating.
Calculation of the thrust limited altitude is based on a residual rate-of-climb of
100 fpm in cruise or 300 fpm in climb.
Maneuver margin limited altitude
Maneuver margin is the number of g's the airplane could experience before
entering buffet. [e.g. 1.2 g-margin means initial buffet would be expected upon
reaching a steady 34 degree bank (1/cos34 = 1.2)].
Margin to initial buffet decreases with increasing altitude. Due to a wingload
increase (caused by maneuvering or turbulence), a lower buffet margin could
result in buffet, or stall.
Limited by (EASA) regulations: 1.3g (up to 1.6g is airline option).
The standard default FMC buffet margin value is 1.3g.
The default value of cruise CG on the FMC-CRZ page shows the minimum
forward flight (most unfavorable) CG (~ 5-8% MAC), which may be
overwritten.
In order to be able to have the correct actual maximum altitude displayed on the
FMC-CRZ page, the correct actual cruise CG must be entered in the FMC. A
realistic value of cruise CG can be obtained by assessing the CG travel with fuel
burn.
The FMC does not take stick shaker speeds into account when calculating
maximum altitude.
737NG CG travel with fuel burn
1.4. CRUISE SPEED
For a given altitude, the fuel efficiency the airplane can achieve in cruise
depends on the cruise speed. Very low speeds are relatively inefficient, as are
very high speeds. The fuel mileage depends on airplane weight.
1.4.1. Maximum Range Cruise
Maximum Range Cruise speed (MRC): The speed at which, for a given weight,
the highest possible fuel mileage is achieved.
MRC is the speed with Cost Index = 0.
MRC decreases with decreasing weight due to fuel burn. To achieve the
maximum range possible when flying at a constant altitude, the Mach number
needs to be adjusted to correspond to the change in weight.
1.4.2. Long Range Cruise
Long Range Cruise speed (LRC) is a speed higher than MRC with only a slight
increase in fuel consumption.
LRC has a 1% less fuel mileage but is typically 3 to 5% higher than MRC. The
1% loss compared to the maximum fuel mileage is largely compensated by the
cruise speed increase.
Operating at MRC speed requires constant thrust adjustments due to lack of
speed stability. LRC speed offers improved speed stability (less thrust lever
activity).
As with the MRC, the LRC also decreases with decreasing weight.
1.4.3. Economic Cruise speed (ECON speed)
ECON speed: Speed based on the cost index, therefore offering the least costs.
Can vary from a low speed of MRC at a cost index of zero to the Cruise Thrust
limit speed at a high cost index. [PRH A2-1.1. Cost index]
Cost Index decrease: ECON Speed decrease
Is also a function of gross weight, altitude and the actual winds, so it will change
during the flight as fuel burns, the wind changes or a different altitude is
selected.
A strong tailwind will result in a reduced ECON speed in order to maximize the
advantage gained from the tailwind during cruise. Conversely, a higher ECON
speed is calculated in case of a headwind in cruise to minimize the time-related
costs associated with the headwind.
Tailwind increase: ECON Speed decrease
Headwind increase: ECON Speed increase
Typical airline cost index values result in a cruise speed between MRC and LRC.
2. ENROUTE PERFORMANCE REQUIREMENTS
DRIFTDOWN
2.1. GENERAL
Enroute performance requirements address the aircraft capabilities in case of an
engine failure in the enroute phase of flight.
If an engine fails during flight, the required thrust to maintain the altitude
becomes greater than the available MCT of the remaining engine.
The aircraft has to descend to a lower altitude where, due to the higher density,
the remaining engine can produce more thrust and is able to equal the required
thrust to compensate the drag.
Lower altitude – higher density – more available thrust
2.2. DRIFTDOWN
If after an engine failure the aircraft is unable to maintain sufficient terrain
clearance, within the prescribed corridor width along the route, a driftdown
procedure should be followed.
The driftdown procedure consists of the following steps:
Setting of MCT on the remaining engine,
Decelerating to the optimum driftdown speed, while maintaining altitude,
Descending with this speed until reaching the driftdown ceiling (level-off
altitude).
The optimum driftdown speed offers the best lift-to-drag ratio and should be
used in cases where staying as high as possible for as long as possible is
desirable due to terrain or weather concerns.
Driftdown Ceiling: The maximum altitude that can be flown at the driftdown
speed with one engine inoperative.
Using a higher than optimum driftdown speed will result in a slightly steeper
descent path and a lower level-off altitude.
After driftdown, flying LRC-speed offers the best fuel mileage and range.
Higher driftdown speed – lower level-off altitude
2.3. REGULATIONS
2.3.1. Vertical clearance
Regulations define a Net and Gross driftdown flightpath.
Net Driftdown Flightpath: A theoretical flightpath which must clear all obstacles
vertically with at least 2000 feet during descent and with at least 1000 feet after
level-off and must maintain level flight at least 1500 feet above the airport of
intended landing, meeting weather and landing performance requirements.
If weather conditions require its use, the effect of anti-ice systems on the net
flight path must be taken into account.
The Gross (actual) driftdown flightpath gradient must be 1.1% (for a 2-engine
aircraft) more penalizing than the Net driftdown flightpath gradient.
Driftdown requirements
2.3.2. Lateral Clearance
Regulations require that within 5NM either side of the intended track, all terrain
must be considered with regard to obstacles that have to be cleared.
EASA’s requirement of 5NM has to be increased to 10NM if certain navigational
accuracy requirements are not met.
For all routes to be flown a route study is necessary to evaluate whether or not an
acceptable escape procedure is possible when a failure occurs at the most critical
point along the route.
If, on a certain route, the above mentioned requirements cannot be met, the
aircraft weight will be restricted for that specific route or a new route must be
found.
1. GENERAL
LANDING DISTANCE AND SPEED
1.1. LANDING DISTANCE AVAILABLE (LDA)
EU-OPS 1.480Landing Distance Available (LDA): The length of the runway which is decl
The stopway cannot be used for landing calculation.
In cases where there are no obstacles under the landing path the LDA is equal to
the runway length (TORA).
The LDA may be shortened due to the presence of obstacles under the landing
path.
If there is an obstacle present in a specified protection area (approach funnel) in
front of the runway, a displaced threshold is defined. In such cases the LDA is
equal to the length measured from the displaced threshold to the end of the
runway.
The runway part before the displaced threshold may be used for taxiing, takeoff
and landing roll-out.
Displaced threshold due to obstacle in approach path
1.2. LANDING SPEED
1.2.1. Reference Speed (VREF)
Reference Speed(VREF): The reference landing approach speed for a defined
landing configuration.
This speed must not be less than VMCL, the minimum landing control speed.
VREF ≥ VMCL
CS-25.149VMCL, the minimum control speed during approach and landing with all engin
VREF must also be at least 23% greater than the reference stall speed in landing
configuration (VSR0).
VREF ≥ 1.23 VSR0
Because VREF is based on the stall speed, it depends directly on the airplane’s
gross weight.
The threshold speed is VREF for certification and FAS in the actual operation.
1.2.2. Final Approach Speed (FAS)
Final Approach Speed (FAS) is based on VREF.
Final Approach Speed(FAS): The airspeed to be maintained down to 50 feet over
the threshold.
FAS = VREF + correction
This correction is normally based on operational factors such as wind, but can
additionaly be based on an abnormal (landing) configuration.
The wind correction is typically half the steady headwind component (with a
minimum of 5 knots) plus the full gust increment. cumulatively limited to 20
knots, or the resulting FAS is limited to 5 knots below the landing flap placard
speed.
FAS = (VREF + ½ HWC + Gust)
(VREF + 5) ≤ FAS ≤ (VREF + 20) ≤ (Flap placard speed – 5 kts)
Touchdown will normally occur at a speed between VREF and VREF minus 5
knots. An applicable gust increment needs to be maintained until touchdown.
Landing Speeds
2. LANDING PERFORMANCE REQUIREMENTS DISPATCH
MAXIMUM ALLOWABLE LANDING WEIGHT
2.1. GENERAL
Dispatch (planning) requirements are laid down in the EU-OPS regulations and
are designed to make weight calculations in the flight planning stage in such a
way that the crew will not have to make critical performance decisions inflight.
The planning purpose, regarding landing performance, consists of determining
the maximum Landing Weight (LDW) for the destination and alternate
aerodromes which still meets the regulatory requirements.
With respect to landing performance the requirements consider:
landing field length, resulting in a Landing Field Limit Weight (LFLW) [PRH
A3-2.2. Landing field requirement]
approach and landing climb, resulting in a Landing Climb Limit Weight
(LCLW) [PRH A3-2.3. Approach and Landing climb requirement]
The most limiting of these requirements defines the Performance Limit LDW
(PL-LDW) for dispatch and need to be compared to the Max (Certified)
Structural LDW to determine the Maximum Allowable LDW.
Besides these requirements, operation can also be restricted by the maximum
weight for a quick turnaround concerning brake cooling.
The following environmental conditions have to be taken into account:
EU-OPS 1.515 (1) The altitude at the aerodrome; (2) Not more than 50% of the headwind
Normally, pilots are provided with data which already meet the head/tail wind
requirements.
B737NG is limited to operations on runways with a slope not exceeding +/- 2%.
A known aircraft system failure has also to be taken into account.
2.2. LANDING FIELD REQUIREMENT – LFLW
2.2.1. Dispatch Requirements
The dispatch requirements regarding landing field length are laid down in EUOPS 1.515.
EU-OPS 1.515 (a) An operator shall ensure that the landing mass of the aeroplane […] for
Estimated LDW must permit a landing within 60% of the LDA at the destination
and any alternate airport. Herewith, two considerations have to be established in
determining the maximum permissible landing mass, of which the most limiting
determines the Landing Field Limit Weight:
It is assumed that the aircraft will land on the most favorable (normally the
longest) runway under no wind conditions.
When the Estimated Landing Weight (ELW) exceeds the LFLW determined for
the most favorable runway without credit for headwind, dispatch with this higher
ELW to an airport with a single runway is allowed, provided that 2 alternate
aerodromes are selected which fully comply to the dispatch landing
requirements. [EU-OPS 1.515]
If being dispatched with this higher ELW, it must be checked inflight that the
actual LDW upon arrival does not exceed the LFLW, determined with taking the
actual wind into account.[EU-OPS 1.515]
If a different runway is more likely to be assigned as landing runway (due to
expected wind, noise abatement or ATC), it is assumed that the aircraft will land
on this expected arrival runway, where anticipated headwind may be credited but
anticipated tailwind must be taken into account (anticipated wind is the wind
expected to exist at the time of arrival). [IEM-OPS 1.515]
When the Estimated Landing Weight (ELW) exceeds the LFLW determined for
the expected arrival runway with credit for headwind, dispatch with this higher
ELW is allowed, provided that 1 alternate airport is selected which fully
complies to the dispatch landing requirements. [EU-OPS 1.515]
How this LFLW requirement is developed and how it is applied on other than
dry runways is further explained in the next paragraphs.
2.2.2. Certified Landing Distance
Landing field length performance is developed from flight test demonstrated
landing distances (performed by test pilots).
Flight Test Landing Distance: Demonstrated landing distance on a dry runway,
measured from a height of 50 feet above the landing surface using an aggressive
touchdown technique, maximum manual wheel braking and speed brakes, but
without credit for reverse thrust during the landing ground roll.
Flight test landing techniques used by manufacturers are usually not the same as
techniques used by flight crews in normal airline operations.
The Certified Landing Distance on a dry runway (CLDDRY) is the Flight Test
Demonstrated Landing Distance (FTDLD) plus an additional margin of 67
percent.
CLDDRY = 1.67 x FTDLD
According EU-OPS 1.520 the Certified Landing Distance on a wet runway
(CLDWET) is CLDDRY plus an additional margin of 15%, due to reduced
braking performance.
CLDWET = 1.15 x CLDDRY or 1.92 x FTDLD
Certified Landing Distance on a contaminated (slippery) runway (CLDCNTM)
is the longest of CLDWET and 115% of the required landing distance in
accordance with approved contaminated runway landing distance data [EU-OPS
1.520].
CLDCNTM = CLDWET or 1.15 x LDRCNTM
Certified Landing Distances
Landing Field Limit Weight (LFLW): The maximum weight for which the
Landing Distance Available (LDA) equals the required CLD.
For a dry runway this implies that the planned landing distance for the
LFLWDRY equals (1 / 1.67 =) 60% of the LDA, leaving a 40% planning margin.
For a wet runway this implies that the planned landing distance for the
LFLWWET equals (1 / [1.67x1.15] =) 52% of the LDA, leaving a 48% planning
margin.
LFLW planning margins on LDA
2.2.3. Landing Field Limit Weight – Dry Runway
The LFLWDRY is the maximum weight for which the LDA equals CLDDRY
and therefore requires, under planning conditions, a landing distance from 50
feet above the threshold equal to only 60% LDA.
LFLWDRY requires 60% LDA
This weight does not account for runway slope (if less than 2%), non-standard
temperature and approach speed additives, but this is protected by the margins
used to define the LFLW.
2.2.4. Landing Field Limit Weight – Wet Runway
EU-OPS 1.520An operator shall ensure that when the appropriate weather reports or forec
EU-OPS 1.515 reflects determination of the landing distance on a dry runway.
If, according the weather reports, there is a possibility that at ETA the runway
may be wet, the ELW may not exceed LFLWWET.
LFLWWET is the maximum weight for which the LDA equals CLDWET and
therefore requires, under planning conditions, a landing distance from 50 feet
above the threshold equal to only 52% LDA.
LFLWWET requires 52% LDA
LFLWWET also equals (1/1.15 =) 0.87 LFLWDRY.
LFLWWET = 87% LFLWDRY
2.2.5. Landing Field Limit Weight – Contaminated
(Slippery) Runway
[EU-OPS 1.520] If the planned landing is expected to be made on a
contaminated (slippery) runway, the LFLW shall be the most limiting of:
LFLWWET, and
LFLWCNTM, which is the LFLW based on 115% of the landing distance
determined in accordance with approved contaminated runway data.
Approved contaminated (slippery) runway landing distance data for the B737NG
is available in QRH/PI Normal Configuration Landing Distance. These distances
are already factored by 15%.[PRH B2-1.1.2. Contaminated (slippery) runway
data]
In determining LFLWCNTM with approved contaminated runway data,
regulations do not require the 60% planning margin to be taken into account.
This margin is implemented in the determination of LFLWWET against which
LFLWCNTM has to be checked.
2.3. APPROACH AND LANDING CLIMB
REQUIREMENT - LCLW
Go-Around Requirement
To ensure a minimum climb gradient capability in the certified approach and
landing configuration in case a go-around becomes necessary at any point during
the landing approach, two separate requirements have to be met.
Approach Climb[CS 25.121(d)]
For a two engine airplane the minimum required climb gradient in the approach
configuration (approach flap setting and gear up) with one engine inoperative
and remaining engine at go-around thrust is 2.1%, calculated at a speed not
greater than 1.4 VS1G for the selected approach flap setting.
Landing Climb[CS 25.119]
For a two engine airplane the minimum required climb gradient in the landing
configuration (landing flap setting and gear down) with both engines operating,
where go-around thrust is available 8 seconds after thrust levers are moved from
minimum flight idle to the go-around position, is 3.2%, calculated at a speed not
less than 1.13 VSR or VMCL and not greater than VREF for the selected
approach flaps.
Approach and Landing Climb requirements
For a two engine aircraft, the approach climb requirement is normally more
limiting than the landing climb requirement.
Additional approach climb requirements:
For instrument approaches with a missed approach gradient greater than 2.1%
the approach climb gradient must be at least equal to or greater than the
applicable missed approach gradient.
Published approach minima are normally based on a missed approach gradient
of 2.5%. [IEM-OPS 1.510]
Only for operators subjected to EU-OPS, there is an additional requirement for
Cat II/III approaches:
EU-OPS 1.510For instrument approaches with decision heights below 200 ft, an operator m
Landing Climb Limit Weight (LCLW): The maximum weight which can just
achieve the most limiting of the approach and landing climb requirements which
can be further restricted by the achievability of the required missed approach
gradient.
2.4. QUICK TURNAROUND LIMIT WEIGHT
Besides the LFLW and LCLW, operation can also be limited by the maximum
weight for a quick turnaround (Quick Turnaround Limit Weight – QTLW),
thereby limiting the LDW.
Quick Turnaround Limit Weight (QTLW): The maximum landing weight for
which there is no minimum ground time required with respect to possible fuse
plug melting. This weight does not guarantee sufficient brake energy absorbtion
in case of a subsequent aborted takeoff.
The QTLW protects the wheel fuse plugs from melting during a subsequent
takeoff.
CS-AMC 25.735 The temperature sensitive devices (e.g. fuse or fusible plugs) should be s
The Quick Turnaround Limit Weight restriction only guarantees that fuse plugs
will not melt during the next takeoff and does not provide additional brake
energy protection if it becomes necessary to reject the takeoff.
3. LANDING PERFORMANCE REQUIREMENTS –
INFLIGHT
REQUIRED LANDING DISTANCE AND GO-AROUND GRADIENT
Where dispatch landing requirements result in a Max Allowable LDW, based on
(restrictive) assumed conditions, the inflight requirement consists of
determination of the required landing distance and the achievable go-around
gradient based on the actual LDW under actual conditions.
Inflight landing field and landing climb requirements consist of what is stated in
EU-OPS:
EU-OPS 1.400 Before commencing an approach to land, the commander must satisfy hims
From this it can be concluded that for the actual LDW under the actual landing
circumstances:
LDR must not exceed the LDA.
Required go-around climb gradient must be achieved.
Landing distance data as provided by the manufacturer must be based on worn
brakes.
CS-25.101 The (…) landing distances (…) must be determined with all the aeroplane whee
Regulations do not require margins when determining LDR, but when
determining the LDR when the runway is not dry, a margin of 15% is
recommended.
Normally, pilots are provided with data where this recommendation is
implemented.[PRH B2-2. Inflight (operational) data]
In case of an autoland, an increased landing distance must be taken into account.
CS-AWO 142 [Automatic] Landing distance The landing distance required must be establi
CS-AWO 342 [Automatic] Landing distance If there is any feature of the system or the ass
Your company may require an additional margin.
Additional inflight check:
When dispatched to a destination having a single runway and the ELW exceeds
the LFLW, which has been determined for the most favorable runway without
credit for headwind, an inflight check must determine that the actual LDW does
not exceed the LFLW calculated for actual wind.
INTRODUCTION PERFORMANCE DATA Performance Data of the 737NG is made ava
1. TL-CHARTS
WEIGHTS AND ADJUSTMENTS
1.1. GENERAL
A Takeoff Limiting (TL) - chart is:
also referred to as Runway -, Airport - or Takeoff Analysis.
an efficient and accurate means for determining Max Allowable TOW and
assumed temperature for reduced thrust.
a printed result of runway-specific takeoff performance information for a
specific aircraft configuration, generated using computer software (Boeing
AFM-DPI). PLTOW’s (and sometimes together with corresponding takeoff
speeds) for a range of temperatures and wind components are presented.
Boeing computer software can produce TL-charts in several formats, but,
regarding the PLTOW, normally displays:
Brake Release Limit Weights (BRLW) as a function of OAT and wind
component.
The most limiting value of Field Length Limit, Obstacle, Tire Speed and Brake
Energy Limit TOW is displayed, normally provided with a Limit Code
corresponding to the most limiting takeoff requirement.
The wind requirement of 50% HWC / 150% TWC is implemented.
Climb Limit Takeoff Weights (CLTOW) as a function of OAT.
Certified for no-wind condition so independent of wind component.
Constant (or almost constant) below FRT and decreases with increasing OAT
(decreasing thrust).
It also displays:
Airplane configuration (eg. winglet / flap setting), engine rating (eg. 27K), and
applicable airport data (eg. field elevation).
Engine failure procedure (Emergency Turn), if applicable.
Weight adjustment values for non-standard QNH.
Runway characteristics and obstacle data.
Possible Layout TL-chart
1.2. WEIGHT ADJUSTMENTS
Besides the OAT and wind component, weights on a standard TL-chart are based
on:
what is stated in the header, regarding runway condition and anti-ice and
airco/press system setting.
standard pressure (1013 hPa / 29.92” Hg).
all equipment operating at the start of takeoff.
Any deviation from standard pressure, equipment serviceability and what is
stated in the TL-chart header (i.e. what TL-data are based on) needs to be
corrected for.
Both BRLW and CLTOW are influenced by situations affecting the available
thrust:
Ambient pressure, as a function of the air density.
Engine bleed demand
is increased by switching Anti Ice and Airco/Press systems ON, thereby
decreasing available thrust.
can be diminished by using APU as bleed source.
Only BRLW (and NOT the CLTOW) is influenced by the runway condition,
since this is the limit weight while the aircraft is still in contact with the runway.
1.2.1. Corrections on both BRLW and CLTOW
1.2.1.1. QNH Correction
TL-chart weights are based on the standard pressure of 1013 hPa (29.92” Hg).
If the actual QNH is not standard, the available thrust is different from what the
TL-weights are calculated with.
QNH < 1013 hPa (29.92” Hg): BRLW and CLTOW must be decreased.
QNH > 1013 hPa (29.92” Hg): BRLW and CLTOW may be increased.
The amount of correction (given in kg/hPa) is normally displayed on the TLtable in the same column (or row) from which the BRLW and CLTOW are taken.
1.2.1.2. Anti-Ice Correction
If the Wing Anti-Ice (WAI) or Engine Anti-Ice (EAI) system is switched ON,
bleed air is taken from the engine, resulting in less available thrust, thereby
affecting BRLW and CLTOW.
EAI has to be switched ON any time icing conditions exist or are expected
during takeoff.
ICING CONDITIONS Icing conditions exist when OAT (on the ground) or TAT (inflight)
WAI shall be switched ON any time the EAI is switched ON except when the
aircraft is, or will be, treated with type II or IV de-icing fluid according an
approved ground de-icing program. Fluid-viscosity is affected by the heat of the
WAI, decreasing the effectiveness of the de-icing fluid.
B737: WAI is automatically switched OFF when advancing the Thrust Levers
for takeoff.
If TL-weights are based on Anti-Ice OFF, and the use of EAI and/or WAI is
anticipated during takeoff up to 1500 feet, BRLW and CLTOW need to be
corrected.
A WAI penalty might not be applicable because it is not intended to be used
immediately after liftoff. Since WAI is primarily a DE-ice system, icing
conditions would be severe if WAI is needed during takeoff. When this is
anticipated, the takeoff should be delayed since flying into known severe icing is
prohibited.
1.2.1.3. Engine Bleed Correction
When the engine bleeds are switched ON, bleed air is taken from the engines to
supply the airconditioning/pressurization system, resulting in less available
thrust.
If TL-chart weights are based on Engine Bleeds OFF (indicated as “AIRCOND
OFF”), and it is switched ON during takeoff, BRLW and CLTOW need to be
corrected.
Engine Bleed penalty may be avoided by using the APU as the bleed source.
1.2.1.4. Unserviceable Equipment
MEL 73-11 allows dispatch with both Electronic Engine Control (EEC) in the
Alternate Mode.
With EEC in ALTN mode:
TL-chart weights are not valid anymore and need to be adjusted.
FCOM/PI offers a simplified and conservative method by reducing the PLTOW.
1.2.2. Additional Corrections on BRLW only
1.2.2.1. Runway Surface Condition
If, due to the runway not being dry, acceleration and/or deceleration are affected,
the BRLW has to be lower than in the dry runway situation. [PRH A1-2.2.4.2.
Rebalancing]
A weight correction on BRLW is needed any time the actual runway condition
does not match the runway condition the TL-chart is based on.
Weight penalties are available in the FCOM, where the dry-weight serves as an
input.
TL-charts based on a specific runway condition (e.g. wet) may be available.
1.2.2.1.1. Wet runway weight correction
A TL-chart based on wet runway performance (WET TL-chart) may be
available.
The BRLW taken from a WET TL-chart (BRLWWET) already reflects the
reduced weight to account for the reduced stopping capability, but still needs to
be corrected for non-standard QNH, anti-ice etc.
If no WET TL-chart is available, the BRLWWET has to be determined from a
standard (DRY) TL-chart by reducing the BRLWDRY with a wet runway weight
adjustment.
BRLWWET = BRLWDRY + wet runway weight adjustment (negative value)
Weight adjustment values from the FCOM/PI SLIPPERY RUNWAY –
REPORTED BRAKING ACTION GOOD table may serve as wet runway
weight adjustment.
This is only valid when no credit for clearway is accounted for in determining
BRLWDRY, since this is not allowed on a wet runway.
Using FCOM/PI data to determine Wet runway weight adjustment
1.2.2.1.2. Contaminated runway weight correction
Determination of the Brake Release Limit Weight on a contaminated runway
(BRLWCNTM) is based on application of a weight penalty on BRLWDRY.
BRLWCNTM = BRLWDRY + contaminated rwy weight adjustment (negative
value)
The applicable weight adjustment values depend on the contaminant type, which
is either fluid (like standing water, slush or snow) [PRH A1-2.2.5.3.1. Fluid
Contaminants] or hard (like compacted snow or ice) [PRH A1-2.2.5.3.2. Hard
Contaminants].
Since fluid contaminants affect both acceleration and deceleration, the
corresponding weight penalties are higher than those with respect to hard
contaminants, which only affect deceleration.
Regarding runways contaminated with a fluid type contaminant, weight penalties
can be found in FCOM/PI SLUSH/STANDING WATER TAKEOFF – WEIGHT
ADJUSTMENT table.
Using FCOM/PI data to determine weight adjustment on fluid contaminant
covered runway
SLUSH/STANDING WATER TAKEOFF table(FCOM/PI) Data assumes: - screen height a
Regarding runways contaminated with a hard type contaminant, weight penalties
can be found in FCOM/PI SLIPPERY RUNWAY TAKEOFF – WEIGHT
ADJUSTMENT table.
Using FCOM/PI data to determine weight adjustment on hard contaminant
covered runway
SLIPPERY RUNWAY TAKEOFF table(FCOM/PI) Data assumes: - screen height above th
1.2.2.2. Unserviceable Equipment
TL-chart weights are based on all equipment operating at the start of the takeoff.
Unservicability of the following systems affect the BRLW:
Antiskid Unserviceability of the Antiskid system is allowed on a dry runway, but prohibite
Thrust Reverser Since on a dry runway the ASD is not credited for reverse thrust, there is n
1.3. V1 ADJUSTMENT – Actual TOW
V-speeds have to be obtained from the QRH or FMC for the actual TOW.
V1 obtained from the FMC or QRH is the Balanced V1 and needs to be adjusted
in case:
clearway and stopway are not equal. [PRH A1-2.2.4.2. Rebalancing]
acceleration or deceleration capability is affected [PRH A1-2.2.4.1.2. Required
unbalancing], due to:
runway slope
headwind or tailwind
runway surface condition
unserviceable equipment
1.3.1. Clearway and Stopway Correction
From the runway information on the bottom of the TL-chart, the clearway can be
determined as TODA minus TORA and the stopway as ASDA minus TORA.
Clearway = TODA - TORA
Stopway = ASDA - TORA
Clearway minus Stopway = TODA - ASDA
If clearway and stopway are not equal, the presented TL-chart weights are based
on this unbalanced situation and therefore FMC/FCOM V1 needs to be
adjusted [PRH A1-2.2.4.1.2. Required unbalancing].
Clearway minus Stopway > 0: V1 decrease
Clearway minus Stopway < 0: V1 increase
The amount of V1-adjustment is a function of the difference between clearway
and stopway and can be found in the FCOM/PI CLEARWAY AND STOPWAY
V1 ADJUSTMENT table.
Using FCOM/PI data to determine V1 adjustment in case clearway and stopway
are not equal
Since on a wet runway no credit for clearway is allowed, the value of clearway
minus stopway is either zero (situation without stopway) or a negative value
(situation with stopway).
Regulations limit the clearway length which may be taken into account to half
the takeoff flare distance [PRH A1-2.2.2.1. Clearway]. These values are
displayed in the FCOM/PI MAXIMUM ALLOWABLE CLEARWAY table.
Normally, pilots are provided with data which already takes the maximum
allowable clearway into account.
1.3.2. Slope and Wind
A runway upslope or headwind component affect the acceleration – a higher V1
is needed.
Upslope / Headwind: V1 increase
A runway downslope or tailwind component affect the deceleration – a lower V1
is needed.
Downslope / Tailwind: V1 decrease
The value that V1 needs to be corrected for, is available in the FCOM/PI SLOPE
AND WIND V1 ADJUSTMENTS table.
Normally a single (average) value of runway slope is available where the actual
slope may vary along the runway. A non-lineair runway slope may have an
adverse effect on aircraft acceleration or deceleration, not reflected in the
performance calculations.
1.3.3. Runway surface condition
FMC/FCOM V1 are available for a dry and wet runway.
Due to the degraded deceleration capability on a wet runway (acceleration is
unaffected), V1WET is lower than V1DRY. [PRH A1-2.2.5.2. Wet runway]
If the runway is contaminated, the V1CNTM has to be obtained by adjusting
V1DRY.
V1CNTM = V1DRY + correction
The amount of V1 correction depends on the contaminant type, which is either
fluid (like standing water, slush or snow) [PRH A1-2.2.5.3.1. Fluid
Contaminants] or hard (like compacted snow or ice) [PRH A1-2.2.5.3.2. Hard
Contaminants].
On a runway contaminated with a fluid contaminant the aircrafts ability to both
accelerate and decelerate is degraded [PRH A1-2.2.5.3.1. Fluid Contaminants].
Since the deceleration is affected more significantly than the acceleration, V1
needs to be lowered. But with increasing contaminant depth, acceleration will
become increasingly affected, resulting in a less negative adjustment value on
V1DRY. Corresponding adjustments can be found in FCOM/PI
SLUSH/STANDING WATER TAKEOFF – V1 ADJUSTMENT table.
Using FCOM/PI data to determine V1 adjustment in case of fluid contaminant
covered runway
On a runway contaminated with a hard contaminant, acceleration is unaffected.
Due to degraded tire-to-ground friction, the deceleration capability is degraded
and lowering V1 is needed [PRH A1-2.2.5.3.2. Hard Contaminants].
Corresponding adjustments can be found in FCOM/PI SLIPPERY RUNWAY
TAKEOFF – V1 ADJUSTMENT table.
Using FCOM/PI data to determine V1 adjustment in case of hard contaminant
covered runway
In case the adjusted V1 becomes lower than VMCG it has to be set equal to
VMCG.
For a given available runway length (ASDA), there will be a limit weight for
which V1 is equal to VMCG without risking a RTO overrun: V1MCG Limit
Weight. FCOM/PI provides V1MCG limit weights for both slippery and
slush/standing water takeoffs, and it must be checked if this weight is not
exceeded [PRH A1-2.2.5.3.4. V1MCG Limit Weight].
1.3.4. Unserviceable Equipment
Unserviceabilty of equipment that affects the aircrafts ability to accelerate or
decelarate requires a V1 adjustment [PRH A1-2.2.4.2. Rebalancing].
1.3.4.1. Deceleration affected
Unserviceability of the following systems affect deceleration requiring a lower
V1:
Antiskid Unserviceability of the antiskid system is allowed on a dry runway, but prohibited
1.3.4.2. Acceleration affected
Unservicability of the following system affects acceleration, requiring a higher
V1:
EEC in ALTN mode With EEC in ALTN mode, acceleration is affected, requiring a higher
2. NO TL-CHART AVAILABLE
LIMIT WEIGHTS FROM FCOM/PD
TL tables become invalid in case of changes in specified takeoff runway length
or changes in obstacle situations.
In case no valid or updated TL-chart is available, the limiting Takeoff Weights in
accordance with the takeoff performance requirements must be seperately
determined. The most limiting TOW determines the PLTOW and must be
checked against the structural TOW to find the Max Allowable TOW [Overview
Max Allowable TOW].
In the FCOM/PD tables, Boeing provides conservative data to determine the
Field length, Climb and Obstacle Limit Takeoff Weights. Tirespeed Limit
Weights can also be found in the FCOM/PD together with the Max Brake
Energy Speeds. When these data are not provided, the Tirespeed and Brake
Energy are not limiting for the range of conditions shown (eg. B737-700 data).
2.1. FIELD LIMIT TAKEOFF WEIGHT
The FCOM/PD presents tabular data to determine the Field Limit TOW.
Data are available for Flaps 5 covering a range of pressure altitudes for both a
dry and wet runway and are valid for engine bleeds ON and anti-ice OFF.
Corrections on the available field length with respect to slope and wind are also
presented.
Regarding the wind correction data, the requirement to account for 50% of the
HWC and 150% of the TWC is implemented.
When the aircraft cannot be positioned at the threshold, the line-up
correction [PRH A1-2.2.3. Lineup corrections] must be applied and correction
values can be found in the text-section of the FCOM/PD. The highest presented
value (which is the ASDA-correction) must be used.
2.2. CLIMB LIMIT TAKEOFF WEIGHT
The Climb Limit TOW can be obtained from the same FCOM/PD table as from
which the Field Limit TOW is determined.
Data are available for Flaps 5 covering a range of Pressure Altitudes and OAT’s
and are valid for engine bleeds ON and anti-ice OFF.
Using FCOM/PD data to determine (Dry/Wet) Field and Climb LW
Normally a single (average) value of runway slope is available where the actual
slope may vary along the runway. A non-lineair runway slope may have an
adverse effect on aircraft acceleration or deceleration, not reflected in the
performance calculations.
2.3. OBSTACLE LIMIT WEIGHT
Obstacle Limit TOW data are presented for flaps 5, engine bleeds ON and antiice OFF.
Data is also available to make adjustments for OAT, PA and wind.
In order to use this table, obstacle data, regarding height and distance from the
brake release point, must be available.
Obstacle data information may be given with reference to end of TORA.
When applying line-up corrections, the obstacle distance from brake release
must be reduced by the ASDA adjustment.
Obstacle height must be calculated from lowest point of the runway to
conservatively account for runway slope.
Using FCOM/PD data to determine Obstacle LW
2.4. TIRE SPEED LIMIT WEIGHT
These data are only provided if it might restrict the TOW for the conditions
shown.
The Tire Speed Limit Weight is shown as a function of OAT and PA, and is valid
for a flaps 5 takeoff under no wind conditions.
Wind correction values are provided at the bottom of the table.
Data are based on the certified tire speed limit of 225 mph (195 kts).
Using FCOM/PD data to determine Tire Speed LW
2.5. BRAKE ENERGY LIMIT
FCOM/PD provides data to determine the Maximum Brake Energy speed as a
function of OAT, PA and Weight, only if it might restrict the takeoff for the
conditions shown.
These data are valid for a takeoff in zero wind on a level runway, therefore need
to be adjusted for wind and/or runway slope. Correction values are presented at
the bottom of the table:
Uphill slope or headwind help the stopping capability, allowing a higher VMBE.
Downhill slope or tailwind hurt the stopping capability, requiring a lower
VMBE.
The determined Maximum Brake Energy Speed (VMBE) is the upper-limit for
V1.
Using FCOM/PD data to determine VMBE
1. DISPATCH DATA
CERTIFIED DATA TO DETERMINE MAX ALLOWABLE LANDING
WEIGHT
The Maximum Allowable LDW is determined from the most limiting of the
Sructural LDW and the Performance Limit LDW, which in turn is the lowest of
the Landing Field Limit Weight and Landing Climb Limit Weight.
Regulations also require a LDW check to assure the aircraft is able to achieve
the minimum required go-around climb gradient.
Besides regulatory restrictions, the Maximum Allowable LDW can also be
limited by operational restrictions regarding a quick turnaround.
1.1. LANDING FIELD LIMIT WEIGHT
1.1.1. Dry and Wet Runway
FCOM/PD provides data to determine the Landing Field Limit Weight for both
dry and wet runways, either in separate or combined tables.
These data already meet the following requirements:
60% of the available landing distance has been taken into account.
50% of the HWC and 150% of the TWC is considered.
As a dispatch requirement [PRH A3-2.2. Landing field requirement], LFLW is
the lowest of the LFLW determined for:
the most favorable runway without wind, and
the expected landing runway with wind.
Presented data are valid for flaps 40, and are based on antiskid operative and
automatic speedbrakes, representing the best achievable landing perfomance
regarding required field length.
In case the landing will be performed with manual selection of the speedbrakes
(when the auto speedbrake system is inop), a weight penalty is provided at the
bottom of the table.
Separate tables are available in case both the antiskid and auto speedbrake
systems are inoperative.
Using FCOM/PD data to determine LFLWDRY or LFLWWET
1.1.2. Contaminated (Slippery) Runway
Landing Field Limit Weight for a planned landing on a contaminated (slippery)
runway is the lesser of LFLWWET and the LFLW based on the required landing
distance according to approved contaminated runway data (LFLWCNTM). [PRH
A3-2.2.5. LFLW contaminated (slippery) rwy]
Approved contaminated runway data can be found as advisory information in the
QRH/PI Landing Distance tables with reported braking action. Normally this
table has to be applied when determining the required landing distance with the
actual LDW inflight, but can, during dispatch, also be used in reverse to
determine the LFLWCNTM based on the LDA.
Method to obtain the LFLWCNTM from QRH/PI Landing Distance data:
Obtain Reference Weight from the 1st column (REF DIST) of this table.
Determine LDR of the Reference Weight (LDRREF) by adjusting REF DIST as
applicable for ALT, WIND, SLOPE, VREF and TEMP.
Use weight adjustment data from 2nd column (WT ADJ) to convert the difference
between LDRREF and LDA into a weight adjustment.
If LDRREF < LDA add this weight adjustment to the Reference Weight.
If LDRREF > LDA substract this weight adjustment from the Reference Weight.
When using approved contaminated runway data, regulations do require an
additional planning margin of 15% to be taken into account. In the Normal
Configuration Landing Distance data for braking action Good, Medium and Poor
this margin of 15% is already implemented (factored data).
Using QRH/PI data in reverse to determine LFLWCNTM
1.2. LANDING CLIMB LIMIT WEIGHT
FCOM/PD provides data to determine the Landing Climb Limit Weight.
Per OAT and PA only the most limiting (lowest) value of Approach Climb and
Landing Climb Limit Weight is given, therefore this table is valid for approach
with flaps 15 and landing with flaps 40.
Presented data are based on engine bleed for packs ON and anti-ice OFF,
therefore a weight correction is needed in case the configuration is different.
Besides weight correction values for anti-ice and packs, at the bottom of the
table a correction is also available to account for possible ice built-up on
unheated surfaces (eg. outboard LE devices).
Using FCOM/PD data to determine LCLW
1.3. GO-AROUND CLIMB GRADIENT
FCOM/PD provides data to determine if an aircraft with the planned (or inflight
the actual) LDW will be able to achieve the required go-around climb gradient.
These data assume a go-around in the worst case configuration: one engine
inoperative with flaps still at 15 (e.g. as a result of an engine failure in a dual
engine go-around).
This table can also be used in reverse by using the required missed approach
climb gradient as input to determine the LCLW which is able to achieve this.
Using FCOM/PD data to determine N-1 Go-Around Gradient
1.4. QUICK TURNAROUND LIMIT WEIGHT
The Quick Turnaround Limit Weight table in the FCOM/PD shows the
maximum landing weight for which there is no mandatory minimum ground
time for brake cooling prior to the next departure, given for only 1 flap setting
(flaps 40).
Presented data is valid for a level runway in no wind, and corrections are
available to account for up- or downslope and head- or tailwind.
If the Actual Landing Weight exceeds the Quick Turnaround Limit Weight from
the table, a mandatory minimum ground time (B737: 67 minutes) must be
observed to protect against melting of the wheel fuse plug and loss of tire
pressure during the next takeoff.
As a certification requirement, Quick Turnaround Limit Weight is conservatively
based on maximum manual wheel braking with no credit for reverse thrust.
The Quick Turnaround Limit Weight restriction only guarantees that fuse plugs
will not melt during the next takeoff and does not provide additional brake
energy protection if it becomes necessary to reject the takeoff.
Using FCOM/PD data to determine Quick Turnaround Limit Weight
2. INFLIGHT (OPERATIONAL) DATA
ADVISORY LANDING DISTANCE AND BRAKE COOLING INFORMATION
QRH/PI presents advisory information to determine:
required landing distance in both normal and non-normal situations
recommended brake cooling schedule.
Due to the high cost of certifying the advisory information, this advisory
information is accepted performance in EASA certification. Therefore EASA
operators must use this Advisory Information as mandatory performance.
2.1. LANDING DISTANCE REQUIRED
To check if the available landing distance is sufficient for the landing distance
required by the actual landing weight under the actual conditions, landing
distance data from the QRH/PI have to be applied.
Following data is available to determine required landing distance:
Normal Configuration Landing Distance
Non-normal Configuration Landing Distance
The QRH/PI Landing Distance data assume the following:
QRH/PI Landing distance data assumptions
2.1.1. Normal Configuration Landing Distance
Data available for both certified landing flap settings: 30 & 40.
Regarding runway condition, data is provided for a dry runway and for runways
with reported braking action GOOD, MEDIUM and POOR.
Distances for a dry runway are actual (unfactored) distances, and distances for
reported braking actions GOOD, MEDIUM and POOR are factored with 15%.
Distance from 50 feet over the threshold to the touchdown point are included,
where touchdown is assumed to take place 1000ft (305m) beyond the threshold
with a touchdown speed of approximately 98% of the threshold speed.
Data is presented as a function of the braking configuration: MAX MANUAL
and Autobrake settings 1, 2, 3 and MAX.
AUTOBRAKE SETTING
SCHEDULED DECELERATION RATE
1
4 ft/sec²
2
5 ft/sec²
3
7 ft/sec²
MAX
14 ft/sec² (>80kts) 12 ft/sec² (<80kts)
Note: The limit value to achieve the MAX rate is less
than full hydraulic system pressure. Manually
applying maximum pedal pressure to achieve
maximum hydraulic pressure to the brakes will result
in a higher deceleration rate and a shorter stopping
distance than MAX.
As runway friction deteriorates, it is less likely that the airplane will achieve the
scheduled autobrake deceleration rates in which case the actual runway stopping
distance will be determined by the runway friction capability.[PRH C2-2.3.2.
Reverse vs. brakes]
Max manual braking achieves the best performance since it combines maximum
reverse thrust with maximum footbrake, where the autobrake modulates the
wheel brakes as a function of the amount of reverse thrust to keep the scheduled
deceleration rate.
Max manual braking data assume the use of auto speedbrake. Max manual
braking in combination with manual speedbrakes requires a distance correction
(penalty).
Autobrake data is valid for both manual and auto speedbrake.
Reference distance is valid for a reference weight at SL, standard day with no
slope or wind and 2 engine detent (no.2) reverse thrust (initiated within 2
seconds after touchdown and 1 second after brake application).
The following adjustments have to be made in cases where the actual situation
differs from the assumed conditions:
WEIGHT – a weight other than the reference weight has to be corrected for.
ALTITUDE – correction if airports PA is above SL.
WIND – head wind (tailwind) results in decreased (increased) LDR.
SLOPE – uphill (downhill) slope results in decreased (increased) LDR.
TEMPERATURE – deviations from ISA (at actual PA) requires correction.
VREF – distances assume VREF (for the given flap setting) over the threshold.
REVERSE THRUST – correction required if one or both T/Rs are not being used.
TOUCHDOWN POINT – The 1000ft touchdown point is provided as a reference
and needs to be adjusted as required.
The aiming point marking on the runway is not always positioned at 1000 feet
(305 meters) from the threshold, so when aiming for these markings, the actual
touchdown point might be more than 1000 feet (305 meters) from the threshold,
thereby increasing the actual landing distance.
When landing at the end of the aiming point marking, the actual landing
distance might be up to 500 feet (150 meters) longer than the operational
landing data assume.[PRH C2-2.2.2. Aiming point marking]
2.1.2. Non-Normal Configuration Landing Distance
Distances are published for a dry runway and for runways with reported braking
action GOOD, MEDIUM and POOR.
Distances are all actual (unfactored) distances and assume MAX MANUAL
braking.
Data is presented as a function of the (non-normal) configuration.
Reference distance assumes a level runway at SL, standard day with no wind and
correction values are presented if the actual situation is different.
Regarding VREF adjustment: it is assumed that the reference speed required by
the (non-normal) configuration (eg. an all flaps up landing requires a reference
speed of VREF,40 + 55 kts) is flown over the threshold.
Using QRH/PI data to determine LDR
2.2. RECOMMENDED BRAKE COOLING
SCHEDULE
Recommended Brake Cooling Schedule provides brake energy protection if it
becomes necessary to reject the takeoff.
Recommended Brake Cooling Schedule provides the only means of evaluating
brake cooling requirements following repeated landings at short time intervals or
a rejected takeoff.
Data is given as a function of:
Weight
OAT / PA
Brakes on speed
Reverse thrust use (both or none)
Braking configuration (MAX MANUAL and Autobrake settings 1, 2, 3 and
MAX)
Adjustment is available for additional taxi distance.
Interpolation is made a lot easier when groundspeed is used for brakes on speed,
in which case the wind may be ignored and the table may be entered with SL and
15°C (59°F).
Using QRH/PI data to determine recommended brake cooling time
1. PERFORMANCE RULE DETERMINATION
WHICH DATA TO APPLY
In order to find out which performance rules apply to the actual takeoff situation:
determine the runway conditions using the Runway State Message in the
METAR or SNOWTAM in the NOTAMS, whichever is available, and
use the outcome to enter the table below, from left to right.
This will lead you to the chapter which describes the applicable performance
rules.
RUNWAY COVERAGE
CONTAMINANT
WATER EQU
[not relevant]
None
[not relevant]
>Any
WET
Damp
<= 25%
> 25%
Water, Slush or (Dry/Wet) Snow
Any
CONTAMINATED-HARD
>= 3mm (2)(3) and <= 13mm
[not relevant]
> 13mm (0.5")
NOT RECOMMENDED(4)
Comp.Snow / Ice
[not relevant]
< 3mm (0.125
CONTAMINA
As a guideline, the Water Equivelent Depth (WED) can be determined from the
table below:
MEASURED CONTAMINANT DEPTH
WATER EQUIVALENT DEPTH
Standing water / Slush / Wet snow
Dry (Loose) Snow
3mm (0.125")
12mm (0.5")
6mm (0.25")
24mm (1.0")
9mm (0.375")
36mm (1.5")
13mm (0.5")
50mm (2.0")
Although according the EU-OPS definition [PRH A1-2.2.5.3. Contaminated
runway] a runway (> 25%) covered with a fluid contaminant of exactly 3mm
(0.125”) deep is not considered contaminated, it is recommended to classify it as
such, since Boeing provides slush/standing water data for depths including 3mm
(0.125”).
Takeoff in slush depth > 6mm (0.25”) is not recommended at altitudes greater
than 8000 feet.
Takeoff in slush depth > 13mm (0.5”) is not recommended due to possible
airplane damage (also no data available).
SNOWTAM (NOTAM) SNOWTAM: A specialized NOTAM notifying the presence of haz
RUNWAY STATE MESSAGE (METAR) Runway State Message: Information on runway
2. DRY RUNWAY
EU-OPS 1.480A dry runway is one which is neither wet nor contaminated, and includes th
EU-OPS 1.475For performance purposes, a damp runway, other than a grass runway, may
EU-OPS 1.480A runway is considered damp when the surface is not dry, but when the mo
A damp or a wet grooved/PFC runway may not yield the same level of
performance as on a dry runway.
2.1. MAXIMUM ALLOWABLE TOW
Use OAT and Wind component to find BRLW and CLTOW on the TL chart of
the intended takeoff runway/intersection.
Apply (substract) weight corrections – AI / Eng Bleed / QNH (if < 1013, else
add) – as applicable to find BRLWDRY and (corrected) CLTOW. [PRH B1-1.2.
Weight adjustments]
Use most limiting as PLTOW and check this against (Certified) Structural TOW.
Use the lowest as Max Allowable TOW.
2.2. ASSUMED TEMPERATURE REDUCED
THRUST
Use Actual TOW and apply (add) weight corrections – AI / Eng Bleed / QNH
(if < 1013, else substract – take highest value corresponding to BRLW and
CLW) – as applicable, to find Actual Performance TOW.
Use TL chart of intended takeoff runway/intersection to find the highest OAT
for which both the associated BRLW and CLTOW exceeds the Actual
Performance TOW, where a TWC must be taken into account, and a HWC may
be taken into account.
Use this OAT as Assumed Temperature to enter in the FMC.
An Assumed Temperature less than the engine’s Flat Rated Temperature [ISA +
15°C (27°F)](1)will not result in a thrust reduction and will show an ‘INVALID
ENTRY’ alert in the scratchpad of the CDU.
(1)The FRT is given as Minimum Assumed Temp in FCOM/PI ASSUMED
TEMPERATURE REDUCED THRUST.
2.3. V SPEEDS
2.3.1. Using FCOM
2.3.2. Using FMC
With actual ZFW and PLANNED TOF entered on PERF REF-page of the FMC,
TAKEOFF REF-page 1/2 shows correct VR and V2 speeds.
With FMC/TAKEOFF REF-page 2/2 filled out correctly with actual wind and
runway slope, TAKEOFF REF-page 1/2 shows balanced V1 corrected for
VMCG.
The FMC computed V1 may be lower than the value of VMCG from FCOM/PI.
This is because the FMC V1 is based on calculation of VMCG with the actual
TOW, where the FCOM/PI value is based on a (conservative) low TOW
(requiring a high VMCG). No VMCG correction is needed for the FMC
computed V1.
Normally a single value of (average) runway slope is available where the actual
slope may vary along the runway. A non-lineair runway slope may have an
adverse effect on aircraft acceleration or deceleration, not reflected in the
performance calculations.
If TL chart weights are based on unequal TODA and ASDA (i.e. clearway ≠
stopway), displayed (balanced) V1 on TAKEOFF REF-page 1/2 needs to be
adjusted as a function of CLEARWAY MINUS STOPWAY [PRH A1-2.2.4.1.2.
Required unbalancing], using CLEARWAY AND STOPWAY V1
ADJUSTMENTS table in the FCOM/PI.
If V1 is manually lowered it must be checked against VMCG from FCOM/PI
V1(MCG) table. Use the higher as V1.
3. WET RUNWAY
EU-OPS 1.480 A runway is considered wet, when the runway surface is covered with wate
3.1. USING WET TL CHART
3.1.1. Maximum Allowable TOW
Use OAT and Wind component to find BRLW and CLTOW on the (WET) TL
chart of the intended takeoff runway/intersection.
Apply (substract) weight corrections – AI / Eng Bleed / QNH (if < 1013, else
add) – as applicable to find BRLWWET and (corrected) CLTOW.
Use most limiting (lowest) of BRLWWET and (corrected) CLTOW as and
check this against (Certified) Structural TOW.
Use the lowest as Maximum Allowable TOW.
3.1.2. Assumed Temperature Reduced Thrust
Use Actual TOW and apply (add) weight corrections – AI / Eng Bleed / QNH
(if < 1013, else substract – take highest value corresponding to BRLW and
CLW) – as applicable, to find Actual Performance TOW.
Use (WET) TL chart of intended takeoff runway/intersection to find the highest
OAT for which both the associated BRLW and CLTOW exceeds the Actual
Performance TOW, where an existing TWC must and an existing HWC may be
taken into account.
Use this OAT as Assumed Temperature to enter in the FMC.
An Assumed Temperature less than the engine’s Flat Rated Temperature [ISA +
15°C (27°F)](1)will not result in a thrust reduction and will show an ‘INVALID
ENTRY’ alert in the scratchpad of the CDU.
(1)The FRT is given as Minimum Assumed Temp in FCOM/PI ASSUMED
TEMPERATURE REDUCED THRUST.
3.2. USING DRY TL CHART
3.2.1. Maximum Allowable TOW
Use OAT and Wind component to find BRLW and CLTOW on the normal
(DRY) TL chart of the intended takeoff runway/intersection.
Apply (substract) weight corrections – AI / Eng Bleed / QNH (if < 1013, else
add) – as applicable to find BRLWDRY and (corrected) CLTOW.
Use BRLWDRY (which can be taken for DRY/FIELD OBSTACLE LIMIT
WEIGHT) as input for FCOM/PI SLIPPERY RUNWAY TAKEOFF – WEIGHT
ADJUSTMENT – REPORTED BRAKING ACTION GOOD table, with the
applicable PA, to find the Weight Adjustment value the BRLWDRY needs to be
corrected with to find BRLWWET.
This is only valid when no credit for clearway is taken into account in
determining BRLWDRY, since this is not allowed on a wet runway.
Determine V1(MCG) Limit Weight from FCOM/PI SLIPPERY RUNWAY
TAKEOFF – V1(MCG) LIMIT WEIGHT – REPORTED BRAKING ACTION
GOOD table, using ASDA and PA as input.
Use the most limiting (lowest) of (corrected) CLTOW, BRLWWET and
V1(MCG)LW as the PLTOW and check this against the (Certified) Structural
TOW to find the Maximum Allowable TOW.
3.2.2. Assumed Temperature Reduced Thrust
Use Actual TOW and apply (add) weight corrections – AI / Eng Bleed / QNH
(if < 1013) – as applicable, to find Actual Performance CLIMB TOW.
Use Actual TOW and apply (add) weight corrections (as applicable) for AI,
Eng Bleed, QNH (if < 1013, else substract) and Wet Runway Weight Penalty, to
find Actual Performance BRAKE RELEASE TOW, where the Wet Runway
Weight Penalty is the highest value from the FCOM/PI SLIPPERY RUNWAY
TAKEOFF – WEIGHT ADJUSTMENT – REPORTED BRAKING ACTION
GOOD table for the actual PA.
Use TL chart of intended takeoff runway/intersection to find the highest OAT
for which the associated CLTOW exceeds the Actual Performance CLIMB TOW
and the associated BRLW exceeds the Actual Performance BRAKE RELEASE
TOW, where an existing TWC shall be, and an existing HWC may be taken into
account.
Use this OAT as Assumed Temperature to enter in the FMC.
An Assumed Temperature less than the engine’s Flat Rated Temperature [ISA +
15°C (27°F)](1)will not result in a thrust reduction and will show an ‘INVALID
ENTRY’ alert in the scratchpad of the CDU.
(1)The FRT is given as Minimum Assumed Temp in FCOM/PI ASSUMED
TEMPERATURE REDUCED THRUST.
3.3. V SPEEDS
3.3.1. Using FCOM
3.3.2. Using FMC
With actual ZFW and PLANNED TOF entered on PERF REF-page of the FMC,
TAKEOFF REF-page 1/2 shows correct VR and V2 speeds.
If FMC/TAKEOFF REF-page 2/2 is filled out correctly with actual wind and
runway slope, and RWY COND “WET” is highlighted, TAKEOFF REF-page
1/2 shows balanced V1WET corrected for VMCG.
The FMC computed V1 may be lower than the value of VMCG from FCOM/PI.
This is because the FMC V1 is based on calculation of VMCG with the actual
TOW, where the FCOM/PI value is based on a (conservative) low TOW
(requiring a high VMCG). No VMCG correction is needed for the FMC
computed V1.
Normally a single value of (average) runway slope is available where the actual
slope may vary along the runway. A non-lineair runway slope may have an
adverse effect on aircraft acceleration or deceleration, not reflected in the
performance calculations.
If TL chart weights are based on a stopway (regulations do not allow a clearway
to be taken into account on a wet runway), displayed (balanced) V1WET on
FMC/TAKEOFF REF-page 1/2 needs to be adjusted [PRH A1-2.2.4.1.2.
Required unbalancing] as a function of CLEARWAY MINUS STOPWAY, using
CLEARWAY AND STOPWAY V1 ADJUSTMENTS table in the FCOM/PI
(This can only result in a higher V1, since only stopway may be taken into
account).
FMC speeds can be verified with the tables in the FCOM/PI.
On TAKEOFF REF page 2/2 of the FMC also RWY COND “WET SK-R” can
be selected, accessing takeoff performance on wet-skid resistant surfaces such as
grooved runways and porous friction course (PFC) runways. These data reflect
70% of dry runway performance.
These WET SK-R data may only be used if the runway is constructed and
maintained to meet the Friction Level Classification for Runway Pavement
Surface. Operational approval of the wet skid resistant data must be obtained
from the appropriate regulatory authority.
4. CONTAMINATED RUNWAY
FLUID OR HARD CONTAMINANT
4.1. GENERAL
EU-OPS 1.480 A runway is considered to be contaminated, when more than 25% of the ru
EASA/AMC 25-13 […] if the section of the runway surface that is covered with standing w
A contaminated runway can either be covered with a FLUID contaminant (like
standing water, slush or snow) [PRH A1-2.2.5.3.1. Fluid Contaminants] or with
a HARD contaminant (like compacted snow or ice) [PRH A1-2.2.5.3.2. Hard
Contaminants].
HARD Contaminant
Corresponding contaminant
Wet, ice, compacted snow
Acceleration / Deceleration
Affect deceleration only, acceleration unaffected
Cause
Reduced tire-to-ground friction (No additional drag fo
Result
Longer stopping distance only
Assumed Temperature Reduced Thrust is not allowed on contaminated
runways.
If TOW on contaminated runway becomes VMCG limited, the use of Derate
(not Reduced) thrust might increase V1MCG Limit Weight, due to lower
VMCG.[PRH A1-3.2.1. Derated takeoff thrust]
Regulations do not restrict the use of a clearway on contaminated
runways. [PRH A1-2.2.5.3.5. Additional considerations - 2nd dot]
IEM OPS 1.490 Operation on runways contaminated with water, slush, snow or ice implie
4.1. CONTAMINATED RUNWAY – FLUID CONTAMINANT
[Slush/Standing Water Takeoff]
4.1.1. Maximum Allowable TOW
Use OAT and Wind component to find BRLW and CLTOW on the (DRY) TL
chart of the intended takeoff runway/intersection.
Apply (substract) weight corrections – AI / Eng Bleed / QNH (if < 1013, else
add) – as applicable to find BRLWDRY and (corrected) CLTOW.
Use BRLWDRY (which can be taken for DRY/FIELD OBSTACLE LIMIT
WEIGHT) as input for FCOM/PI SLUSH/STANDING WATER TAKEOFF –
WEIGHT ADJUSTMENT table, with the deposit’s Water Equivalent Depth and
the applicable PA, to find the Weight Adjustment value the BRLWDRY needs to
be corrected with to find BRLWCNTM.
Determine V1(MCG) Limit Weight from FCOM/PI SLUSH/STANDING
WATER TAKEOFF – V1(MCG) LIMIT WEIGHT table, using the deposit’s
Water Equivalent Depth, ASDA and PA as input.
Use the most limiting (lowest) of (corrected) CLTOW, BRLWCNTM and
V1(MCG)LW as the PLTOW.
Check PLTOW against the (Certified) Structural TOW to find the Maximum
Allowable TOW.
4.1.2. V Speeds
4.1.2.1. Using FCOM
4.1.2.2. Using FMC
With actual ZFW and PLANNED TOF entered on PERF REF-page of the FMC,
TAKEOFF REF-page 1/2 shows correct VR and V2 speeds.
With FMC/TAKEOFF REF-page 2/2 filled out correctly with actual wind and
runway slope, TAKEOFF REF-page 1/2 shows balanced V1DRY.
Normally a single value of (average) runway slope is available where the actual
slope may vary along the runway. A non-lineair runway slope may have an
adverse effect on aircraft acceleration or deceleration, not reflected in the
performance calculations.
Correct the FMC/balanced V1DRY for unequal clearway/stopway, as
applicable. [PRH A1-2.2.4.1.2. Required unbalancing]
FMC does not provide the correct V1 for a contaminated runway, therefore
FCOM/PI SLUSH/STANDING WATER TAKEOFF – V1 ADJUSTMENT table
needs to be applied to adjust the FMC/balanced V1DRY (corrected for unequal
clearway-stopway, if applicable), in order to account for the reduced acceleration
and deceleration capability due to the (fluid) contaminant on the runway. [PRH
A1-2.2.4.2. Rebalancing]
Check V1 against VMCG from FCOM/PI SLUSH/STANDING WATER
TAKEOFF – V1(MCG) table and use the higher as V1.
Note (from table data) that with increasing contaminant’s depth, V1 adjustment
becomes less negative due to decreasing acceleration capability.[PRH A12.2.4.2. Rebalancing]
4.2. CONTAMINATED RUNWAY – HARD CONTAMINANT
[Slippery Runway Takeoff]
4.2.1. Maximum Allowable TOW
Use OAT and Wind component to find BRLW and CLTOW on the (DRY) TL
chart of the intended takeoff runway/intersection.
Apply (substract) weight corrections – AI / Eng Bleed / QNH (if < 1013, else
add) – as applicable to find BRLWDRY and (corrected) CLTOW.
Use BRLWDRY (which can be taken for DRY/FIELD OBSTACLE LIMIT
WEIGHT) as input for FCOM/PI SLIPPERY RUNWAY TAKEOFF – WEIGHT
ADJUSTMENT with the Reported Braking Action and applicable PA, to find the
Weight Adjustment value the BRLWDRY needs to be corrected by to find
BRLWCNTM .
Determine V1(MCG) Limit Weight from FCOM/PI SLIPPERY RUNWAY
TAKEOFF – V1(MCG) LIMIT WEIGHT table, using the Reported Braking
Action, ASDA and PA as input.
Use the most limiting (lowest) of (corrected) CLTOW, BRLWCNTM and
V1(MCG)LW as the PLTOW.
Check PLTOW against the (Certified) Structural TOW to find the Maximum
Allowable TOW.
4.2.2. V Speeds
4.2.2.1. Using FCOM
4.2.2.2. Using FMC
With actual ZFW and PLANNED TOF entered on PERF REF-page of the FMC,
TAKEOFF REF-page 1/2 shows correct VR and V2 speeds.
With FMC/TAKEOFF REF-page 2/2 filled out correctly with actual wind and
runway slope, TAKEOFF REF-page 1/2 shows balanced V1DRY.
Normally a single value of (average) runway slope is available where the actual
slope may vary along the runway. A non-lineair runway slope may have an
adverse effect on aircraft acceleration or deceleration, not reflected in the
performance calculations.
Correct the FMC/balanced V1DRY for unequal clearway/stopway, as
applicable. [PRH A1-2.2.4.1.2. Required unbalancing]
FMC does not provide the correct V1 for a contaminated runway, therefore
FCOM/PI SLIPPERY RUNWAY TAKEOFF – V1 ADJUSTMENT table needs
to be applied to adjust the FMC/balanced V1DRY (corrected for unequal
clearway-stopway, if applicable), in order to account for the reduced deceleration
capability due to the (hard) contaminant on the runway. [PRH A1-2.2.4.2.
Rebalancing]
Check V1 against VMCG from FCOM/PI SLIPPERY RUNWAY TAKEOFF –
V1(MCG) table and use the higher as V1.
'SLIPPERY WHEN WET’ (NOTAM) Runway friction can be divided into 3 levels: 1. Des
5. INOPERATIVE EQUIPMENT
ACCELERATION AND/OR DECELERATION AFFECTED
The normal airplane performance is based on the assumption that all equipment
is operating normally, so in case of inoperative or deactivated equipment,
performance adjustments have to be applied.
5.1. ANTISKID INOP
Only allowed on a dry runway.
Reduced thrust takeoff not allowed.
Improved climb is not allowed. [PRH A1-2.3.2. Improved Climb]
Because deceleration is affected, a weight and V1 speed adjustment is required
for which a simplified method can be found in the FCOM PI/TEXT section.
The FCOM method can be overruled by a method mentioned in MEL 32-02
[Antiskid System] or your company’s substitute.
Apply weight adjustment on BRLWDRY.[PRH C1-2.1. MTOW Dry runway]
Apply V1 speed adjustment on V1.
Determine V1 for BRLWDRY,ANTISKID INOP (corrected for OAT, PA,
runway slope, wind and clearway/stopway), compare this to V1 determined for
the actual TOW [PRH C1-2.3. V-speeds Dry runway] and use the lower as V1.
If the resulting V1 is less than VMCG, V1 must be set equal VMCG. Takeoff is
permitted with V1=VMCG, provided the ASDA is at least the value mentioned
in FCOM PI/TEXT.
Special “Antiskid Inoperative” TL-tables can be generated which are more
accurate and might therefore be less restrictive.
5.2. THRUST REVERSER INOP
Since no credit is taken into account for the use of reverse thrust on a dry
runway, an inoperative thrust reverser has no effect on dry runway takeoff
performance calculations.
On a non-dry runway, because deceleration is affected, a weight and V1
adjustment is required if 1 or both T/R's are inoperative or deactivated (not
necessarily accompanied by illumination of the REVERSER light).
Your company might prohibit the use of reduced takeoff thrust.
5.2.1. Wet Runway
The way the weight and V1 adjustments have to be applied depends on how
BRLWWET is determined.
Apply weight adjustment on BRLWWET.
If BRLWWET is determined from a WET TL-chart[PRH C1-3.1. Using wet-TL
chart], this weight needs to be adjusted (lowered) according to a simplified
method which can be found in the FCOM PI/TEXT section. This FCOM method
can be overruled by a method mentioned in MEL 78-01 [Thrust Reverser
Systems], or your company’s substitute.
If BRLWWET is determined from a DRY TL-chart (no WET TL-chart
available), use the method as described in chapter C1-3.2., but apply FCOM/PI
SLIPPERY RUNWAY TAKEOFF – REPORTED BRAKING ACTION
GOOD – NO REVERSE THRUST tables.
Determine V1 according the flowchart below,
or apply V1 adjustment according FCOM/PI SLIPPERY RUNWAY
TAKEOFF – V1 ADJUSTMENT – REPORTED BRAKING ACTION
GOOD –NO REVERSE THRUST to the normal Dry V1, compare the result to
VMCG and take the higher as V1.
If the resulting V1 is less than VMCG, V1 must be set equal VMCG. Takeoff is
permitted with V1=VMCG, provided the ASDA is at least the value mentioned
in FCOM PI/TEXT.
5.2.2. Contaminated Runway
Determine BRLWCNTM and V1 as in chapter C1-4.1. or chapter C14.2. (depending on the contaminant type), but use the NO REVERSE THRUST
tables.
5.3. EEC ALTN MODE
According to the MEL 73-11 [Electronic Engine Control] Dispatch is allowed
with both EECs in ALTN mode, provided performance adjustments are applied.
The EEC aims for constant N1 during the takeoff run while airspeed increases.
With EEC in ALTN mode, acceleration is affected due to variations in N1,
requiring higher takeoff speeds and a lower PLTOW.
Variations in N1 due to EEC ALTN mode
Adjustments on PLTOW (divided per performance limit situation Field /
Obstacle / Tirespeed / Climb), V1, VR and V2 (corrected for OAT / PA / slope /
wind / runway condition / clear- and stopway) can be found in FCOM/PI Section
ALTERNATE MODE EEC.
Depending on engine thrust rating, speed or other performance adjustments
might not be necessary.
Reduced thrust takeoff is not allowed.
5.4. AUTO SPEEDBRAKE INOP
In case of an RTO with the auto speedbrake inoperative, the speedbrake can still
be pulled manually (pulling the speedbrake is part of the RTO-drill), therefore no
penalty applies to the takeoff situation.
(Auto speedbrake system inop for landing - Dispatch / Inflight)
1. DISPATCH CALCULATIONS
DETERMINATION MAX ALLOWABLE LANDING WEIGHT
Landing dispatch calculations must be made for destination and alternate airport,
which are either planned during dispatch or re-planned inflight.
The Maximum Allowable LDW is determined from the most limiting of the
(Certified) Sructural LDW and the Performance Limit LDW, which in turn is the
lowest of the Landing Field Limit Weight and Landing Climb Limit Weight.
(1)Determine LFLW for the most limiting of:
(A) the most favorable (normally the long
LCLW meets certain minimum climb gradients [PRH A3-2.3. Approach and
Landing climb requirement], but needs to be restricted more in cases where the
minimum required go-around climb gradient is higher (due to terrain or
obstacles in the (missed) approach segment). This restricted LCLW can be
determined by using the FCOM/PD GO-AROUND CLIMB GRADIENT table
in reverse [PRH B2-1.3. Go-around climb gradient].
Also:
IEM-OPS 1.510 The missed approach procedure of an instrument approach as shown on in
Additional requirement: When expecting a Cat II/III approach, the minimum
achievable go-around climb gradient must be 2.5%.
Besides regulatory restrictions, the Maximum Allowable LDW can also be
limited by operational (brake cooling) restrictions regarding a quick
turnaround [PRH C2-3.1. Quick Turnaround].
One of the input data to be used in several tables is the LDA, which is equal to
the distance beyond the (displaced) threshold.
On Jeppesen plates for example, this can be found on the airport plan.
Determination LDA using JEPPESEN data
In case of a planned autoland the manufacturer advices to substract 185 meters
(600 ft) from the LDA in order to obtain the corresponding LFLW.
2. INFLIGHT CALCULATIONS
DETERMINING LANDING DISTANCE REQUIRED AND GO-AROUND
GRADIENT
2.1. REQUIRED CALCULATION
EU-OPS 1.400 Before commencing an approach to land, the commander must satisfy hims
For the actual LDW, with the actual landing configuration under the actual
landing circumstances [ATIS], the following must be checked:
LDR must not exceed the LDA.
The achievable go-around climb gradient must be equal or higher than the
required go-around climb gradient.
2.1.1. Landing Distance Required
The LDR determined from the QRH/PI (NON) NORMAL CONFIGURATION
LANDING DISTANCE table [PRH B2-2.1. Landing distance required], must
not exceed the LDA [PRH A3-1.1. Landing distance available].
(1)Resulting from Non Normal Checklist. (2)Different tables for Flaps 30 and Flaps 40. (3
Regulations do not require margins in determination of LDR, but when
determining the LDR when the runway is not dry, a margin of 15% is
recommended which is included in the NORMAL CONFIGURATION
LANDING DISTANCE data.
Your company may require an additional margin on the LDR. This margin can
either be a fixed value or a percentage. Using the values for Max Autobrake
instead of Max Manual Braking may also serve as a margin.
Required Landing Distance
Additional Inflight Requirement
In case the aircraft was dispatched with an ELW exceeding the LFLW
(determined with no credit for headwind) according EU-OPS 1.515 [PRH A32.2.1. LFLW-Dispatch requirements], the actual LDW must not exceed the LFLW
determined with credit for the actual wind.
Additional information regarding braking performance data can be found in
chapter C1-4.
2.1.2. Go-Around Climb Gradient
The achievable go-around climb gradient, determined from the FCOM/PD GOAROUND CLIMB GRADIENT table [PRH B2-1.3. Go-around climb gradient],
must be equal or higher than the required go-around climb gradient as published
on the approach plate.
(1) Published approach minima are normally based on a missed approach gradient of 2.5%
2.2. FACTORS AFFECTING LANDING DISTANCE
The LDR determined from the QRH/PI (NON) NORMAL CONFIGURATION
LANDING DISTANCE table [PRH B2-2.1. Landing distance required], assumes
a touchdown point of 1000 feet, which may not be achievable in the actual
operation. Several factors play a role in the actual touchdown point of the
aircraft, thereby affecting the actual landing distance.
2.2.1. Autoland
Due to the autopilot’s flare behavior, the aircraft will touchdown further down
the runway with an autoland than with a manual landing. The additional landing
distance must be taken into account when making an autoland. A 15% margin is
recommended, but your company may also choose to add a fixed value on the
normal LDR.
The manufacturer advices to add 185 meters (600 feet) to the normal LDR to
obtain the autoland LDR.
Autoland flight tests revealed that the average touchdown point will be at 460
metres (1500 feet) from the threshold. With a statistical certainty of 99.7% the
touchdown will occur within 645 metres (2100 feet) from the threshold.
CS-AWO 142 [Automatic] Landing distance The landing distance required must be establ
CS-AWO 342 [Automatic] Landing distance If there is any feature of the system or the ass
2.2.2. Aiming Point Marking
For ICAO marked runways with a LDA of 2400 meters (8000 feet) or less the
beginning of the aiming point marking is about 305 meters (1000 feet) from the
threshold, but for ICAO marked runways with a LDA more than 2400 meters
(8000 feet) this marking starts about 400 meters (1300 feet) from the threshold.
The aiming point markings are 45 – 60 meters (150 – 200 feet) long.
Aiming Point ICAO marked runway
The aiming point marking on the runway is not always positioned at 1000 feet
(305 meters) from the threshold, so when aiming for these markings, the actual
touchdown point might be more than 1000 feet (305 meters) from the threshold,
thereby increasing the actual landing distance.
When landing at the end of the aiming point marking, the actual landing
distance might be up to 500 feet (150 meters) longer than the operational
landing data assume.
2.2.3. Threshold Crossing Height
Manufacturer’s operational landing data are based on a threshold crossing height
(TCH) of 50 feet.
The actual height an aircraft crosses the threshold with, depends on several
factors such as the position of the aiming point, the accuracy and glide path
angle of the approach used, the PAPI / VASI accuracy and calibration reference
and piloting accuracy.
Rule of thumb: TCH + 10ft = LDR + 60m
In case the the threshold is crossed at a height of 100 feet following a 3-degree
glidepath, the aircraft will touch the runway about 1000 feet (300 meter) further
down the runway compared to a TCH of 50 feet.
Effect of TCH on landing distance
Crossing the threshold at a height lower than 50 feet at a shallower approach
angle, requires more thrust compared to a 3-degree glidepath, increasing the
chance of floating with a longer landing distance as a result.
2.2.4. Threshold Crossing Speed
Manufacturer’s operational landing data assume a threshold crossing speed of
VREF.
The speed at the 50 feet screenheight over the threshold is normally the Final
Approach Speed (FAS) which is, as a standard, minimum 5 knots faster than
VREF.
Note that landing distance data assume VREF over the threshold.[PRH B2.2.1.
Landing distance required]
The actual speed an aircraft crosses the threshold with depends on several
factors, such as steady wind speed, wind gusts, flapsetting and piloting accuracy.
A 10% increase in FAS results in a 20% increase in required landing distance,
thereby assuming a normal flare and touchdown (without floating), but in case of
floating (which possibility is increased due to the higher speed) this increase
might raise up to 60%.
Rule of thumb: FAS + 10kts = LDR + 100m (dry rwy) / 170m (wet rwy)
Rule of thumb: FAS + 10kts = LDR + 800m due to floating
Flying 10 knots faster than assumed, might require up to 200 meters more
landing distance without floating, and up to 1000 meters including floating,
depending on runway condition and autobrake setting.
The increased flare distance due to floating resulting from the excess speed
usually has a bigger effect on the actual landing distance than the increased
ground roll distance, because the deceleration the aircraft can achieve in the air
is only a fraction of what it can achieve on the ground, even on slippery
runways.
2.3. OTHER LANDING DISTANCE CONSIDERATIONS
2.3.1. Dispatch Data VS. Inflight Data
The following figure shows the relation between the certified landing distance
(dispatch requirement) [PRH A3-2.2.2. Certified Landing Distance] and the
operational (required) landing distance. To be able to compare these, both the
certified and the operational landing distance are based on MLW. The
operational landing distance is considered with varying surface conditions
(Airplane Braking Coeffient [PRH C1 Braking performance data]).
Dispatch data VS operational data
Note that EASA regulation require the operator to not only consider wet runway
data in the dispatch calculations, but also (approved) contaminated runway
landing distance data, in case the runway is expected to be contaminated
(slippery) [PRH A3-2.2.5. LFLW contaminated (slippery) runway].
2.3.2. Reverse Thrust with Manual Brakes VS.
Autobrakes
The effect of thrust reversers in combination with manual or autobrakes is given
below:
DRY runway
MANUAL BRAKES
Thrust reversers DO increase the deceleration rate.
AUTOBRAKES
Thrust reversers typically DO NOT increase the deceleration r
The figure on the next page shows the typical 737 airplane deceleration
capability on different runway conditions versus autobrake settings.
The scheduled deceleration rate with maximum autobrake setting will always be
reached on a dry runway with wheelbrakes only. According this figure, the same
is true for A/B setting 3 on a runway with braking action GOOD.
On a runway with braking action MEDIUM, the scheduled deceleration rate of
A/B MAX will not be reached, and the scheduled deceleration rate for A/B 3
will be reached with the combined use of wheelbrakes and revere thrust.
Deceleration capability VS. autobrake setting
As runway friction deteriorates, it is less likely that the airplane will achieve the
scheduled autobrake deceleration rates in which case the actual runway stopping
distance will be determined by the runway friction capability.
3. BRAKE COOLING
DISPATCH AND INFLIGHT CALCULATIONS
3.1. DISPATCH - Quick Turnaround
Besides the LFLW and LCLW, operation can also be limited by the maximum
weight for a quick turnaround (Quick Turnaround Limit Weight – QTLW),
thereby limiting the LDW.
The QTLW protects the wheel fuse plugs from melting during a subsequent
takeoff.
If a Brake Temperature Monotoring System (BTMS) is installed, it may be used
instead of the QTLW table.
If LDW exceeds QTLW, a minimum required ground time (see table in PD)
applies, after which it must be checked that fuse plugs have not melted, before
executing a subsequent takeoff.
3.2. INFLIGHT - Recommended Brake Cooling
Recommended Brake Cooling Schedule provides brake energy protection if it
becomes necessary to reject the takeoff.
Recommended Brake Cooling Schedule provides the only means of evaluating
brake cooling requirements following repeated landings at short time intervals or
a rejected takeoff.
QUICK TURNAROUND LIMIT WEIGHT
RECOMMENDED
Regulatory requirement (restriction).
Advisory information
Guarantees only fuse plug melt protection for the next takeoff.
Guarantees fuse plug
Only means of evalu
I. RUNWAY STATE MESSAGE
METAR
Runway State Message: Information on runway conditions by an 8-figure group
appended to METAR.
Also referred to as (METAR) Runway Report.
Report is based on the same observation / measurement as the SNOWTAM and
is repeated with every subsequent weather report (METAR) until a new report is
made.
For practical reasons not necessarily refreshed at the same 30 minutes interval of
a METAR. Repetition of a previous Runway State Message may mean that no
significant changed have taken place.
If an airport is closed due to snow or snow/ice removal, the term SNOCLO//
may replace the 8-figure code group.
II. SNOWTAM
NOTAM
SNOWTAM: A specialized NOTAM notifying the presence of hazardous
runway conditions due to snow, ice etc. by using a specified ICAO format.
Available on the NOTAM or at the AIS office as soon as the presence of
contamination is considered to be operationally significant.
A new SNOWTAM should normally be issued every 6 hours. For an airport with
no night operations or closed at night, a new SNOWTAM should be issued 2
hours before the airport is reopened.
The validity of a SNOWTAM is maximum 24 hours. If the validity expires a
new observation or measurement should be made even if conditions have not
changed and a new SNOWTAM should be issued.
III. GLOSSARY
Accelerate Stop Distance Available (ASDA)
The length of the takeoff run available plus the length of stopway, if such
stopway is declared available by the appropriate Authority and is capable of
bearing the mass of the aeroplane under the prevailing operating conditions.
Accelerate Stop Distance Required (ASDR)
The required distance to accelerate with all (N) engines operating to V1
(including 1 second recognition time between VEF and V1) plus the required
distance to travel 2 seconds at constant speed V1 (to allow for the transition from
acceleration to the stopping configuration) plus the required distance to
decelerate from V1 to a full stop.
Airplane Braking Coefficient (µB)
The ratio of the stopping force contribution of the wheel brakes to the average
airplane weight on wheels. Airplane braking coefficient (µB) is a different
parameter than the runway friction coefficient (µ).
Aquaplaning (Hydroplaning)
Partial or total loss of contact and friction between the tire and the runway which
occurs when the tire cannot squeeze anymore of the fluid contaminant layer
between its tread and lifts off the runway surface.
Balanced Takeoff
A takeoff for which ASDR equals TODR.
Brake Energy Limit TOW
A takeoff weight which, for a given runway length, is limited by the amount of
energy that can be absorbed by the brakes during an aborted takeoff.
Braking Action
A subjective description of airplane stopping capability on a slippery runway in
(ICAO) terms of Good, Good to Medium, Medium, Medium to Poor and Poor.
Certified Landing Distance
The Flight Test Demonstrated Landing Distance plus a required margin.
Clearway
An area beyond the runway, not less than 152 m (500 ft) wide, centrally located
about the extended centreline of the runway, and under the control of the airport
authorities.
Climb gradient
The ratio, expressed as a percentage, of the change in geometric height divided
by the horizontal distance travelled in a given time.
Climb Limit TOW
A takeoff weight which is limited by the ability of the airplane to achieve the
minimum required climb gradient with one engine inoperative in still air.
Compacted snow
Snow which has been compressed into a solid mass such that the aeroplane
wheels, at representative operating pressures and loadings, will run on the
surface without causing significant rutting.
Contaminated runway
A runway where more than 25% of its surface area (whether in isolated areas or
not) within the required length and width being used is covered by the following:
• Surface water more than 3 mm (0.125 inch) deep, or by slush, or loose snow,
equivalent to more than 3 mm (0.125 inch) of water;
• Snow, which has been compressed into a solid mass which resists further
compression and will hold together, or break into lumps if picked up (compacted
snow); or
• Ice, including wet ice.
Cost Index (CI)
Parameter which reflects the relationship between time-related costs versus fuel
costs.
Damp runway
A runway with a surface not being dry, but when the moisture on it does not give
it a shiny appearance.
Derated takeoff thrust
A takeoff thrust level less than the maximum takeoff thrust, for which exists in
the AFM a set of separate and independent, or clearly distinguishable, takeoff
limitations and performance data that complies with all the takeoff requirements.
When operating with a derated takeoff thrust, the value of the thrust setting
parameter which establishes thrust for takeoff is presented in the AFM and is
considered a normal takeoff operating limit.
Driftdown Ceiling
The maximum altitude that can be flown at the driftdown speed with one engine
inoperative.
Dry runway
A runway which is neither wet nor contaminated, and includes those paved
runways which have been specially prepared with grooves or porous pavement
and maintained to retain ‘effectively dry’ braking action even when moisture is
present.
Dry (loose) snow
Fresh snow that can be blown, or, if compacted by hand, will fall apart upon
release (also commonly refered to as loose snow), with an assumed specific
gravity of 0.2.
ECON speed
Speed based on the cost index, therefore offering the least costs.
EGT Margin
The difference between the EGT Red Line and the EGT, observed on an engine
at TO/GA with OAT greater than the Corner Point OAT.
Engine Failure speed (VEF)
The calibrated airspeed at which the critical engine is assumed to fail.
Field Length Limit TOW
A takeoff weight which is limited by the ability of the airplane, following an
engine failure at VEF, to either continue and reach the screenheight or stop
within the runway limits.
Final Approach Speed (FAS)
The airspeed to be maintained down to 50 feet over the threshold.
Flare distance (takeoff)
The distance from liftoff to the point where the screenheight is reached.
Flare distance (landing)
The distance from 50ft over the threshold to the touchdown point.
Flight Test Demonstrated Landing Distance
The shortest landing distances possible for a given airplane weight representing
the best performance the airplane is capable of (without reversers) for the
conditions. It is the demonstrated distance on a dry runway, measured from a
height of 50 feet above the landing surface using an aggressive touchdown
technique, maximum manual wheel braking and speed brakes, but without credit
for reverse thrust during the landing ground roll.
Fluid contaminants
Contaminants with a measurable depth which are drag producing and tire
braking friction reducing.
Fuel Mileage (Specific Range)
The distance the airplane can fly using a given amount of fuel.
Go-around climb gradient
The ratio, expressed as a percentage, of the change in geometric height divided
by the horizontal distance travelled in a given time during the go-around.
Grooved or Porous Friction Course (PFC) runway
A paved runway that has been prepared with lateral grooving or a porous friction
course (PFC) surface to improve braking characteristics when wet.
Gross Drifdown Flight Path
Actual drifdown flight path which is required to be more penalizing than the Net
Driftdown Flight Path by a regulatory margin (1.1 % for a 2 engine aircraft).
Gross T/O Flight Path
Actual flight path with one engine inoperative which is required to be more
penalizing than the Net T/O Flight Path by a regulatory margin (0.8% for a 2
engine aircraft).
Hard contaminants
Solid contaminants with no measurable depth (depth is not relevant) which are
tire braking friction reducing.
Hydroplaning (Aquaplaning)
Partial or total loss of contact and friction between the tire and the runway which
occurs when the tire cannot squeeze anymore of the fluid contaminant layer
between its tread and lifts off the runway surface.
Ice
Water which has frozen on the runway surface, including the condition where
compacted snow transitions to a polished ice surface.
Improved Climb
Trading excess runway for higher takeoff speeds to increase the aerodynamic
efficiency, resulting in better climb performance.
Landing Climb Limit weight
A landing weight which is limited by the approach and landing climb
requirements.
Landing Distance Available (LDA)
The length of the runway which is declared available by the appropriate
Authority and suitable for the ground run of an aeroplane landing.
Landing Field Limit Weight (LFLW)
The maximum weight for which the Landing Distance Available (LDA) equals
the required Certified Landing Distance.
Lift off speed (VLOF)
The calibrated airspeed at which the airplane first becomes airborne.
Line-up corrections
The adjustments made to the available runway length to account for the fact that
some of the runway length is used for aligning the aircraft on the runway prior to
beginning the takeoff roll.
Loose (dry) snow
Fresh snow that can be blown, or, if compacted by hand, will fall apart upon
release (also commonly refered to as loose snow), with an assumed specific
gravity of 0.2 kg/m3.
Maximum Brake Energy speed (VMBE)
The maximum speed, for a given TOW, at which the brakes are able to absorb
the built-up energy (which is a function of weight and speed) and still be
effective.
Maximum Range Cruise speed (MRC)
The speed at which, for a given weight, the highest possible fuel mileage is
achieved.
Minimum Control speed – Air (VMCA)
The calibrated airspeed, at which, when the critical engine is suddenly made
inoperative, it is possible to maintain control of the aeroplane with that engine
still inoperative, and maintain straight flight with an angle of bank of not more
than 5º.
Minimum Control speed – Ground (VMCG)
The calibrated airspeed during the take-off run at which, when the critical engine
is suddenly made inoperative, it is possible to maintain control of the aeroplane
using the rudder control alone.
Minimum Unstick speed (VMU)
The lowest speed at which the aircraft can lift off the ground and safely fly away.
Net Driftdown Flightpath
A theoretical flightpath which must clear all obstacles vertically with at least
2000 feet during descent and with at least 1000 feet after level-off and must
maintain level flight at least 1500 feet above the airport of intended landing,
meeting weather and landing performance requirements.
Net T/O Flight Path
Theoretical flight path starting at the end of the TODA at 35 feet and clearing all
obstacles by at least 35 feet.
Obstacle Limit TOW
A takeoff weight which is limited by the ability of the airplane to clear obstacles
in the takeoff path by the minimum required margin.
Optimum Altitude
Altitude which offers the highest fuel mileage (or specific range).
Porous Friction Course (PFC) or grooved runway
A paved runway that has been prepared with lateral grooving or a porous friction
course (PFC) surface to improve braking characteristics when wet.
Quick Turnaround Limit Weight
The maximum landing weight for which there is no minimum ground time
required with respect to possible fuse plug melting. This weight does not
guarantee sufficient brake energy absorbtion in case of a subsequent aborted
takeoff.
Rotation speed (VR)
The speed at which the pilot initiates action to raise the nose gear off the ground.
Rebalancing
Rescheduling V1 in order to fix the disturbed balance between stop and go,
affected by reduced acceleration or deceleration capability, with a lower Field
Length Limit TOW as a result.
Reduced takeoff thrust
A takeoff thrust less than the takeoff (or derated takeoff) thrust. The aeroplane
takeoff performance and thrust setting are established by approved simple
methods, such as adjustments, or by corrections to the takeoff or derated takeoff
thrust setting and performance. When operating with a reduced takeoff thrust,
the thrust setting parameter which establishes thrust for takeoff is not considered
a takeoff operating limit.
Reference Speed (VREF)
The reference landing approach speed for a defined landing configuration.
Runway Friction
The capability of the runway surface to convert the vertical load on the braked
wheels into a horizontal force to stop the airplane. The Greek letter µ (‘mu’) is
typically the symbol for friction and represents the percentage of the vertical
load converted into a horizontal force.
Runway End Safety Area (RESA)
An area symmetrical about the extended runway center line and adjacent to the
end of the strip primarily intended to reduce the risk of damage to an airplane
undershooting or overrunning the runway.
Runway Safety Area
The surface surrounding the runway prepared or suitable for reducing the risk of
damage to airplanes in the event of an undershoot, overshoot, or excursion from
the runway.
Runway State Message
Information on runway conditions by an 8-figure group appended to METAR.
Second segment climb requirement
Regulations require the aircraft to be able to reach a climb gradient of 2.4% in
the part of the takeoff segment which extends from the point where the gear is
retracted until the acceleration height (minimum 400ft AAL), which is generally
the most limiting climb requirement.
SID deviation point
A specified point on the SID where an emergency turn deviates from the normal
departure route.
SID restriction point
A specified point (or altitude) on the SID after (or above) which following the
SID assures sufficient obstacle clearance with one engine inoperative.
Slush
Partly melted snow or ice with a high water content, from which water can
readily flow, with an assumed specific gravity of 0.85.
SNOWTAM
A specialized NOTAM notifying the presence of hazardous runway conditions
due to snow, ice etc. by using a specified ICAO format. It is available on the
NOTAM or at the AIS office as soon as the presence of contamination is
considered to be operationally significant.
Specific Gravity
Relative density defined as the ratio of the density of a given substance to the
density of water when both substances are at the same temperature. Substances
with a specific gravity greater than 1 are more dense than water, and those with a
specific gravity of less than 1 are less dense than water. Expressed as a
dimensionless value.
Specific Range (Fuel Mileage)
The distance the airplane can fly using a given amount of fuel.
Stall speed (VS)
The minimum steady flight speed at which the airplane is controllable.
Standing water
Water of a depth greater than 3mm.
Stopway
An area beyond the takeoff runway, no less wide than the runway and centered
upon the extended centreline of the runway, able to support the aeroplane during
an abortive takeoff, without causing structural damage to the aeroplane, and
designated by the airport authorities for use in decelerating the aeroplane during
an abortive takeoff.
Structural weight
The maximum weight the airframe, landing gears and wings can support.
Takeoff Decision speed (V1)
The speed used as a reference in the event of engine or other failure in deciding
whether to continue or reject the takeoff.
Takeoff Distance Available (TODA)
The length of the takeoff run available plus the length of the clearway available.
Takeoff Distance Required (TODR)
The greater of:
(1) The required distance to accelerate with all (N) engines operating to VEF,
plus the required distance to accelerate with one engine inoperative (N-1) to V2
at a screenheight of 35 feet (wet or contaminated runway: 15 feet) above the
takeoff surface; or
(2) The required distance to accelerate with all (N) engines operating to a
screenheight of 35 feet, plus a distance margin of 15%.
Takeoff Safety speed (V2)
The target speed to be reached at the screenheight, assuming an engine failure at
or after V1.
Takeoff Run Available (TORA)
The length of runway which is declared available by the appropriate Authority
and suitable for the ground run of an aeroplane taking off.
Takeoff Run Required (TORR)
The greater of:
(1) The distance to takeoff and climb to a point equidistant between lift off and
the 35 feet height point with a failure of the critical engine at VEF; or
(2) 115 percent of the distance to takeoff and climb to a point equidistant
between lift off and the 35 feet height point with all engines operating.
Notes:
1. On a wet runway, the height requirement with a failed engine is 15 feet.
2. On a wet runway, the takeoff run required is the distance to takeoff and climb
to 15 feet with a failure of the critical engine at VEF.
TAS (True Airspeed) effect
The effect that, with assuming a higher than actual OAT when applying the
assumed temperature reduced takeoff thrust method, the actual TAS is lower
than assumed, leaving a performance margin.
Thrust effect
The effect that, with assuming a higher than actual OAT when applying the
assumed temperature reduced takeoff thrust method, the actual thrust output is
higher than assumed, leaving a performance margin.
Tire Speed Limit TOW
A takeoff weight that requires a liftoff speed equal to the tire speed limit.
Unbalancing
Using any value other than balanced V1.
V1MCG Limit Weight
The maximum weight for which the airplane can accelerate to VMCG and just
be able to stop within the available accelerate stop distance.
Water Equivalent Depth (WED)
Converted fluid contaminant layer thickness equivalent to water layer thickness.
Wet runway
A runway where the surface is covered with water, or equivalent precipitation,
less than specified as ‘contaminated runway’, or when there is sufficient
moisture on the runway surface to cause it to appear reflective, but without
significant areas of standing water.
Wet snow
Snow that will stick together when compressed, but will not readily allow water
to flow from it when squeezed, with an assumed specific gravity of 0.5.
IV. ABBREVIATIONS
A
AAL Above Airport Level
A/B Autobrake
ABC Airplane Braking Coefficient
Act Actual
AFM-DPI Airplane Flight Manual – Digital Performance Information
(software)
AI Anti Ice systems (EAI / WAI)
AMC Acceptable Means of Compliance
AOA Angle Of Attack
APU Auxiliary Power Unit
ASD-A/R Accelerate Stop Distance – Available/Required
Ass Assumed
ATC Air Traffic Control
ATIS Automatic Terminal Information System
ATM Assumed Temperature Method
AWO All Weather Operations
B
BA Braking Action
BRLW Brake Release Limit Weight
BTMS Brake Temperature Monitoring System
C
CDU Control Display Unit
CFM (GE) Commercial Fan and (Snecma) Moteurs (engine manufacturer)
CG Center of Gravity
CI Cost Index
CL Lift coefficient
CL Centerline
CLD Certified Landing Distance
CLTOW Climb Limit Takeoff Weight
Corr Corrected
CNTM Contaminated
CS Certification Specifications
Cwy Clearway
D
D Drag
DD Driftdown
E
EAI Engine Anti Ice system
EASA European Aviation Safety Agency
EEC Electronic Engine Control
EFB Electronic Flight Bag
EGT Exhaust Gas Temperature
ELW Estimated (planned) Landing Weight
ETA Estimated Time of Arrival
F
F Force
FAR Federal Aviation Regulations
FAS Final Approach Speed
FCOM/PD Flight Crew Operations Manual / Performance Dispatch section
FCOM/PI Flight Crew Operations Manual / Performance Inflight section
FMC Flight Management Computer
FPPM Flight Planning & Performance Manual
FRT Flat Rated Temperature
FTDLD Flight Test Demonstrated Landing Distance
G
GA Go-Around
GS Ground speed
H
HAA Height Above Airport
HWC Head Wind Component
I
ICAO International Civil Aviation Organisation
Inop Inoperative
IEM Interpretative Explanatory Material
ISA International Standard Atmosphere
J
JAA Joint Aviation Authorities
JAR Joint Aviation Requirements
L
LCLW Landing Climb Limit Weight
LDA / R Landing Distance Available / Required
LDW Landing Weight
LE Leading Edge
LFLW Landing Field Limit Weight
LRC Long Range Cruise
LW Limit Weight
M
MAC Mean Aerodynamic Chord
Max Maximum
MCT Maximum Continuous Thrust
MEL Minimum Equipment List
METAR Meteorological Airport Report
min minimum
MRC Maximum Range Cruise
MTOW Maximum Takeoff Weight
N
N All engines operating
N-1 One engine inoperative
NG Next Generation
NM Nautical Mile
NOTAM Notice To Airmen
O
OAT Outside Air Temperature
OAA Obstacle Accountability Area
P
P Pressure
PA Pressure Altitude
PANS-OPS Procedures for Air Navigation Services - Aircraft Operations
PFC Porous Friction Course (runway surface type)
PLLDW Performance Limit Landing Weight
PLTOW Performance Limit Takeoff Weight
PRH Performance Reference Handbook (this guide)
Q
QNH Pressure at SL based on airport elevation
QRH/PI Quick Reference Handbook / Performance Inflight section
QTLW Quick Turnaround Limit Weight
R
RESA Runway End Safety Area
RTO Rejected Takeoff
RVR Runway Visual Range
RVSM Reduced Vertical Separation Minima
RWY(S) Runway(s)
S
SAFO Safety Alert for Operators
SID Standard Instrument Departure
SL Sea Level
SM Statute Mile
Spwy Stopway
T
T Thrust
TASSUMED Assumed temperature
TAS True Airspeed
Temp Temperature
TL (chart) Takeoff Limiting (chart)
T/O Takeoff
TODN Takeoff Distance - all engines operating
TODN-1 Takeoff Distance - one engine inoperative
TODA / R Takeoff Distance Available / Required
TOF Takeoff Fuel
TO/GA Takeoff / Go-Around thrust level
TORA Takeoff Run Available
TOW Takeoff Weight
T/R Thrust Reverser
TWC Tail Wind Component
TWY(S) Taxiway(s)
U
UTC Universal Time Coordinated
V
V1 Takeoff Decision speed
V1MCG V1 equal to VMCG
V2 Takeoff Safety speed
VEF Event speed (i.c.o. continued takeoff: Engine Failure speed)
VG Ground speed
VHP Hydroplaning speed
VLOF Liftoff speed
VMBE Maximum Brake Energy speed
VMCA Minimum Control speed – Air
VMCG Minimum Control speed – Ground
VMCL Minimum Control speed – Landing
VMU Minimum Unstick speed
VMINCLEAN Minimum Clean speed
VR Rotation speed
VREF Reference landing speed
VS Stall speed
VS1G Stall speed – unaccelerated (1G)
VSR Reference stall speed
VSR0 Reference stall speed landing configuration
VTIRE Maximum Certified Tire speed
V/S Vertical speed
W
W Weight
WAI Wing Anti Ice system
WED Water Equivalent Depth
Z
ZFW Zero Fuel Weight
V. REFERENCES
REGULATIONS
EASA
1. Certification Specifications for Large Aeroplanes, CS-25, Amendment 9
2. Certification Specifications for All Weather Operations, CS-AWO
3. Definitions and abbreviations used in Certification Specifications for
products, parts and appliances, CS-Definitions
4. EU-OPS Subpart F Performance General
5. EU-OPS Subpart G Performance Class A
ICAO
1. Procedures For Air Navigation Services Aircraft Operations (Pans-Ops, Doc
8168)
2. Annex 6, Part 1, Operation of International Commercial Air Transport –
Aeroplanes, 8th edition
3. Annex 14, Volume 1, Aerodrome design and operations, 4th edition
4. Ice- and Snowtable
OFFICIAL INFO BULLETINS / RECOMMENDATIONS
CAA
1. Landing Performance of Large Transport Aeroplanes, AIC 14/2006, feb 2006
2. Guidance for operations on a runway that is notified by NOTAM as ‘MAY BE
SLIPPERY WHEN WET’, FODCOM 28/2007
3. The importance of using performance data appropriate to the existing runway
conditions, FODCOM 03/2009
FAA
1. Runway Overrun Prevention, Advisory Circular (AC) 91-79, nov 2007
ARTICLES
Boeing
1. Driftdown and Oxygen Procedures Over High Terrain – Requirements and
Analysis Methods, Catherine Davis, sep 2003
2. Reduced Thrust Considerations, Dick Mayward, may 2004
3. Performance Margins, Paul Schmid, Performance Conference 2007
4. Landing on Slippery Runways, Paul Giesman, Performance Conference 2007
5. Improved Climb – Benefits, Method and other Considerations, Scott Brown,
Performance Conference 2007
6. Wet runway – Physics, Certification, Application, Paul Giesman, Performance
Conference 2007
NLR
1. A method for prediciting the rolling resistance of aircraft tires in dry snow,
NLR-TP-99240, G.W.H. van Es, 1999
2. Running out of runway, NLR-TP-2005-498, G.W.H. van Es, 2005
Flight Safety Foundation
1. International Regulations Redefine V1, Flight Safety Digest, oct 1998
2. A Review of Transport Airplane Performance Requirements Might Benefit
Safety, Flight Safety Digest, feb 2000
3. The Final Approach Speed, ALAR Briefing Note 8.2, Flight Safety Digest,
aug-nov 2000
4. Landing Distances, ALAR Briefing Note 8.3, Flight Safety Digest, aug-nov
2000
5. Wet or Contaminated Runways, ALAR Briefing Note 8.5, Flight Safety
Digest, aug-nov 2000