Reduced Thrust Examples
Airbus Model A340-311
And example of the conservatism inherent in the use of the assumed (flexible) temperature method of reduced thrust calculation.
Conditions A340-311
CFM56-5C2
Sea level
O A T = 15°C
12267ft runway
Actual airplane weight = 257 T permits assumed (flexible) temperature of 40°C
Parameters Actual temp is 15°C and assumed (flexible) temp is 40°C Actual temp is 40°C Margin
N1 (%) 90 90
V1 (KT IAS/TAS) 148 / 148 148 / 154 - 6 KTAS
VR (KT IAS/TAS) 155 / 155 155 / 162 - 7 KTAS
V2 (KT IAS/TAS) 161 / 162 161 / 168 - 7 KTAS
Thrust at V1, Lbs per engines 23.376 23.376 0 Lbs
Far field length (ft) 11358 12267 909 ft
Accelerate-stop distance (engine-out) ---ft 11174 12175 1001 ft
Accelerate-go distance (engine-out) ---ft 11322 12175 853 ft
Accelerate-go distance (all-engine) ---ft 11358 12267 909 ft
Second segment gradient % 3 3 0.0 %
Second segment rate of climb ---ft per minute 490 509 - 19 Fpm
Reduced Thrust Examples
Airbus Model A340-642
And example of the conservatism inherent in the use of the assumed (flexible) temperature method of reduced thrust calculation.
Conditions A340-642 RR TRENT556 Sea level OAT = 15°C 11558ft runway
Actual airplane weight = 368t permits assumed (flexible) temperature of 40°C
PARAMETERS Actual temp is 15°CFLEX temp is 40°C Actual tempis 40°C Margin
V1 (kt IAS/TAS) 155.6 / 156.7 155.6 / 163.4 - 6.7 kt TAS
EPR at V1 1.285 1.285 0
Thrust at V1 (lbs/eng) 40405 40405 0 lbs
VR (kt IAS/TAS) 165.7 / 167.2 165.7 / 174.3 - 7.1 kt TAS
V2 at 35ft (kt IAS/TAS) 178.5 / 177.5 178.5 / 185.1 - 7.6 kt TAS
Far field length (ft) 10719 11558 839 ft
Accelerate-stop distance (one engine out) (ft) 10020 10942 922 ft
Accelerate-go distance (one engine out) (ft) 10305 11115 810 ft
Accelerate-go distance (all engines) (ft) 10719 11558 839 ft
Second segment gradient (%) 4.83 4.83 0%
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