Speed Relationships Flashcards
VEf to V1
Velocity engine failure considered to occur one second before the one
V1=VEf + 1 second
V1 to Vr
May not be greater than rotate, rotate may not be less than v1
V1 to Vef speed relationship
may not be less than the speed at which the engine fails + the speed gained until the first action is taken to stop the aircraft, pilot must take action prior to V1.
Cannot be so close to engine failure velocity that by the time the pilot recognises a failure, V1 has already been exceeded.
Pilot basically has one second or less to recognise failure and take action
V1 to Vmcg
V1 may not be less than vmcg as enough speed must be present in order to control the aircraft directionally, on the ground using control surfaces only.. following an engine failure and with remaining engine at maximum thrust
Remember speed is too great for use of tiller, so directional control must be possible on the ground
V1 to Vmbe
V1 may not be greater than vmbe , so that if take off is rejected the brakes are able to bring the aircraft to a stop within accelerate stop distance available.
If V1 was greater than Vmbe, there would be too much energy for the brakes to stop the aircraft before end of ASDA
Vr to Vmca
Vr 1.05 times Vmca.
If takeoff is continued pilot can maintain directional control in the air
V2 to vmca
1.1 times Vmca, also ensures directional control can be maintained following an engine failure and takeoff is continued.
V2 relationship to stall speed
1.2× defined stall speed, Vs.
Relationship between V2 and speed gained after Vr
May not be less than the speed at rotation plus the speed gained to 35 ft screen height, this ensures that the aircraft is not required to reduce the airspeed in order to achieve the screen height of 35ft.
Vmca relationship to stall speed
May not be greater than 1.2 times the stall speed determined at maximum takeoff weight, ensures aircraft is not required to maintain too high an airspeed to maintain directional control in the air.
Imagine Vmca at 1.4× stall speed, speed required in order to maintain control in the air would be too high, so directional control would be impossible until this speed.
