1. Firstly, however illogical it may seem, for flight crew to pull back on the stick at shaker activation is not unknown; depending on the system design, when the AP disconnects it may release the stick forward a little, and the crew may tend to "snatch" back at the stick, since it looks like a sudden and unwanted movement.
I don't disagree with that general statement but, due to this design (if I understand it correctly) that is unlikely to happen if the aircraft is stable. I do think, in this scenario, there would be a sudden and unwanted nose up movement following the application of full power. Not because the elevator did anything but because full power was applied and the elevator remained in the same position. If power had not been applied the nose would drop because at the decreasing speed there is not enough up elevator to keep it from doing that. The only reason this elevator was deflected, IMO, was because alt hold was engaged and there was insufficient power to maintain a constant speed.
2. Secondly, be vary careful in making assumptions as to how the trim system will be affecting the control system dynamics. With AP on, the trim is acting to relieve the AP servo (assumption based on other designs) and so when the AP disconnects you should NOT get a big input from the trim - it should be more or less aligned with the current elevator position. I thought there was a docket item on the control system (in the presentations on day 1 of the hearing) but I cant find it right now
Your warning is accepted. I acknowledge that I am making some assumptions and they may be unwarranted.
Perhaps I'm not articulating correctly and making myself clear. I agree as to why the trim is acting with AP engaged. If there was enough power to maintain constant airspeed the AP servos would not be under duress and trim would not change. When the AP disconnects - absolutely nothing happens as a result of previously input trim - unless speed is increased or a large change in power is added. In other words the elevator is not going to change its physical position because the AP disconnected - it will stay where it was. If no power is added, the nose will drop and speed will increase slowly. If only enough power is added to hold the speed at the time of AP disconnect - the aircraft will fly level as it did with the AP engaged and speed will neither increase or decrease. (In stable air) There is nothing to upset the balance (between power required and power available).
In the scenario I envision the pitch up is caused by the addition of max power. The already deflected elevator, which has not changed its positon, operates to increase the rate of pitch change. If it happens fast enough, the additional power can't increase the speed fast enough - and therefore drag and AOA increase rapidly. If the change is big enough the wing will stall.
Take a look at this incident report.
http://www.aaib.gov.uk/cms_resources...9%20G-THOF.pdf
Although the situation is somewhat different and the aircraft design is different (the Boeing uses a trimmable stabilizer - the Dash a trimmable elevator) the concepts involved is similar.
Once the shaker went off in Colgan 3407 the recovery was intiated by the application of full power. Regardless of elevator trim this was going to result in very significant pitch up moment. This is due to the high power output of which these engines are capable. [Keep in mind that the aircraft was actually considerably above its actual stall speed and below its stall AOA. The only reason the shaker activated at that point was because the REF SPEED switch had been activated - and there really wasn't any significant ice.] This fact, I believe, helped to increase the rate of pitch up. The trimmed up displaced elevator simply aided in the pitch up rate.
Without immediate and heavy nose down input from the PF it is no surprise that the pitch went beyond +20 in a couple of seconds and continued in that direction for another +10 deg. Of course I could be dead wrong but I don't think the PF had to "pull" on the column at all to get that high pitch attitude. There appeared to be a pulling force registered by the tranducers because the elevator was already trimmed close to maximum nose up. When the AP "released" the column moved to the elevator position (in theory). I would sure like to see that tested during the investigation.
With nearly 10K SHP available, this airplane should have easily been able to fly out of this situation. The only thing the PF had to do was push as hard as he could (and perhaps trim out some of the back pressure).
Note that once the pitch reached +20 deg the aircraft began to roll hard left. Most probably that was initiated by the high torque moment generated by those huge propellers at max power. Attempts to counter the roll didn't help the PF to realize the need for agressive nose down control pressure. From my perspective once the pitch up reached +25 this was no longer a stall warning recovery drill, it was an upset recovery drill.
I have no idea if the Q-400 QRH includes any procedure for upset recovery but even if it does, I seriously doubt that either of these pilots had received any upset recovery training. Again I could be dead wrong but I doubt either of them had ever seen a pitch attitude above +25 deg.
What their airplane was doing just didn't relate to anything they had done before and it did not compute mentally. If ever it did during the remainder of the event, it was already too far gone to effect a recovery.
I know nothing of Colgan's training procedures but if they are anything like those of the regional airlines I have witnessed, they did not include anything close to what happened even in discussion, let alone in practice. Most probably it was just FAA minimums and that's it.
One also has to wonder how the experience levels of the training captains might compare to that of the Pilot Flying the accident aircraft. You can't teach what you don't know yourself.
In one regional carrier that I happen to be familiar with, when they first introduced jets no one in the training department had ever flown a jet. Those line pilots with extensive jet experience were not used - because their politics were not compatible with management's. They were 'union members' and that made them anathema to the management culture. The chief pilots also had no hands on experience with swept wing jet aircraft. The final frosting on the cake -- the POI, responsible for oversight, had never flown any airplane larger than a twin Comanche. The Feds sent him up to Canada for a quickie course and type rating and a month later he was back as the 'resident expert' - making critical decisions about things that he didn't fully understand himself. In spite of it they survived, but it was far more luck than brains.
When pilots have to work in that type of environment I have a very hard time blaming then for the mistakes they make. It is also an injustice to young airmen who are intelligent, eager and willing to learn but just don't get the support that is required. In a year or two they upgrade to the left seat and survive by the grace of God. Sometimes they don't.
From a Piper to the right seat of a Q-400 or an RJ is a long way to go with very little training and sparce experience. Especially so when you sit next to a "Captain" with only one year's exposure to a Saab or some other light turboprop.