The Safety Board considered why the first officer responded differently to the second wake turbulence encounter than he did to the first encounter. One possibility is the difference in the bank angle at the beginning of the two encounters. For the first encounter, the airplane was approximately wings level. Before the second encounter, the airplane was already in a 23º left bank, and, according to the Board’s simulations, the rolling moment generated by the second wake would have acted to roll the airplane (in the absence of countering control inputs) about 10º farther to the left and would have resulted in no significant yaw. However, if the first officer sensed a roll acceleration to the left while already in a left bank, he may have been prompted to react with a more aggressive control response.
The Safety Board emphasizes that the second wake encounter did not place flight 587 in an upset condition, and the airplane’s response to the wake did not indicate that an upset was imminent.197 Therefore, the Safety Board concludes that the first officer’s initial control wheel input in response to the second wake turbulence encounter was too aggressive, and his initial rudder pedal input response was unnecessary to control the airplane.
From what I recall and, I think, is again verified by reviewing the NTSB-sponsored creation of the animation (and a big thanks to SMOC for finding and posting it) is that the 23° left bank that existed at the initiation of the 2nd wake encounter seems (to me at least) to remain essentially constant until the very rapid right control wheel and right rudder applications. I fully recognize that this is simply an animation of the FDR traces – and that the FDR information was (as I recall) produced after being “filtered” from the digital recording to be able to print it as an analog trace – and I would feel a lot more comfortable with a “discussion” of what could have happened to generate the observed control application, rather than have someone simply say that “the F/O sensed a roll acceleration to the left.”
Of course, I certainly entertain the logic of a momentary on-set acceleration being immediately noticed PRIOR to the airplane actually beginning to move (and thereby NOT recorded on the FDR) and have that on-set acceleration recognition prompt the pilot to apply substantial right control wheel deflection simultaneously with substantial right rudder input – BEFORE that acceleration actually produced an FDR-recorded rolling movement. In fact, I think that such razor-thin timing is very likely what actually happened … but I also think that would result from one of only two sets of circumstances:
First – this pilot was always reacting almost before anyone else recognized the need for any reaction – and in my experience that almost never occurs; and
Second – the F/O was bordering on or had reached a panicked mental state.
Unfortunately,
THAT I have seen … and believe me, if you’ve ever seen it, you will always remember it! In fact, I think it is entirely possible that the Captain had either noticed or suspicioned something being inconsistent with what he had previously seen from that F/O and that was why he asked “Are you all right?” pretty much AS the F/O applied those extreme control inputs and said “Let’s go for power please.” I think it’s also important to note that the F/O comment on power was annotated as being spoken in “a strained voice” – also a reaction to panic.
Apparently, the F/O continued to apply these substantial control inputs – very likely after the first such input, were made thinking they were necessary to counter what the airplane was doing … and the airplane was merely doing what it was commanded to do by the F/O control inputs.
Again, I take no particular joy in making these comments – but I think it’s a logical way to make all the pieces of the facts make some kind of sense.
OK – I’m ready for the critiques.