Colgan 3407 Down in Buffalo

[q100]

This is an intentional duplicate post. I put it in the wrong thread before.


Read this article

http://online.wsj.com/article/SB123492905826906821.html

This is an excerpt of the first two paragraphs. Reportedly, the source is 'the investigators' (NTSB)

"Investigators examining last week's Continental Connection plane crash have gathered evidence that pilot commands -- not a buildup of ice on the wings and tail -- likely initiated the fatal dive of the twin-engine Bombardier Q400 into a neighborhood six miles short of the Buffalo, N.Y., airport, according to people familiar with the situation.

The commuter plane slowed to an unsafe speed as it approached the airport, causing an automatic stall warning, these people said. The pilot pulled back sharply on the plane's controls and added power instead of following the proper procedure of pushing forward to lower the plane's nose to regain speed, they said. He held the controls there, locking the airplane into a deadly stall, they added."

Now look closely at the second paragraph.

My opinion: A) The first sentence (2nd paragraph) is plausible. B) I do not believe the second sentence. I think the NTSB's assumption is wrong.

This is telling us that when the shaker activated and the autopilot disconnected - the pilot pulled back hard on the yoke, added power and then held the back pressure throughout.

To put it simply, I think that's unadulterated BS!

I believe the NTSB (at present) is misinterpreting the pitch -up data (which aggravated the stall) as being caused by or resulting from incorrect pilot input.

If true this is damning.

It is also the complete opposite of training and I just don't believe it.

In critical situations pilots (initially) automatically react in accordance with their training. When the shaker goes off - you push not pull.

I think that whatever 'investigator' said this is overlooking the nose-up trim induced by the autopilot prior to the disconnect.

It may turn out that mistakes were made by the crew prior to the upset - but I just don't buy that one.

For now I'll stick to my theory of elevator trim as the cause of the pitch up and the progression from shaker to pusher - the initial stall of the wing.

After the pusher took effect and pitched the nose down - then yes - the pilot applied back pressure. But not before.

These folks were flying on instruments. You just can't convince me that any pilot who looks at the ADI and sees a servere pitch-up is going to try to correct it by pulling on the yoke - no matter what noise the shaker might be making.

If this really came from an investigator - then they're doing a lot more "speculating" than anyone in this thread.

Actually, and I've been concerned about this for years, each of the airlines I've been at (including 2 Dash8 operators) trains stall recoveries with the emphasis on holding attitude and powering out. The reduction in angle of attack comes from increased forward speed, not from change in pitch. Completely bass-ackward from the primary flight training we all received where reducing pitch attitude is the first step to recovery. Now I know the theory behind the "airline method" is that the recovery is from the first indications of a stall, but...

The first indication of a stall is usually the stick SHAKER. The pusher might never be experienced in a training environment, unless recovery is slow/delayed. To my knowlege - correct me if wrong - SAAB 340s do not have a stick pusher. It may very well be that the crew had never encountered one in action before. I'm speculating here - only those familiar with Colgan's Q400 program can say if this would have been the case or not.

To go one step further, lets say the crew of 3407 was attempting this maneuver against a stick pusher. To maintain pitch attitude and altitude would require enough back pressure to overcome the pusher. When it breaks away, all of a sudden there's 80 pounds or so of back pressure on the yoke. That could lead, I would think, to a 30 degree pitch up and an accelerated stall rather easily.

Pure speculation I know. But, if it turns out that this was just a case of a tired and distracted (by ice, new aircraft type, unfamiliar airport, high workload approach, whatever) crew getting too slow and then attempting to recover from the stall indications as per simulator training, then I think we pilots need to take a long hard look at stall recovery training and return the emphasis to the most important thing in any stall recovery, reducing the angle of attack.

As a former Dash8 100 driver, can any of you Q400 folks tell me if your stall recovery training in type involved the pusher? Or was it as described above?

Q.

PS: I am not blaming the crew - I don't know the facts of what happened. But if the scenario I laid out did actually take place, I think we have an industrywide need to re-evaluate stall recovery training.

 

[WSurf]

Actually, and I've been concerned about this for years, each of the airlines I've been at (including 2 Dash8 operators) trains stall recoveries with the emphasis on holding attitude and powering out. The reduction in angle of attack comes from increased forward speed, not from change in pitch. Completely bass-ackward from the primary flight training we all received where reducing pitch attitude is the first step to recovery. Now I know the theory behind the "airline method" is that the recovery is from the first indications of a stall, but...

Its because you are training in a 121 Commerical environment. You're not doing full stalls on the commerical level like you did in the underpowered Piper or Cessna.
Its the first indication of stall, the shaker or buffet you are instructed to recover then.
Added power and either leveling your pitch or maybe lowering a bit should get you out of the impending stall easily.

So no, the 'airline method' is not a$$ backwards.

 

[BirdCatcher]

To my knowlege - correct me if wrong - SAAB 340s do not have a stick pusher.

Saab has a stick pusher

 

[q100]

To my knowlege - correct me if wrong - SAAB 340s do not have a stick pusher.

Saab has a stick pusher

thx - next question: would it ever be encountered in training?

 

[LJ45]

from the WSJ:

According to the plane's flight recorders, Flight 3407's descent into Buffalo was routine until roughly a minute before impact, when the crew lowered the landing gear, followed by the command to extend the wing flaps, which enable the plane to fly at slower speeds.
Almost immediately, these people say, the plane's air speed slowed rapidly, causing a stall-warning device known as a "stick-shaker" to cause the pilots' control column to vibrate. This was followed by a "stick-pusher," which automatically forces the stick forward.
At this point, the captain appears to have pulled back with enough force to overpower the stick-pusher and shoved the throttles to full power, according to people familiar with the matter. Safety board officials said the nose pitched up to a 31-degree angle. Already at a dangerously low speed, the wings immediately stopped generating lift. The plane whipped to the left and then entered a steep right turn, losing 800 feet of altitude in less than five seconds. At one point the right wing was perpendicular to the ground, according to information taken from the flight data recorder.
The pilots continued to fight with the controls almost all the way to the ground, and in the final moments, "it appeared that they were beginning to make headway when they ran out of altitude," said one person who looked at the data.

 

[Stifler's Mom]

I was reading an airticle on CNN.com yesterday, and in the article it mentioned that the airspeed was at 100-110 kts just before the crash. Not sure if they meant during the impact, or just before the possible stall. When I went looking for the article again, it was gone.

That speed seemed very slow, and I wanted to verify what I had read. Anybody else see that?

 

[Andy Neill]

One issue I have not heard addressed yet is the probability of an accelerated stall. At some point in the event, 2 g's were experienced. That would have the effect of an increase of stall speed by 41%. A plane flown on approach at 1.3 Vso that then pulls 2g's will stall. If the plane was flying below 1.3 Vso (as several have implied) that would stall it with less of a g pull.

 

[LJ45]

One issue I have not heard addressed yet is the probability of an accelerated stall. At some point in the event, 2 g's were experienced. That would have the effect of an increase of stall speed by 41%. A plane flown on approach at 1.3 Vso that then pulls 2g's will stall. If the plane was flying below 1.3 Vso (as several have implied) that would stall it with less of a g pull.

They pitched up to 31 degrees quickly, either it stalled during that pitch up or pulled g's ??

 

[q100]

Its because you are training in a 121 Commerical environment. You're not doing full stalls on the commerical level like you did in the underpowered Piper or Cessna.
Its the first indication of stall, the shaker or buffet you are instructed to recover then.
Added power and either leveling your pitch or maybe lowering a bit should get you out of the impending stall easily.

So no, the 'airline method' is not a$$ backwards.

Thanks for reply - I actually am aware of all you are saying. 5000+ hours on Dash8 100s....

It's not bass ackwards in general, but it is bass ackwards from the way we learn stall recoveries from day one of student pilot training, which is first and foremost reduce the angle of attack by reducing pitch.

And my point was this - in trying to maintain pitch attitude against a pusher, a pilot could conceivably use enough force to over-ride the pusher, at which time 80# of backpressure would be transmitted to the elevator un-opposed, with a pretty rapid pitch up almost inevitable.

Also, have any of us driven an airliner, either for real or in the sim, into a stick shaker with the autopilot on? I can't remember doing so. I would imagine that having the a/p kick off as the stick shaker fires could lead to some interesting reactions!

As I said, I dunno what happened. I am trying to understand - 3407 hit pretty close to home with me. But I am far from convinced that the 121 way of doing stall recoveries is foolproof.

 

[Newf Dog]

Regarding taking a closer look at airline stall training:

I know that stall training did change at Comair after the Pinnacle accident for the simple reason that stall recognition and recovery techniques in the low altitude terminal environment (classic stall spin scenario) are different than stall recognition and recovery techniques in the high altitude environment.

Training and FSM were adjusted to reflect this disparity. Not saying it's relevant here necessarily. It's just that accidents usually do reveal areas where training needs to be adjusted. Unfortunately that is the "blood priority" with which we are all too familiar.

 

[livin'thesim]

I'm with q100. The problem is that smoothness is over-emphasized in many 121 programs' stall recovery training.

The emphasis on altitude control by many check airmen causes, in my opinion, too much concern about the wrong thing.

The typical 121 stall training works well for crews that find themselves a little slow, and just bumping into the shaker a bit.

It's not aggressive enough for a full-stall situation.

In reality, what passes for stall training in the transport category world would be better termed: Recovery from unintentional slow flight
training.

The nonsensical emphasis on altitude control in simulators instead of pitch control is not helping.

Pitch control is much easier to train, and it leads to more consistent results in training. Also, it gets the eyes where they need to be, which is on the aircraft's pitch attitude.

I've done my share of time as a sim instructor, and I am not at all convinced that typical 121 "stall training" should even have the word 'stall' in it.

 

[WSurf]

Thanks for reply - I actually am aware of all you are saying. 5000+ hours on Dash8 100s....

It's not bass ackwards in general, but it is bass ackwards from the way we learn stall recoveries from day one of student pilot training, which is first and foremost reduce the angle of attack by reducing pitch.

And my point was this - in trying to maintain pitch attitude against a pusher, a pilot could conceivably use enough force to over-ride the pusher, at which time 80# of backpressure would be transmitted to the elevator un-opposed, with a pretty rapid pitch up almost inevitable.

Also, have any of us driven an airliner, either for real or in the sim, into a stick shaker with the autopilot on? I can't remember doing so. I would imagine that having the a/p kick off as the stick shaker fires could lead to some interesting reactions!

As I said, I dunno what happened. I am trying to understand - 3407 hit pretty close to home with me. But I am far from convinced that the 121 way of doing stall recoveries is foolproof.

True, and I understand where your coming from. And with the Stick PUSHER coming on, I would agree with you that your only recourse at that time is to lower the pitch while adding power. I mean the plane is yelling at you "hey dummy lower the pitch and increase airspeed I am about to stop flying."
But like I said, I think maybe the crew was really worried about the ice and it became their main focus rather then the airspeed of the plane. 2 pilots and neither one watchin the planes airspeed get to 134kts with no gear selected down. I believe they were both worried about ice on the windshield and wings.



Back to the Stick Pusher: We usually don't train that point of pusher or shaker, mainly because you should never, ever, ever allow that plane to even get close to that point.

You are right in the fact that Stick Shaker and Stick Pusher recovers would be different.

 

[livin'thesim]

You're right, and you may have hit on the real tragedy here. The distraction from the ice may have been a bigger factor than the aerodynamic effect.

 

[ackattacker]

I can say that in my 121 training I never did any maneuver that resulted in a stick pusher. I have no idea what it feels like, how far the nose drops, etc. Stall training goes to the shaker and then recovery... and with the autopilot off. I'd expect this accident may (and should) result in a change in training.

 

[Flyin2low]

Also, have any of us driven an airliner, either for real or in the sim, into a stick shaker with the autopilot on? I can't remember doing so. I would imagine that having the a/p kick off as the stick shaker fires could lead to some interesting reactions!

Actually my airline does.

But I think you mean 'stick pusher'. And a fed had the IP do that to us on our type ride in the CRJ. While doing an approach briefing on downwind, stick pusher activates and A/P disconnects. The funniest thing was that after releasing the A/P disconnect, it did it again until we figured out to turn off one of the stick pusher switches.