Colgan Q400 Down near KBUF?

scottd said:
Lance,

Not sure where you are getting that the report only lasted one minute. In the remarks it says that freezing rain BEGAN at 58 minutes after the hour and snow ENDED at 58 minutes past the hour.

Although, I do think that the FZRA report might have been incorrect. I dug up a report from another site that was a "corrected" report at 0505 UTC that did not include FZRA.

KBUF 130505Z COR 25012KT 4SM -SN BR BKN008 BKN015 OVC021 01/00 A2983 RMK AO2 CIG 005V011
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I'm pretty certain I saw a METAR from BUF that indicated a pair of began and ended times that were one minute apart e.g begin 47 end 48. I would also assume that an identical begin/end pair would indicate equal to or less than 1 minute of precip, is that correct? Seems like for an hour duration, the begin and end times would be in different METARs.

Based on my look, they descended out of 16,000 feet into IMC about 11,000 feet (and that seems to be supported by the CVR and cloud top temperatures on the IR satellite). They would remain in conditions that still had a considerable probability of supercooled liquid water through the point of descending on the ILS approach. If so, they could have accreted a good bit of ice in that time period, especially if there were spotty areas of freezing rain or freezing drizzle aloft. They were on the edge of some heavier precipitation that had 25 - 30 dBZ refectivity. Moreover the BUF 0000 UTC RAOB clearly exhibits a temperature inversion between 5,000 and 6,000 feet that can increase the drop sizes as are discussed in my training programs.
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That mostly makes sense to me but if the tops were around 11000 MSL (that was my take as well from both the Skew-T and the ATC transcript) how could there be any freezing rain at or slightly below 11000? Seems like you'd need a vertical extent well above that to generate rain at that altitude. And it's my contention (albeit not necessarily a given) that once they started down from within the cloud layer tops they would have been in a pretty much continuous descent which should mean that they'd be through any layers of SLD rather quickly. IIRC both the Roselawn and the DTW incidents involved flying at a constant altitude for an extended period in the SLD, and in the case of Roselawn they were actually holding and thus making repeated passes through the worst of it. A common method of dealing with icing is penetrating with a rapid descent, I hope this is a valid strategy.

And that's the issue, runback or drops that penetrate the boundary layer behind the protected surfaces which is common in SLD scenarios. You can't shed this ice and it then becomes an efficient ice collector.
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Understood. If the flight experienced that they were indeed in serious trouble the moment ice started to accrue behind the boots. And I would think that since the crew had noticed ice on the wings, they would have also noticed if it was building behind the boots and would have been aware of the significance of that. I sure know that would get my full attention as soon as my heart began beating again if I ever saw that happening to my wings.

BTW, here is a very good report just to the west of Buffalo of light to moderate rime from 3,000 to 6,000 feet.

YZ UA /OV CYHM 090035 /TM 0334 /FLDURD /TP C208 /IC LGT-MDT RIME 030-060 /RM TEMP A030 -4, A060 -10
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I have no doubt that icing conditions existed, I'm still surprised that it was severe enough to down that plane if it's deice systems were operating as designed. Hopefully a more detailed transcript of the CVR will shed some light on whether or not ice was building behind the boots due to runback.

One other part of the reports so far that I think is a bit puzzling is that the FDR logged significant excursions in pitch and roll which doesn't seem consistent with a tailplane stall, but it would make sense if the upper surfaces of the wings were severely contaminated as well as the tail.
 
SkyHog said:
I assume that won't include the deleted message though, will it?
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smigaldi said:
I hope not.
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The Google cache can, indeed, have deleted messages. I have no idea if the google bot caches everything it sees but I have no reason to think it wouldn't.

More than one web site has gotten busted on changes made.
 
This article just appeared.
Continental Connection Flight 3407 didn't nose-dive into the house, as initially reported by some witnesses, said Steve Chealander, a National Transportation Safety Board member.
The Newark, N.J.,-to-Buffalo flight was cleared to land on a runway pointing to the southwest, but it crashed with its nose pointed northeast, Chealander said.
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That seems to disagree with the initial report that the plane entered a steep nose/wing low attitude when the flaps were extended. Also seems to me that it places some doubt on the tail stall theory (which is where I had my money, so to speak). Any idea where one can find these NTSB reports and updates that these unending news releases keep talking about?
 
Teller1900 said:
This article just appeared.


That seems to disagree with the initial report that the plane entered a steep nose/wing low attitude when the flaps were extended. Also seems to me that it places some doubt on the tail stall theory (which is where I had my money, so to speak). Any idea where one can find these NTSB reports and updates that these unending news releases keep talking about?
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How do you explain the compact debris field? A severe nose down attitude is an explanation.
 
Depending on the aircraft, a non-flat spin can have pitch changes from very nose down to almost flat during rotation. It could have easily been a spin and landed just as indicated. An initial nose drop would lead to the witness reports of a nose dive. The apparent flight recorder indications of roll excursions also sounds to me like incipient spin behavior.
 
apparently so...for the most recent one, which I suppose is the one you want. Let me look further; or await a better searcher...
 
I was chatting with a friend that flies 757s who commented he just didn't know how putting flaps down would affect the T-tail on this plane. Might not disrupt the airflow as much as a normal horizontal stab that is directly behind the airstream from the flaps. Shed a little doubt on the tail stall speculation.

Best,

Dave
 
Dave Siciliano said:
I was chatting with a friend that flies 757s who commented he just didn't know how putting flaps down would affect the T-tail on this plane. Might not disrupt the airflow as much as a normal horizontal stab that is directly behind the airstream from the flaps. Shed a little doubt on the tail stall speculation.
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Maybe not as much as if it were a low tail, but it certainly would change the airflow over the T-tail to some extent. The T-tail is not that far above the flaps of this high-wing airplane, and the flaps will create downwash a considerable distance above as well as below the level of the wing. I think the major advantage of T-tail in aircraft such as this is to reduce cabin vibration by getting the tail out of the propwash.
 
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Just saw a news blurb that the stick shaker was activated and that the aircraft was still on autopilot...despite the Colgan operations manual requiring "hands on" operations in iceing conditions of the type it appears they encountered. Anyone else have any information on this?
 
Pilawt said:
Maybe not as much as if it were a low tail, but it certainly would change the airflow over the T-tail to some extent. The T-tail is not that far above the flaps of this high-wing airplane, and the flaps will create downwash a considerable distance above as well as below the level of the wing. I think the major advantage of T-tail in aircraft such as this is to reduce cabin vibration by getting the tail out of the propwash.
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I think the lowering of flaps is more of a pitching moment issue (i.e. it requires more downforce from the tail) than a disturbed airflow issue.

That's why you don't use flaps if you suspect icing. You might have ice on the tail and stall the tail before the wing.
 
kyleb said:
I think the lowering of flaps is more of a pitching moment issue (i.e. it requires more downforce from the tail) than a disturbed airflow issue.

That's why you don't use flaps if you suspect icing. You might have ice on the tail and stall the tail before the wing.
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Extending flaps results in an increase in the (negative) angle of attack on the tail, and therein lies the problem. The increased angle of attack comes from the downward deflection of air behind the wing, both above and below the level of the wing, when flaps are extended. That deflected air strikes the tail from above, changing the angle of attack of the fixed horizontal stabilizer. That increased (negative) angle of attack results in increased downward "lift" which offsets, at least in part, the increased downward pitching moment from the center of lift moving aft with flap extension. Some upward elevator deflection may also be needed to maintain the desired attitude. The NASA video demonstrates this, at about 6:00 to 8:00 into the clip.
 
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Pilawt said:
Extending flaps results in an increase in the (negative) angle of attack on the tail, and therein lies the problem. The increased angle of attack comes from the downward deflection of air behind the wing, both above and below the level of the wing, when flaps are extended. That deflected air strikes the tail from above, changing the angle of attack of the fixed horizontal stabilizer. That increased (negative) angle of attack results in increased downward "lift" which offsets, at least in part, the increased downward pitching moment from the center of lift moving aft with flap extension. Some upward elevator deflection may also be needed to maintain the desired attitude. The NASA video demonstrates this, at about 6:00 to 8:00 into the clip.
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Extending flaps also generally requires a more nose down pitch attitude for the same speed and this contributes to the increased AoA on the tail at least as much as the increased downward deflection of air over the main wing, especially on a T-tail.
 
rollcloud2001 said:
Just saw a news blurb that the stick shaker was activated and that the aircraft was still on autopilot...despite the Colgan operations manual requiring "hands on" operations in iceing conditions of the type it appears they encountered. Anyone else have any information on this?
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As was covered in the 4:00 NTSB brief today:

The only autopilot limitation that exists regarding icing is a Bombardier limitation that states: The autopilot is not to be used in severe icing. According to the NTSB, it does not appear as if there were any available signs that they were in severe icing, so they were well within the limitations of the auto pilot. The NTSB says the news got this wrong - the autopilot is allowed in icing conditions.
 
I don't know about this plane or what the company's procedures are, but many plane POHs and experienced folks I know suggest flying with the AP off in icing conditions because use of the AP can mask handling problems from ice accumulation. It may not be prohibited, but if the AP reaches control limits and kicks off with significant ice accumulation at low altitude, it can compound control problems. Or, control issues a pilot may sense flying manually, might not be picked up if the AP is engaged.

Best,

Dave
 
Cross-post from the Tail plane Icing Video Thread:

I'm wondering what kinds of simulator training takes place the various professional pilots here have had with regard to aircraft icing. Do they include tail-plane stall scenarios?

We have the ability to simulate icing conditions on our glass Frasca simulator but I've never dealt with it and I doubt anyone else here (at my school) has. This film has encouraged me to dig into that area and learn more about how I can apply it to training, especially with instrument students.
 
One of the fellas that organized the Advanced Baron seminar each year commented that the sim can't really replicate a tail plane stall; all it can do is load the tail up. Maybe something else can be done, but in our sims, it wouldn't really replicate the event. It also seems to me that a tail plane stall could have different characteristics each time it occurred. That is, different kinds of ice, accumulation in different places, etc. Not saying there wouldn't be a benefit to sim training. One would just have to pick a scenario.

Current training seems to be more focused on systems use and procedures. Turning boots on, hot plate, and other systems. Manual cycling of the boots in my plane. In the P-Baron, there is a minimum IAS to keep the wings clean behind the boots.

I belive I may have had a tail plane stall on my other plane (A-36) once climbing through icing conditions. I was at 9,000 feet and climbing when my rate of climb materially decreased. When I lowered the nose, I actually began to climb again. I broke out of clouds shortly aftward. The controls were very heavy. I'm not sure, but things seemed to work better with opposite control in the climb until the ice sublinated off the horizontal stab. There wasn't a lot on there that I could see visually, but I sure could feel it on the controls.

Best,

Dave
 
If you had a tailplane stall, lowering the nose (i.e. moving the wheel forward) would have made things worse. Also AFaIK, a tail stall will not decrease your ROC unless your CG is so far aft that the tail is actually providing upward lift. Based on your description, I'd guess that you actually experienced either the onset of a wing stall, or more likely just a shift in the optimal AoA for climb due to airflow disrupted by ice.

-lance

Dave Siciliano said:
I belive I may have had a tail plane stall on my other plane (A-36) once climbing through icing conditions. I was at 9,000 feet and climbing when my rate of climb materially decreased. When I lowered the nose, I actually began to climb again. I broke out of clouds shortly aftward. The controls were very heavy. I'm not sure, but things seemed to work better with opposite control in the climb until the ice sublinated off the horizontal stab. There wasn't a lot on there that I could see visually, but I sure could feel it on the controls.

Best,

Dave
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lancefisher said:
If you had a tailplane stall, lowering the nose (i.e. moving the wheel forward) would have made things worse. Also AFaIK, a tail stall will not decrease your ROC unless your CG is so far aft that the tail is actually providing upward lift. Based on your description, I'd guess that you actually experienced either the onset of a wing stall, or more likely just a shift in the optimal AoA for climb due to airflow disrupted by ice.

-lance
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That's what I recall most from the video. It's opposite of our usual instinct in recovering from a stall. From what they discussed in the film in getting the pilot to respond correctly, it sounded as bad or worse than a primary student refusing to let the yoke go neutral during a wing stall.

We know how the horizontal stabilizer and elevator works from ground instruction. But, to remember that at the time of a tailplane stall occurrence and react correctly... it would take some substantial conditioning for some to react correctly on top of recognition of a tailplane stall.
 
lancefisher said:
If you had a tailplane stall, lowering the nose (i.e. moving the wheel forward) would have made things worse. Also AFaIK, a tail stall will not decrease your ROC unless your CG is so far aft that the tail is actually providing upward lift. Based on your description, I'd guess that you actually experienced either the onset of a wing stall, or more likely just a shift in the optimal AoA for climb due to airflow disrupted by ice.

-lance
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Well, maybe I'm recalling incorrectly. Normally in a climb with 120 IAS, if I wanted the ROC decreased, I would raise the nose to increase ROC (and lower IAS). I tried that and ROC decreased. When I lowered the nose, the nose pitched up and ROC increased. Up/down control was just backward. Don't know what happened, but opposite control did the trick. I didn't see any ice on the wing. Could have been underneath. I could see ice on the horizontal stab.

Best,

Dave
 
Dave Siciliano said:
Well, maybe I'm recalling incorrectly. Normally in a climb with 120 IAS, if I wanted the ROC decreased, I would raise the nose to increase ROC (and lower IAS). I tried that and ROC decreased. When I lowered the nose, the nose pitched up and ROC increased. Up/down control was just backward. Don't know what happened, but opposite control did the trick. I didn't see any ice on the wing. Could have been underneath. I could see ice on the horizontal stab.
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Dave, maybe the combined effects of the ice on all areas of the airframe could have put you slightly behind the power curve at your climb speed? :dunno:
 
Matt,

If you don't feel comfortable answering these questions then I completely understand. The media hasn't mentioned anything about fatigue or duty time for the crew, do you by chance know how many hours they had been on duty/flown? Do you know how many legs they had flown, how many legs a typical day at Colgan entails on the Q? I fear that the media is already starting to point the finger at the crew and it seems premature to me to say the least. Of course, you are going to have Colgan/Pinnacle, Bombardier, and the FAA defending the airplane.

Thanks,
 
Auburn_CFI said:
Matt,

If you don't feel comfortable answering these questions then I completely understand. The media hasn't mentioned anything about fatigue or duty time for the crew, do you by chance know how many hours they had been on duty/flown? Do you know how many legs they had flown, how many legs a typical day at Colgan entails on the Q? I fear that the media is already starting to point the finger at the crew and it seems premature to me to say the least. Of course, you are going to have Colgan/Pinnacle, Bombardier, and the FAA defending the airplane.

Thanks,
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I think the smart thing to do at this point for Matt is to politely decline replying to such request. I would suggest if you want to talk on a professional level do it through a PM.
 
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Auburn_CFI said:
Matt,

If you don't feel comfortable answering these questions then I completely understand. The media hasn't mentioned anything about fatigue or duty time for the crew, do you by chance know how many hours they had been on duty/flown? Do you know how many legs they had flown, how many legs a typical day at Colgan entails on the Q? I fear that the media is already starting to point the finger at the crew and it seems premature to me to say the least. Of course, you are going to have Colgan/Pinnacle, Bombardier, and the FAA defending the airplane.

Thanks,
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I wouldn't answer any of those questions if I were him. While it is nice having people who have connections to various parts of the aviation industry giving us additional insight into what goes on, those of us involved with it also shouldn't, and in some cases can't, answer specific questions as to operations of the company if we value our jobs. That is also not our place, as there are other departments within the companies to answer those questions. Also, keep in mind the answers we have may not always be correct. Just working at the company doesn't provide us with all the answers. :)
 
flyingcheesehead said:
Dave, maybe the combined effects of the ice on all areas of the airframe could have put you slightly behind the power curve at your climb speed? :dunno:
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That's along the lines of what I was thinking. You don't have to be behind the power curve (minimum power required speed) just below the actual Vy. At that point if you pitch up your ROC will decrease. I'm assuming that the ice (wherever it was at) raised the actual Vy and at 120 KIAS Dave was already right about at where Vy would be with no ice.
 
Ted DuPuis said:
I wouldn't answer any of those questions if I were him.
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I wouldn't either, not even in private.

Ted DuPuis said:
While it is nice having people who have connections to various parts of the aviation industry giving us additional insight into what goes on, those of us involved with it also shouldn't, and in some cases can't, answer specific questions as to operations of the company if we value our jobs. That is also not our place, as there are other departments within the companies to answer those questions.
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Exactly, and that is even more true when there is an active accident investigation going on. Actually I'm surprised that more companies don't give their employees guidance about this. It should be part of an emergency plan.
 
I don't understand why there's such secrecy in this stuff. Its not like releasing information about the airplane/airframe/crew can interfere with the NTSB's research, as they should be able to get the information they're seeking anyways.

I honestly can't think of a single thing someone can say that will cause delay in the investigation.
 
SkyHog said:
I don't understand why there's such secrecy in this stuff. Its not like releasing information about the airplane/airframe/crew can interfere with the NTSB's research, as they should be able to get the information they're seeking anyways.

I honestly can't think of a single thing someone can say that will cause delay in the investigation.
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It has nothing to do with delaying the investigation or hindering the research. If you are the owner of a company you want to have some control the information being released and it's usually done through a spokesman.
 
SkyHog said:
I don't understand why there's such secrecy in this stuff. Its not like releasing information about the airplane/airframe/crew can interfere with the NTSB's research, as they should be able to get the information they're seeking anyways.

I honestly can't think of a single thing someone can say that will cause delay in the investigation.
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I think the problem comes from the slightest thing said being taken by a member of our wonderful media and presented further to the public... after it has been read or listened to by the ignorant, twisted by the supposed experts and then misstating it as fact to the uninformed.

If word of identity gets back to the airline about the person making original statement, it could hurt them in some fashion.

A fellow instructor said he heard one little quip that the plane had made a 180 degree turn to remove the ice. That's why it was pointed the other way on the ground. In the same story he heard, "In the event of a stall, the plane is designed to automatically increase airspeed by twenty knots." There's enough ignorance being spread around. It doesn't need any help.

Matt knows the plane very well, I'm sure. Yet, like the rest of us, I imagine he is still speculating the events leading up to the final outcome. I'm sure it's more important to him since his own safety may rely on that knowledge. At the same time, I'm sure he has a heavy heart carrying the loss of fellow pilots he knew with them doing the same thing he loves to do. In time, he may share. Until then, let the man have his peace. He deserves it.
 
SkyHog said:
I don't understand why there's such secrecy in this stuff. Its not like releasing information about the airplane/airframe/crew can interfere with the NTSB's research, as they should be able to get the information they're seeking anyways.
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Liability, for one. Whether or not you're in public relations, if you work for a company you can be held as representing that company when you speak, even if you state that it's clearly your opinion and doesn't represent the company's opinion. Even if it doesn't result in legal action against the compay, it can result in action against you, and it just doesn't look good.

What it comes down to is there are a lot of questions that I simply won't address or, if I do address them, will do so by pointing to company publications, not with conjecture. That includes to my closest friends. The last thing I need is one of them saying "Well, according to my friend at..."

I honestly can't think of a single thing someone can say that will cause delay in the investigation.
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It's not just delays, it's false information going around, which is bad for everything. Far too many people have already been spreading that with their theories, and certain people "know" what happened already (funny enough, most of the ones I talk to have never flown a plane). The responsible thing to do on our parts (and for aviation as a whole) is to let the investigators do their job, find out what happened, and tell us. I'd believe that the NTSB investigators are far, far more qualified to figure out what happened than we are, especially since they have much more information than we do. Doesn't mean that some of the guesses were wrong (one of them is probably right), but we're guessing.

Also, just because you can't think of anything that could be said that would delay the investigation doesn't mean there isn't anything (I can't think of anything either, though).
 
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