The cause of the Continental Commuter crash (Colgan Air 3407) in Buffalo likely due to tail ice

Posted on 15. Feb, 2009 by in Featured

The NTSB initial brief made it very apparent to me that the cause of the crash of Colgan Air 3407 was ice accumulation on the tail that then caused a severe nose pitch down.
“One minute before the recordings ended, the crew extended the landing gear, and 20 seconds after that, ‘flaps 15’ was selected. Within 15 seconds of the flaps command, the flight director indicated a “series of severe pitch and roll excursions.” Shortly thereafter — and just before the end of the recording — the crew “attempted to raise the landing gear and the flaps,” said Chealander.”
Ice build up on the leading edge of the tail causes aerodynamic forces to actually move the flight controls and pitch the nose of the aircraft down. The force necessary to counter it can be up to 170 pounds according to NASA. Below is a series of NASA videos on tail ice. I think EVERY pilot should watch this in its entirety.

As the video details the auto pilot being on can mask the indications of tail ice. The probable sequence of events is below:
-The aircraft arrives at the marker.
-The crew configures the Q-400 for final approach by extending the gear and then flaps.
-Normally a crew will kick off the auto pilot at this point.
-Due to the change in airflow detailed in the NASA video the nose pitches over with no warning to the crew.
-Severe pitch and roll oscillations occur. PIO (pilot induced oscillations) likely caused the pitch excursions both nose up and down. As detailed by NASA the yoke would be very light in forward motion and very heavy in aft movement leading to PIO. The roll oscillations were likely caused by the nose pitching up causing the ice contaminated wing to stall; with wing rock as a result.
-The crew attempts to counter by initiating a go around and raising the gear and flaps as they fought for control.
-They ran out of altitude before they could regain control.

This series of videos should be mandatory viewing for all pilots. You can be in icing in a heart beat, with very little visual warning especially at night.

NASA has done excellent research for this video. The presentation is informative and goes easy on the “tech-speak”.

No Responses to “The cause of the Continental Commuter crash (Colgan Air 3407) in Buffalo likely due to tail ice”

  1. Rick 15 February 2009 at 16:53 #

    Now we’re hearing the auto-pilot was engaged when the dash8 crashed, which is a violation of company policy. I’m not familiar with the FAR regs on that. Since the guy pancaked in, it seems his air speed must have unbelievably low. It’s difficult for me to believe this man didn’t want to “feel” his airplane in those conditions. Rick

  2. Chip 15 February 2009 at 18:49 #

    Yes it is surprising. I suspect that it happened very fast and it was late. I don’t know what the crews schedule was or their rest prior. But I suspect that will be looked at closely. I can also tell you from experience that a departure can be very violent and the onset is eye watering.

    When I was an F-4 instructor pilot for VX-30 I would brief the quirk the Phantom had at high alpha (angle of attack). You could not use stick to turn with the AOA above 15 units. It would cause an adverse yaw departure. Invaribly they would put in lateral stick in the demonstration, the aircraft would go from 90 degree angle of bank to the right and snap to 60-90 degrees of left bank. Normally accompanied by a “holy sh….” I’d watch the stick move and hold on, the onset was so fast these experienced test pilots didn’t feel it coming.

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