Stardust,
Can't speak specifically to the 757 ... perhaps Mutt can when he sees your post ... however, the following general principles apply
(a) crosswind will, if the failure is on the windward side, add to the undesired yawing moment and increase the aircraft's lateral deviation from centreline .. not good. Conversely, if the failure is on the leeward side, things improve ... problem is you can't bet on the situation.
(b) FAR requirements adopt a nil wind Vmcg.
(c) as the V1 reduces toward, and below, Vmcg in nil wind conditions at critical thrust levels (normally near SL, max rated with a high thrust tolerance motor, aft cg, etc ..) the observed centreline deviations increase rapidly and significantly until a point where the aircraft track is uncontrollable and runway departure occurs. This is a REAL, not imagined, scenario and the onset of problems is surprisingly rapid .. ie occurs in a small speed spread.
In a crosswind situation, the notional effect is for the real Vmcg to increase. Boeing would have this data and it may appear in the relevant Boeing Performance Engineers' Manual. Such data as I am aware of (but not specifically for the 757) suggests that this increase is in the typical range of 50% to something in excess of 100% of the crosswind, depending on the particular aircraft Type.
I wouldn't like to be on the aircraft in the circumstances you describe with a decent crosswind and a Vmcg failure .... interesting to watch from the sidelines, though ...
Last edited by john_tullamarine; 9th July 2002 at 21:33.