How to determine the engine failure speed Vef
 

Now, i am studying the FTE course. When i read the take off and landing performance note, i do not understand the engine failure speed well. Dose it determine by the designer, how to select, and what test should be done for it?

I think you should ask for your money back?:cool:

...................Just that I agree with BOAC ;)

fanx,

Vef is not a compliance speed itself as such.

It is simply the speed at which you fail the engine, and which subsequently (after pilot reaction time) results in, for example, a Vmcg which complies with the requirements.

Hello Fanxiyi,

Dont worry about BOAC,you can get his expertise with the search option when he is in a non responsive mood:E

VEF is a speed at which the engine is failed during calculation of take off distance by the manufacturer.
V1 is relevant to pilot as it is the speed at which the first action must have been taken (ie thrust idle) during a reject call.
The AFM has some extra reaction time (2secs)as during test,the pilots know they will reject.
V1 is therefore a speed of first action,to achieve this VEF is normally 1sec before V1 and includes speed increase from VEF.

Tests are done for VMU and VMCG/A for controllability checks during certification.