Posted on 02/16/2009 5:00:40 AM PST by GBA
Q400 Pitched Up 31 Degrees Before Crash
The crew of the Bombardier Q400 that crashed in Buffalo on Thursday got a stall warning and the stick pusher engaged but still the aircraft pitched upward 31 degrees before turning almost 180 degrees and dropping onto a house in the Buffalo suburb of Clarence Center, near the outer marker for Buffalo Niagara International Airport.
The sequence of events, which included a 45-degree dive with a 106-degree right bank ended 26 seconds later in the fireball on the ground, killing 49 people on the plane and one on the ground, the owner of the house.
Although icing continues as a theme in the investigation, reporters were told at an NTSB press briefing on Sunday that the aircraft's anti-icing system had been on for most of the flight and, while both pilots discussed the "significant" icing their aircraft was experiencing, at no time did they use the "severe icing" descriptor that is the official notification of flight-threatening buildup.
"We don't know that it was severe icing," NTSB member Steve Chealander told reporters. "They [the crew] didn't say that it was severe icing....The weatherman didn't say that it was severe icing."
(Excerpt) Read more at avweb.com ...
stall
Classic ice-induced stall/spin. Rate of descent was 9,000 feet per minute.
That would seem to be the case.
Should the autopilot been engaged that close to the airport?
The last radar hit showed the aircraft flying at 100 knots and it lost 800 feet in five seconds. They did turn the autopilot off and went to full power just before the crash. Who knows...if they had been a lot higher, they might have recovered.
I was thinking stall/spin, or at least a stall leading to an incipient spin likely caused by ice building up on the tail feathers, which in turn caused an aft C of G which lead to the stall/spin. That would account for the orientation of the aircraft as it was found on the ground (pointing away from the destination airport) and why it appeared to have "pancaked" in. The situation was probably aggravated by the application of flaps on approach to landing, too.
I was talking to a retired United pilot. He said that that aircraft has really good anti-ice systems.
He said that flying on auto would mask the rate of build up and the severity, until the auto couldn’t handle the adjustments and would turn off, suddenly, and give the then too iced up aircraft back to the pilots, which by then would be too late. They were basically handed a turbo powered brick.
Thanks.
“Al Gore lied and people died!”
IIRC, the black box recordings have shown that they were on AUTOPILOT while encountering ‘significant icing’, which is against policy and FAA rules.
So this is being given to the world as a lesson.
One pilot, at the controls, loses both engines, and miraculously lands his plane in the Hudson, with no loss of life.
The other pilot, leaving his job to autopilot, not left with enough time to steer out of the way of the ground, losing all on board.
Perfect description of the events, as now known.
Maybe this is too simplistic, but I turn off my cruise control on my car the instant the [ICE] indicator starts flashing.
It was the weather, the plane simply froze in mid-flight, they will try to blame it on anything but that because they always fly in unsafe weather and there’s money to made folks, if you don’t see that you’re blind. The light mist in the air was perfect for freezing the plane up, the pilot even reported his windshield being iced over, I doubt at the end if could see a thing. I never fly, it’s unsafe, but for those that do I could see how you would never want to think that you take and land in unsafe positions, but you do, all the time. The true miracle is that there are not more crashes.
In defense of the aircrew....there was reason not to use the autopilot, no severe icing was reported, and the flight deck recorder indicates that the crew noted the ice, and didn’t mention the word severe...IMHO they were in compliance with the airline policy...
The aircraft stalled due to entering an unusual flight regime, that was never test flown....that of ice on the tail/elevators, concurrent with lowering of the flaps, at descent speed...
He's right.......I don't know the cockpit configuration in this aircraft. My time is mainly King Air 200, but the trim wheel is about 14 " around and while on auto pilot I would rest my right knee against it....if the trim ran I'd feel it, thus avoiding a overtrim situation, hopefully.
I won't second guess these two pilots, I just want to know why.
Just a reminder, there is almost always 3 times the ice on the tail, than on the wings in a T-Tailed turbo-prop.
What kind of idiot uses autopilot during icy weather? What do the pilot and co pilot have to do other than fly the plane? Ipod? Video games? Naptime?
It sounds a lot like the behavior of the jet that crashed into the Patomic in the 80s. It had icing on the wings and the ice reduced lift and increased drag. The plane pitches up to compensate and stalls and crashes.
Most precision (i.e. ILS) approaches on a large aircraft are initiated with the autopilot engaged. In icing, procedures differ from aircraft to aircraft. The problem with an autopilot ILS in icing is that, since an ILS has a glide slope and the airplane is supposed to be at a particular altitude on the way down its 3 degree angle descent, if the altitude varies, the autopilot engages the trim tabs and/or the elevator automatically to keep the airplane on glide slope. In icing, as the plane gets heavier and loses lift, the autopilot automatically tries to do this by increasing pitch/angle of attack. The engines also spool up more. But the weight of the ice and the changes it makes to the airfoil fights this automatic pitch change and suddenly you have exceeded the critical angle of attack/pitch and the wing stalls and bang! You are in a spin at low altitude and no chance to recover. In a spin the airplane is pointed almost straight down, as seen at the crash which was almost vertical descent, hitting just one house.
I did a little airline flying and a reason I left was because a scheduled airline flies in scary weather. That wasn't for me.
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