Critical engine failure and crosswind

[tornadoflyer]

Hi,

I have a question regarding critical engine failure and crosswind. Assuming that the number one engines fails, due to increased drag the aircraft will yaw to the left. What kind of crosswind will further deteriorate the situation? I actually thought that left crosswind would be most disadvantageous because the aircraft tends to weathervane into the wind, consequently letting the aircraft further yaw to the left. In one of the technical aviation books I read that in this case, right crosswind would be better because it has a restoring effect.
Thanks in advance for any inputs regarding this subject.

[john_tullamarine]

Suggest you run a search on Vmcg and you will get plenty of stories ..

Basics ..

(a) Vmcg determined for nil wind under current standards

(b) wind from the side with the failure is destabilising and makes things worse. Typically the AFM Vmcg will increase by 0.5 to something in excess of 1.0 kt/kt of crosswind depending on the particular aircraft

(c) typically only really a concern for very light ferries or positioning flights where the takeoff might be predicated on minimum speed schedules (ie V1 min)

As an aside (and I presume that your No 1 failure means LH outer) the yawing moment is not so much due to a change in drag (although that may be a component) but due to the spanwise thrust asymmetry considering LH and RH sets of engines.

Your comments on wind are both correct .. for a No 1 failure, a left crosswind causes the situation to be more critical while a right crosswind improves the situation ..

[Capt Claret]

You're talking apples and oranges.

You're question asks what will exacerbate the yawing of a number one engine failure, x/wind from the left or right. Your reasoning for assuming a x/wind from the left is correct.

In trying to expand on your question, you're approaching it from the other angle, that of minimising the yawing effect, and the technichal publication you cite is correct.

[tornadoflyer]

Thank you both for your comments. I have to revise my question because the book states that left crosswind would be better and act as a restoring force and that was initially what I did not understand as both of your answers did actually confirm my thoughts. The same book also says that in an engine failure case in a max crosswind condition between V1 and Vr, the upwind engine would be more favourable to lose. Now, I am a little bit confused. Any inputs are greatly appreciated.

[john_tullamarine]

.. think I'll take the alternative ..

Consider ..

(a) LH motor quits

(b) aircraft yaws to the LEFT

(c) add left crosswind and the left yaw is magnified ..

(d) add right crosswind and the left yaw is reduced ...

(assuming normal stability characteristics ...)

Suggest that you throw the book which you are reading in the corner and cover it up with other rubbish ..


... then, again ... if you can avoid rolling yourself into a ball ... once you have done a full 180 and somehow are now going in the opposite direction ... maybe ..