Colgan 3407 Down in Buffalo

[bailout]

As soon as the flaps extend the tailplane stalls and the autopilot disconnects. At the same time a wing drops – due to ice-induced roll that the autopilot was compensating for. The nose pitches up (due to the nose up trim input by the auto pilot). The captain initially counters the pitch-up with nose-down pressure, which agravates the tail stall.

The captain quickly recognizes the tail plane stall, commands “flaps up” and pulls on the yoke. At the same time he is countering the roll with extreme opposite aileron.

Now the wing stalls – shaker activates followed immediately by pusher. [Remember – attitude and AOA are two different things – a wing stall can occur at any attitude or airspeed.]. Pusher activation causes the tail to stall again. Recovery by nose up control input is attempted a second time, the wing stalls again and the pusher activates for the second time. Pitch and roll excursions are severe. In the process direction has changed by close to 180 deg. By this time 1200 ft of altitude has been lost – the aircraft drops off radar. Pitch attitude is 30 – 40 deg. Nose down.

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Understanding question: If the tail stalled first, when the AP disconnected, why would it pitch nose up? Everything Ive seen on the subject says that nose would pitch down. I understand the trim issue, but it was keeping the airplane level with the weight of the ice so when the AP disconnects, wouldnt the tail stall cause the nose to drop first?

 

[satpak77]

I too am wondering why it would pitch up first.

I think there is more to the story than just "ice brought them down"

also, see these pics, if they landed bottom first (for lack of a better term), why is the gear so pristine?

I believe they landed inverted, flat, facing the other direction

http://www.cnn.com/2009/US/02/15/buffalo.plane.crash/index.html#cnnSTCPhoto

 

[belchfire]

Gear isn't pristine. Forward strut is bent...

 

[satpak77]

Gear isn't pristine. Forward strut is bent...

well its pretty darn pristine if we are under the belief they landed flat/pancaked in right-side up. Remember only one house was hit and a very localized area exists.

Maybe the strut was bent due to vertical impact forces

yes yes this is speculation and I do not claim to be correct, however it is worthy of discussion

 

[BVT94]

Do the flaps meet up to the ailerons on the Q400?

 

[ksu_aviator]

The gear is probably sturdier, more dense and they hit at 31 degrees nose down.

The data all points to a sudden pitch up resulting in a stall and probably a spin. The question is why?

 

[belchfire]

I could only see one of the main gear. My suspicion is that the one in the picture was sheared away from the wreckage and fire damaged areas by contact with the house, hence no dirt or debris on it.

 

[TOOL CRIB]

I thought the gear was on the way back up when they hit?

 

[172driver]

AP on, power back, configuring, slowing, anticipating GS intercept. GS doesn't capture or hasn't yet, deck angle rising, crew realizes they're getting slow, adds power but does not disengage AP and lower nose, stall, spin?

I hope there's more to the story.

 

[Singlecoil]

I wonder if the icing simply served to divert their attention the way it has all of us.
Power levers at idle, aircraft slowing and being configured on speed. Autopilot keeps rolling the trim back to maintain altitude as the aircraft slows until stick shaker. Stick shaker occurs, full power is applied, autopilot kicks off, nose rises steeply as the trim is all the way back with full power, stall occurs, stick pusher shoves the nose down hard.

There have been several instances when I have been the non-flying pilot and thought the autopilot was off because the flying pilot had his hands completely on the controls and was allowing his hands to be moved by them. I could see the FO in this case not being aware the autopilot was on as well.