The other explanation is adrenalin. The "startle response" is quickly gaining currency as the biggest potential killer in line flying. With Colgan 3407 you have two tired pilots, one of whom is shocked into pulling up into a stall when the stall horn sounds. West Caribbean 708 had a Captain who was convinced he had a double flameout and concentrated on that, pulling up all the way into the ground. Birgenair 701 had a captain who focused on the initial overspeed warning to the exclusion of all else and pulled the aircraft into a stall.
Then you have success stories - US Airways 1548, BA038, Aloha 243 and United 232 as a few examples where in all cases the crew kept calm, overrode their internal panic switches and found a way to resolve things.
Whether you're flying, driving, doing your job or whatever - after doing it for some time things become routine - if something happens to break that routine then you have to keep your head about you and logically focus your way out of an event, but you've got millions of years of evolution behind the human brain which triggers a "fight or flight" response. Sometimes it works to the good and people have found almost superhuman resolve in themselves to get the job done, but sometimes it does not - people freeze or try random combinations of things they half-remembered in training or heard on the line with tragic results. It's all part of being human and training must address that.
Remember that the this was the PF's first day back on the job - he had just ended his holiday in Brazil and his wife was down the back - if there's a situation more conducive to be startled and try absolutely *anything* to keep that aircraft at the assigned cruise level, I can't think of it.
@Lyman - a phugoid cycle is something that happens over longer periods of time than the turbulence encounters the aircraft was experiencing. Remember JAL123 and UA232 - with dead flight surfaces the cycles happened over the course of about a minute and a half, so it was about 45 seconds of slow climbing followed by about 45 seconds of slow descent. The turbulence encounters and autoflight corrections we're talking about here were on the order of a few seconds at most. The pitch attitude was increasing at A/P disconnect as a result of one of those corrections, and stopped short of 4 degrees nose up because of the A/P disconnect. The elevators don't remain in the position they were in when A/P disconnects, they are set to match the last requested flight path angle, which was about 2-3 degrees nose up.
Last edited by DozyWannabe; 27th November 2011 at 18:04.