I don't know why the gurus have not yet commented, and if you will forgive my lack of recent contact with the subject I will have a go.
Clearly, up to now, we have been talking about non-scheduled performance aircraft. Transport aircraft certified under JAR 25 must be able to sustain a failure of the critical engine at any stage of flight and recover safely on the remaining engines. Without the tits and knobs this means that once you have passed Vmcg on takeoff you can continue if you have enough runway available, and when you lift off you must be over Vmca. For certification Vmca must therefore be less than 1.2Vstall, and by the time you have passed Vr and unstuck you will be flying faster than this.
Coming back, you have to stay above Vmcl in the landing configuration until committed to the flare. Vmcl is just as low as Vmca, so usually is lower than Vref, and all is ok. In some extra critical conditions - two of four out on the same side - Vmcl may be higher than Vref, in which case you have to fly Vmcl right down to the flare and accept the fast landing.
On top of this you have to consider the power loss, and how it affects your decision, but that is another subject.
Hope I got that right!
Dick W
Last edited by Dick Whittingham; 4th Jul 2003 at 03:29.