OEI - Why does the Balance Ball show a slip?

[john_tullamarine]

ah .. the discussion is livening up a bit ...

For the benefit of any newchums ..

(a) it is very important to keep in mind that Vmc/Vmca is a certification animal and not a great deal of use in the real world (unless you get down too close to it .. in which case it becomes a major driver to pilot strategy)

(b) it is not feasible to play with the AFM Vmc in the real world due to thrust variations

(c) if the pilot finds him/herself at or close to Vmc, then the bank into the live engine becomes a necessity. Unless you have documented advice to the contrary, it is safe to presume that the AFM Vmc data is based on the 5 degree-into-the-live-engine trick.

(d) be VERY wary of bank near Vmc .. the real world Vmc is VERY sensitive to, and dependent on, the actual bank angle. Acknowledging the limitations of flight simulators, it is always an interesting exercise to give the student a Vmc limiting takeoff failure ... if the bank is not well controlled (and this usually means aggressively ..) the aircraft rapidly banks into the dead engine .. the real world Vmc goes up past the actual speed .. and the outcome is foregone. A bit of practice corrects the technique errors but the lesson for the student is driven home strongly and very convincingly.

... and

(e) thanks to B for his picture-worth-a-thousand-words .....'

(f) as Dick suggests, for normal ops OEI, it is conventional and convenient to fly wings level and take a small performance hit due to whatever sideslip exists ... but note (d)

(g) having had a lengthy involvement in pilot theory training in years gone by .. I have to echo Dick's sentiments about pass versus education. If the knowledge is there, then the pass is a small additional effort to come to grips with the idiosyncratic nature of examinations .. but if the training has only concentrated on past papers, etc., then the pass might be there, but there is no depth to the knowledge ... the Industry and the examiners really ought to question what it is that the examinations are trying to do.