PPRuNe Forums - View Single Post - Qantas QF453 SYD-MEL Boeing 767 tailstrike on Mon 1-Feb-10
Old 4th Feb 2010, 03:08
  #32 (permalink)  
Keg

Nunc est bibendum
 
Join Date: Apr 1999
Location: Sydney, Australia
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If you start a rotation with the normal backpressure and the nose leaps up quicker than normal you "feel it" and reduce the backpressure until the rate is what you want.....yeah?
Yeah...and no. Sometimes the 'reduce the backpressure' is actually a 'forward check'. However, now you're in a situation where the 'normal' things like the 'normal' force you utilise, the 'normal' attitude you are for a given speed, etc is all different. You need to re-start the rate of change again and this time utilise a force that is 'less' than what was before and is decidely not normal. In these circumstances, like being in cloud, what you 'feel' may not be accurate.

I guess my point is that 'feeling' the rotate works under 'normal' circumstances. As soon as something is not normal (like the trim being out) then the subsequent feeling becomes more of a case of trial, error, and experience. EG: I recall flying a 767 more than a decade ago where the trim was so far out (rearward) that I needed forward pressure to keep the nose on the ground and maintained that forward pressure throughout the rotate until I could sort out the trim after becoming airborne. (Long boring story as to why and something that I won't go into on PPRUNE). Perhaps that makes the 'feel' case but given how different it felt to normal it could have easily resulted in a tail scrape.
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