1
04/02/2006RXCF
THE POWER�OF FLIGHTDERATE TAKE OFFDERATE TAKE OFF
(( ASSUMED TEMPERATURE METHOD )ASSUMED TEMPERATURE METHOD )
2
04/02/2006RXCF
THE POWER�OF FLIGHT
REDUCE TAKE OFF THRUST
3
04/02/2006RXCF
THE POWER�OF FLIGHT
WHY REDUCE TAKE OFF THRUST ?WHY REDUCE TAKE OFF THRUST ?
You will reduceTakeoff EGT
Substantial costs may be savedby extension of engine parts life time.
When REAL GW < MAX LIMITING GWMax Thrust is not any more necessary!
You will improveflight safety
4
04/02/2006RXCF
THE POWER�OF FLIGHT
You will improveflight safety
REDUCE TAKE OFF THRUST
IMPROVE ENGINE INTEGRITY BY REDUCTIONOF ENGINE DETERIORATION.
PROBABILITY OF ENGINE FAILURE
5
04/02/2006RXCF
THE POWER�OF FLIGHT
You will reduceTakeoff EGT
TAKE OFF IMPACTTAKE OFF IMPACTVsVs
FLIGHT COSTFLIGHT COST
Flight Leg
1
0.8
0.6
0.4
0.2
00.5 1.5 2.5 321
T/O
CLIMB
CRUISE
% of cost
6
04/02/2006RXCF
THE POWER�OF FLIGHT
Substantial costs may be savedby extension of engine parts life time.
EGT MARGIN WILLDECREASE SLOWLY KEEP SFC AT LOW RATE
TOTAL ENGINE PERFORMANCERETENTION WILL BE BETTER
LONGER ENGINE LIFE ANDINCREMENT OF SHOP VISIT RATE
REDUCTION OF MAINTENANCE COSTSREDUCTION OF MAINTENANCE COSTS( material, man power, services ... )( material, man power, services ... )
7
04/02/2006RXCF
THE POWER�OF FLIGHT
• RUNWAY (Length, Altitude, slope…)•TEMPERATURE, QNH, wind,…• FLAPS SETTING• OBSTACLES HEIGHT & DISTANCE• AIRPLANE CONDITION• RUNWAY CONDITION
For
At • MAX TAKEOFF THRUST SETTING
There’s 1 LIMITING GW
8
04/02/2006RXCF
THE POWER�OF FLIGHT
THRUSTT/Off GW
T°
Flat Rated T°
Real T°
TodayMax Thrust
TodayMax GWTodayReal GW
TodayReduced Thrust
Assumed T°
IF REAL GW < MAX LIMITING GW
A T° called “assumed T°” can be computed that would limit the performanceof the airplane to the real GW.
9
04/02/2006RXCF
THE POWER�OF FLIGHTHOUSTON,
We've got a problem here!
It looks like the assume temperaturewe took: – 55° wasn’t the right one !
Could you confirm ?!?
?!?
10
04/02/2006RXCF
THE POWER�OF FLIGHT
The accuracy of the OATis essential to optimize :
• TAKEOFF GROSS WEIGHT
• ASSUMED TEMPERATURE
11
04/02/2006RXCF
THE POWER�OF FLIGHT
DOES THE ASSUMED TEMPERATURE METHODALWAYS CONSERVATIVE ?
YES, because of T° effect on performance.
Air T° = 10°& TAS = 138.5 KtsV1 CAS = 140 Kts
The Speed used tocomply with the
performancecalculations!
The Speed you will have...
Assumed T° = 45°& TAS = 148.5 KtsV1 CAS = 140 Kts
Example:
12
04/02/2006RXCF
THE POWER�OF FLIGHT
Since the V1 are the same for both:
• The actual T°&• The assumed T°
The acceleration distances to V1 are always lessbecause the True Airspeed values are always lower.
TAS = CASTAS = CAS ++//-- 1% 1% 55°°c / Stdc / Std
++ if Tif T°° > Std> Std-- if Tif T°° < Std< Std
13
04/02/2006RXCF
THE POWER�OF FLIGHT
Distance from start of roll
V1 CAS = 140 Kts
V1 TAS = 138.5 Kts
Air TAir T°° = 10= 10°°cc
V1 CAS = 140 Kts
V1 TAS = 148.5 Kts
Air TAir T°° = 45= 45°°cc
AIRCRAFT PERFORMANCE MARGINAIRCRAFT PERFORMANCE MARGINWITH REDUCED TAKEOFF THRUSTWITH REDUCED TAKEOFF THRUSTIS ALWAYS CONSERVATIVE.IS ALWAYS CONSERVATIVE.
14
04/02/2006RXCF
THE POWER�OF FLIGHT
AIRCRAFT PERFORMANCE MARGINAIRCRAFT PERFORMANCE MARGINWITH REDUCED TAKEOFF THRUSTWITH REDUCED TAKEOFF THRUST
IS ALWAYS CONSERVATIVE.IS ALWAYS CONSERVATIVE.
You compute atYou compute at T = 45T = 45°°butbut
You fly atYou fly at T = 10T = 10°°
Distance from start of roll
Air T° = 45°cAir T
° = 10°cV1 CAS=
140 KtsV1 TAS = 138.5 Kts
V1 TAS = 148.5 Kts
15
04/02/2006RXCF
THE POWER�OF FLIGHT
TAKE OFF DATA ASSOCIATED WITHTAKE OFF DATA ASSOCIATED WITHA PARTICULAR AMBIENT TEMPERATUREA PARTICULAR AMBIENT TEMPERATURE
IS ALWAYS CONSERVATIVEIS ALWAYS CONSERVATIVEFOR ANY LOWER TEMPERATUREFOR ANY LOWER TEMPERATURE
WITHIN THRUST REDUCTION LIMIT.WITHIN THRUST REDUCTION LIMIT.
You know what ?
16
04/02/2006RXCF
THE POWER�OF FLIGHT
AIRLINEAIRLINEIS FULLY INVOLVED FORIS FULLY INVOLVED FORENGINE CHOICE ENGINE CHOICE ……
CREWSCREWSARE THE MAIN CONTRIBUTORS FORARE THE MAIN CONTRIBUTORS FORSAVING THE ENGINE !SAVING THE ENGINE !
17
04/02/2006RXCF
THE POWER�OF FLIGHT
THE ENDTHE END
THANKS FOR YOURTHANKS FOR YOURATTENTION !ATTENTION !