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1. SYNOPSIS OF PERFORMANCE COURSE.
The following are items which I think should be discussed in our presentation on Performance.
I suggest that they are formatted into a suitable power-point (or such) presentation.
Obviously please advise if you think items need to be added or removed. Performance is not my 'pet'
subject....not sure what is?! So I am asking for assistance please.
I don't think it is beneficial to delve too deep into the theory of Perf A, as this will just eat up
valuable time.
I suggest that we have the class complete a performance calculation form for a restrictive airport in
the summer time bringing in as many restrictive features as possible, such as MEL/TWC/INTEGRATED
PERFORMANCE etc. I suggest that we ask the students, when notified of their course, to bring in
either a copy of the QRH or have an electronic version (better option as it will be up to date)
available from their laptop/Ipad.
A hand-out of my winter brief should be handed out as I am not sure if all pilots received it by e-mail.
A hand-out of this performance presentation should also be given out and the students told it is not
necessary to take notes, so that they can concentrate more!
The items highlighted in red need your further attention if possible please!
PRESENTATION ITEMS FOLLOW.
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2. WE START WITH A FEW BASIC DEFINITIONS.
TAKE OFF DISTANCE (TOD).
The greater of either the distance to a height of 35 feet with an engine failure, or 115% of the all
engine distance to 35 feet.
CONTAMINATED RUNWAY.
A runway is considered to be contaminated when more than 25% of the runway surface area
(whether in isolated areas or not) within the required length and width being used is covered by the
following.
1. Surface water more than 3mm deep, or by slush, or loose snow, equivalent to more than 3mm of
water.
2. 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
3. Ice including wet ice.
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3. CONTAMINATED RUNWAY PERFORMANCE.
Operation on contaminated runways implies uncertainties with regard to runway friction and
contaminant drag and therefore to the achievable performance and control of the aircraft during
take-off, since the actual conditions may not completely match the assumptions on which the take-
off performance is based. If this is impracticable, take-off maybe considered provided the applicable
performance adjustments have been applied. In connection with contaminated runways, the
performance criteria remains unchanged from the requirements with the following exceptions.
1. The take-off mass must not exceed that permitted for take-off on a dry runway under the same
conditions.
2. Take-off screen height is presently reduced from 35 feet to 15 feet in case of one engine
inoperative.
3. Stopping distance includes the effect of reverse thrust (not applicable on a dry runway)
4. The use of assumed temperature method for reduced thrust or improved climb procedures must
not be used.
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4. WET RUNWAY.
A runway is considered wet when the runway surface is covered with water, or equivalent, less than
specified for contaminated runway above or when there is insufficient moisture on the runway
surface to cause it to appear reflective, but without significant areas of standing water.
WET RUNWAY PERFORMANCE.
When the runway is wet, take-off performance must be calculated considering the effects of
reduced braking capability. The take-off mass must not exceed that permitted for take-off on a dry
runway under the same conditions:
1. Take off screen height is presently reduced from 35 feet to 15 feet in case of one engine
inoperative.
2. Stopping distance includes the effect of reverse thrust.
3. Credit for clearway (area clear of obstacles at the runway end doesn’t have to be rollable, can be
gravel or water) is not permitted.
On a wet runway the V1 speed used is lower than if it is dry for a given aircraft weight. This is
because the maximum wheel braking force available will be less on a wet runway, so the aircraft will
have to brake from a lower speed for it to be stopped within the distance available. If engine failure
was recognised at this lower V1 and take-off was continued:
1. The aircraft will lift off after a longer run than from failure recognised at the dry V1 but the run
will not exceed TORA (Take Off Run Available).
2. The aircraft will reach a height of not less than 15 feet at the end of the TODA (Take Off Distance
Available, which is TORA plus the clearway), and V2 by the time 35 feet is reached.
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5. FACTORS AFFECTING TAKE OFF DISTANCE.
When using either the Runway Analysis or the take-off performance charts in the FPPM/AFM the
following factors must be taken into account:
1. The atmospheric pressure of the aerodrome.
2. The ambient temperature at the aerodrome.
3. The runway surface condition and the type of runway surface.
4. The runway slope in the direction of take-off.
5. Actual headwind or tailwind component.
6. Corrections, if any, due to use of air conditioning pack usage.
7. The loss, if any, of runway due to alignment of the aircraft prior to take-off.
(State that the allowance for a 180' turn on the runway is calculated in the Runway Analyses charts)
8. Any performance penalties resulting from dispatch with inoperative equipment.
9. NOTAMS.
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6. ENGINE INOPERATIVE CONSIDERATIONS.
Remember that take-off thrust is limited to 5 minutes, however, increased to 10 minutes in the
event of an engine failure.
At maximum take-off weight initial pitch attitude to aim for is 12.5' and at weights around maximum
landing weight 15'.
STANDARD ENGINE OUT PROCEDURE.
Climb straight ahead at V2 speed until acceleration height (minimum 1500 feet a.a.l) is achieved,
then:
1. Accelerate for flap retraction and simultaneously start a 15' bank turn if specified in the Engine
Out Procedure description. Retract flaps on schedule and accelerate to final segment climb speed,
V2+100 (i.e. Vref+98 knots)
NOTE: If the holding pattern is close in, flaps maybe left extended to maintain the required holding
speed (below 14,000 feet, generally 230 knots)
Maximum weight for holding clean is: xxxx
Maximum weight for holding with flap 1' is: xxxx
Maximum weight for holding with flap 5' is: xxxx
(Please calculate the above weights from the QRH as I do not have one with me!)
2. After flap retraction climb with Maximum Continuous Thrust to desired altitude for further action,
i.e. approach or diversion to another airport.
3. A bank angle of 25' is assumed only after reaching clean manoeuver speed.
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7. SPECIAL ENGINE OUT PROCEDURE.
Climb at V2 speed and follow specific navigational procedure as defined in analyses until
acceleration height (minimum 1500 feet a.a.l.) is achieved AND:
1. Accelerate for flap retraction. Retract flaps on schedule and accelerate to final segment climb
speed.
2. If the Engine Out Procedure requires a turn before reaching clean manoeuver speed a bank angle
of 15' is assumed. After clean manoeuver speed is reached, 25' bank is assumed.
3. After flap retraction climb with Maximum Continuous Thrust to desired altitude for further action,
i.e. approach or diversion to another airport. Continue climb for a minimum of one hold.
NOTE FOR BOTH STANDARD/SPECIAL ENGINE OUT PROCEDURES:
If a holding pattern is provided, the normal holding pattern is 5nm straight to the holding fix and a
turn with a radius of 2nm. A safety margin of 3nm is provided around the holding pattern. Unless
obstacle clearance is not a problem (e.g. over the sea) and the aircraft climb performance is
adequate, do not accept ATC radar vectors below MSA.
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8. ALTERNATE FORWARD CG LIMITS.
The use of Alt Fwd CG Limit requires less lift from the wing for the same weight of cargo. The
benefits of the performance gained maybe utilised in the following ways:
1. For the B747, for a given set of circumstances, i.e. runway length, airport elevation and ambient
temperature, an increase in take-off weight maybe in the order of 6000 kgs.
2. Maintain capability for the same take-off weight even if the OAT increases 6-8 degrees Celsius.
3. Less tail trim drag results in better climb capability and lower overall trip fuel burn. Alt Fwd CG
Limit take-off is allowed on dry and wet runways, but NOT on contaminated runways.
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9. RUNWAY ANALYSIS CALCULATIONS
INSERT A SCAN OF A RUNWAY ANALYSES CHART AND DISCUSS
(On R/R engines can maximum HWC be used with NAI on?)
UNBALANCED FIELD V1 WIND CORRECTION.
1. This shows the correction to be applied to the V1 value derived from the Integrated Performance
Columns.
2. IF TORA, TODA and ASDA (Accelerate Stop Distance Available) indicate a balanced field condition,
i.e. the values are the same, this correction need not apply.
COMMON MISCONCEPTIONS WHEN MAKING PERFORMANCE CARD CALCULATIONS.
1. For performance calculations the term 'light and variable' referring to wind velocity, assumes a 5
knot tailwind.
2. On the take-off performance card, for Zero Wind Weight, enter the maximum take-off weight for
the actual ambient or assumed temperature from the appropriate column of the Runway Analyses.
3. In general there is no headwind or tailwind correction for a climb limited take-off calculation.
However, until the performance card is changed to allow the check for the corresponding field limit
and a tailwind correction to be shown, then the tailwind correction is to be applied to the climb
limit.
4. Performance Decrement column, enter performance decrements if required for MEL/CDL items
APU ON and/or performance increments for Pack-Off take-off.
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10. THRUST SELECTION.
The fixed derate of TO1 or TO2 is considered a limitation for take-off. Thrust levers should not be
advanced further except in an emergency. A further thrust increase following an engine failure could
result in a loss of directional control.
Fixed derates are not to be used with Integrated Performance section of the runway analyser.
The use of the Assumed Temperature method of thrust reduction may be used in combination with
any of the fixed TO ratings with the following restrictions:
1. Not to be used with integrated performance section of runway analyser.
2. Wet runway prompt on the FMC take-off page must be used on wet runways.
3. No runway contamination is allowed.
4. The antiskid system must be operative.
5. All brakes must be operative.
6. Not to be used if windshear conditions are suspected.
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11. ALTERNATE EEC MODE OPERATION.
In order to simplify performance calculations when operating in the Alternate EEC Mode, Boeing has
provided an alternate method based on the more conservative derate of 10% TO1.
1. The antiskid system must be operative.
2. Operation on contaminated runways is prohibited.
3. Use of Packs Off integrated performance analyser is prohibited.
(WORK THROUGH AN EXAMPLE OF HOW TO CALCULATE v SPEEDS.)
OPERATING PROCEDURES:
1. Obtain take-off EPR (FPPM Section 4.5) for the Alternate Mode EEC. This is the only allowable
take-off thrust setting.
2. Use the TO1 runway analyser (Packs On balanced field) to obtain the limit weight.
3. Obtain the initial V speeds from TO1 Take-off speeds (FPPPM Section 1.3 dry runway, V speeds
Flaps 20') and your actual weight. This data is conservative for everything except Vmcg.
4. Check the initial V1 against full rated Vmcg (FPPM Section 1.2). Set V1=Vmcg if V1 is less than
Vmcg.
5. Check Vr against the new V1 from step 4 and Vr minimum (FPPM Section 1.2). If Vr is less than
either of these speeds, increase Vr to equal the larger of V1 or Vr minimum (Vr minimum takes Vmca
into account)
6. If Vr is increased in step 5, adjust V2 accordingly (FPPM Section 1.2)
7. These calculated speeds must be used in the FMS and entered on the take-off performance
calculation card.
NOTE: If operating at low weight/aft CG (Area F on the CG diagram), add fuel into the centre tank or
shift cargo to bring the CG out of area F (Refer to loadsheet, CG Envelope and Incremental Fuel
Indices-Centre Tank..........check this is available for Silkways). The centre tank fuel can be used after
take-off.
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12. ENROUTE OPERATION.
OPERATIONAL LIMITS DUE TO TERRAIN ENROUTE -WITH ONE ENGINE INOPERATIVE.
The aircraft gross weight at all points along the route shall be such that the one engine inoperative
service ceiling (This is the altitude with MCT set a climb gradient of 1.6% can be achieved) is 1000
feet higher than the terrain. This gross weight limitation must be met without fuel dumping.
Alternatively, the net flight path must permit the aircraft to continue flight from cruising altitude to
an aerodrome where landing can be made, the net flight path clearing vertically by at least 2000
feet, all terrain and obstructions along the route.
REMEMBER: Before shutting an engine down, consider operating it at reduced or idle thrust.
Generally when the flight has progressed 25%, continuation of flight to the destination is possible
with reserve fuel in place, with one engine inoperative.
Also, with AUTOSTART operative and an engine flamed out it is SILKWAY policy not to restart it if the
cause of the flameout cannot be determined.
It is desirable that the critical point(s) for start of drift down be given as a Pre-Determined Point
(PDP).
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13. LANDING DISTANCE.
The maximum landing weight at the estimated time of arrival at the destination aerodrome or any
alternate aerodrome shall allow for a full stop landing from 50 feet above the runway threshold.
1. For dry runways, within 60% of the landing distance available.
2. For wet or contaminated runway, the landing distance available is at least 115% of the
required landing distance for dry runway as determined above.
In calculating the above landing distance, the following factors must be accounted for:
1. The altitude of the aerodrome.
2. Actual headwind or tailwind component.
3. The runway slope in the direction of landing if greater than +/-2% (Limitation)
4. The aircraft will land on the most favourable runway, in still air.
5. The aircraft will land on the runway most likely assigned considering the probable wind
speed and direction and the ground handling characteristics.
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14. PERFORMANCE RULES OF THUMB.
1. Minimum achievable climb gradient on 4 engines is 7.3%
2. Best holding altitude is 25,000 feet (Max speed 265 knots IAS)
3. At maximum landing weight. Distance to reduce speed from 330 knots to Flap 10+10
knots is 14nm, and from 330 knots to 250 knots using speedbrakes only reduces the
‘clean’ distance by 3nms.
4. LRC is just an aerodynamic number affected by weight and altitude. However, ECON
CRZ considers the wind as well….LRC and Fixed Mach Number does not consider
wind.
5. Turbulence speed below 15,000 feet and below maximum landing weight, then 250
knots IAS is recommended.
6. Avoid using speedbrakes above Flap 10.
7. Maximum brake away thrust is 40% N1.
For information only.
Also when icing conditions are expected after landing, switch on the NAI at the end
of the landing checklist. It is not necessary to switch ON NAI when airborne if AUTO
is selected.
Smooth cancellation of reverse thrust at 70 knots to achieve reverse idle by 40
knots, with reverse cancelled and the engines in forward thrust by 20 knots; this is
the ideal scenario on a normal landing.
With pop up vibration annunciated on EICAS, NO crew action is necessary unless
other abnormal indications exist. Also the AVM is not valid at take-off thrust settings
or during power changes. The system is primarily for maintenance monitoring.
Ideally if the difference between the OFP and the loadsheet is greater than 5 tonnes,
then request a new OFP, unless the increase is due to extra fuel.
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15. PLEASE COMMENT ON ALL THE ABOVE, ALSO
LET ME KNOW YOUR CRITICISMS, AND WHAT
NEEDS TO BE ADDED OR DELETED.
THEN IT CAN BE SENT TO UNS TO FORMAT IN
AN ‘APPLE IPAD’ PRESENTATION.
MANY, MANY THANKS.
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