Originally Posted by Airclues
In April 1976 I was briefed on 747 airtest stalling by Ed Hartz, a Boeing test pilot. He warned that any rudder input, or engine asymmetry, at the point of the stall could cause a rapid roll rate which could not be corrected by aileron input.
Originally Posted by awblain
From the point that the aircraft comes into view, it rolls to the left - significantly, since the road bears round more gently to the right, and yet the aircraft still stays fixed with respect to the vehicle antenna - but I can't see any way from the video to say whether this is from an initial right roll or from the wings being level.
Watching the sequence of roll excursions, what struck me was the rapid yaw to starboard that initiated the nose falling through.
I suspect that the only means available of picking up the initial low left wing (to avoid rolling off to the left) was with a bit of rudder and that it was held a little too long.
Typically the ailerons/spoilers on swept wing aircraft are not particularly effective at stall angles of attack.(But if you cannot reduce your AOA, what do you have left to control roll?) I base this statement on significant exposure to low speed scissors fighter tactics wherein there is a significant advantage to being the
second one to fall out of the sky.
The problem with a massive aircraft is that it can be difficult to stop a yaw/pitch/roll rate once you have started such a rate, thus the caution about staying off the rudder in the first quote.
This is not to fault the crew's performance. Once the aircraft began to stall and drop wings, the likelihood of a successful recovery became remote. The only thing that then might have been hoped for was a much lower angle of descent to possibly regain flying speed. This would have required a much slower roll to a lesser bank angle. The finesse required to control the aircraft would require extreme luck and extensive experience maneuvering that type aircraft in the high AOA/post stall environment. Where are you going to get that experience?