Continental TurboProp crash inbound for Buffalo
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The NASA video does not create a simulation of the flight conditions for the accident. It explains tailplane stalls as a function of icing within a controlled environment.
It would be a truer depiction if a simulation is made (using NASA software) showing the elements of flight where atmospheric conditions are known to be variable.
Where did so much ice come from? Is the fuel temperature causing condensation on the wing surface (ethanol)? What change in temperature is too extreme to change from flight levels as indicated? Why isn't the de-ice system keeping up with conditions?
There is a point of order regarding the principles of this flight but not its elements.
Is the Dash-8 STOL wing?
NASA/TM—2003-212115
It would be a truer depiction if a simulation is made (using NASA software) showing the elements of flight where atmospheric conditions are known to be variable.
Where did so much ice come from? Is the fuel temperature causing condensation on the wing surface (ethanol)? What change in temperature is too extreme to change from flight levels as indicated? Why isn't the de-ice system keeping up with conditions?
There is a point of order regarding the principles of this flight but not its elements.
Is the Dash-8 STOL wing?
NASA/TM—2003-212115
A high-fidelity simulation model for icing effects flight
training was developed from wind tunnel data for the
DeHavilland DHC-6 Twin Otter aircraft. First, a flight
model of the un-iced airplane was developed and then
modifications were generated to model the icing
conditions. The models were validated against data
records from the NASA Twin Otter Icing Research flight
test program with only minimal refinements being
required. The goals of this program were to demonstrate
the effectiveness of such a simulator for training pilots to
recognize and recover from icing situations and to
establish a process for modeling icing effects to be used for future training devices.
training was developed from wind tunnel data for the
DeHavilland DHC-6 Twin Otter aircraft. First, a flight
model of the un-iced airplane was developed and then
modifications were generated to model the icing
conditions. The models were validated against data
records from the NASA Twin Otter Icing Research flight
test program with only minimal refinements being
required. The goals of this program were to demonstrate
the effectiveness of such a simulator for training pilots to
recognize and recover from icing situations and to
establish a process for modeling icing effects to be used for future training devices.
Last edited by E.Z. Flyer; 14th Feb 2009 at 18:24. Reason: Reference article: Simulation Model Development for Icing
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I am extremely sorry for the loss of life. But what is it about supposed professional Pilot training? Even as a lowly and humble PPL/IR, I have read, had instilled into me, and studied the effect of ice. In as much as if you are getting iced up, dont use the flaps , you recalculate the landing distance available and if its too short, divert, unless you are certain that the tailplane is not a problem. (...) No doubt I will be vilified for this comment, as usual, and told to wait for the official report, but reports of ice on approach and then a sudden fatal dive just when they went for the flaps over the OM all adds up. I am flabbergasted how this can happen, yet again and again and again, remember people died.
The lawyers have already read all the comments, so mine are not going to make an iota of difference. In fact I hope they sue the airline out of existence
The lawyers have already read all the comments, so mine are not going to make an iota of difference. In fact I hope they sue the airline out of existence
Get a Life! Do you think we're air club week-end fly-boys?
A "humble PPL/IR" would have done, what many ATPL, 15.000h, wide-body driver's are doing here: Keeping their mouth shut and learning!
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I don't think anyone (except me in post #108) has asked this, but is it possible that the ice accumulation was so severe, that it overwhelmed the deice systems on the Q400?
All aircraft (excluding jets in this discussion) certified for flight into known icing conditions have their ultimate icing limits. The details released so far by the NTSB do seem to indicate a tailplane stall. For this to have happened, there must have been a significant ice buildup on the H stab. Newer wing shapes and newer H stab shapes are generally more sensitive to ice that older thicker airfoils. Are boot deicing systems for these newer airfoils, designed to compensate for this increased sensitivity?
I think we do have to keep in mind that there are ultimate icing limits here. If I can use an analogy, most windshield wipers on autos have 2 continuous speeds, but sometimes the rain it so heavy that even the fast speed is not enough (and you have to pull over). The Q400 has 2 speeds for boot cycling, and maybe the ice accumulation was so fast, even the fast cycle speed was not enough. The Buffalo area is just east of the Great Lakes, so there could have been very high moisture content in the air (clouds) that evening.
I also read somewhere that you should manually cycle the boots just prior to a configuration change, just in case.
All aircraft (excluding jets in this discussion) certified for flight into known icing conditions have their ultimate icing limits. The details released so far by the NTSB do seem to indicate a tailplane stall. For this to have happened, there must have been a significant ice buildup on the H stab. Newer wing shapes and newer H stab shapes are generally more sensitive to ice that older thicker airfoils. Are boot deicing systems for these newer airfoils, designed to compensate for this increased sensitivity?
I think we do have to keep in mind that there are ultimate icing limits here. If I can use an analogy, most windshield wipers on autos have 2 continuous speeds, but sometimes the rain it so heavy that even the fast speed is not enough (and you have to pull over). The Q400 has 2 speeds for boot cycling, and maybe the ice accumulation was so fast, even the fast cycle speed was not enough. The Buffalo area is just east of the Great Lakes, so there could have been very high moisture content in the air (clouds) that evening.
I also read somewhere that you should manually cycle the boots just prior to a configuration change, just in case.
Last edited by Flight Safety; 14th Feb 2009 at 15:37.
The (very interesting) NASA video lists the increase of AoA on the horizontal stabiliser due to the increased wing downwash with flap deflection as an aggravating factor. While I can understand this for a low tail configuration as on the Twin Otter, would wing downwash be a factor for T-tailed aircraft such as the DHC-8?
BR,
aerolearner
BR,
aerolearner
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Not normally for Q400. in my euoprean company the SOP is to set fast on the boots when the ICE DETECT annunciation comes up on the ED. You would have selected Prop De-ICE and the Ref switch as or slightly before you encountered the cloud, unless it was dark and you didn't know you were IMC.
However, the Dash is good at letting you know it's IMC as it bounces about a bit and whistles through the wipers in cloud (I wish I knew why!).
I've had the pleasure of the ATP and it hoovered up Ice like nothing else, and being so over powered
, just stopped climbing. The Q400 really does have an excess of power, so climbing through it is a valid and good option.
In decent, it's usual in heavier icing, like I encountered least week, that the ice clings on for a while, and when the SAT shows about +1 degree, it will start shedding. The wipers and spigot clear quite quickly, if you are at 235kts too, as you have a couple of knots of heating there too.
Usually, if you are not sure, you'll brief and bug the speeds for Icing, flap 35 and +15kts on VREF. The second bug is set at VClimb, in our SOPS, so you need to decide early in the appraoch whether it's icing or not. Re scheduling speeds (not something PNF can do for you) in a late stage of approach is not a sensible idea.
Lots of us Q400 drivers are really wondering what caused this. We do not get a lot of SIM time on icing, you just put the stuff on and it works. Individual boot failures are covered, you can isolate left and right sides, or work the system manually, (not that difficult) you just rotate a switch above the skipper's head, to ensure the contamination is symetrical.
I expect the NTSB may focus on when he put the icing on, how long for, etc. When you start it in Automatic, the sequence starts at the outer wings and works inwards before going to the tail. If you switch it off, it completes a full cycle before finishing though.
It's also rare to see a Turboprop without a few patches on boots as well.
I believe Bombardier are looking into an alternative heating system using seramic conducting coatings, but don't know any more. Using bleed air would be fine at lower altitudes, where the flat rating is in place, as the engine has plenty of margin, but not really suitable at cruise levels.
I certainly await the NTSB's report, and will refrain from speculation until then.
However, the Dash is good at letting you know it's IMC as it bounces about a bit and whistles through the wipers in cloud (I wish I knew why!).
I've had the pleasure of the ATP and it hoovered up Ice like nothing else, and being so over powered
, just stopped climbing. The Q400 really does have an excess of power, so climbing through it is a valid and good option.In decent, it's usual in heavier icing, like I encountered least week, that the ice clings on for a while, and when the SAT shows about +1 degree, it will start shedding. The wipers and spigot clear quite quickly, if you are at 235kts too, as you have a couple of knots of heating there too.
Usually, if you are not sure, you'll brief and bug the speeds for Icing, flap 35 and +15kts on VREF. The second bug is set at VClimb, in our SOPS, so you need to decide early in the appraoch whether it's icing or not. Re scheduling speeds (not something PNF can do for you) in a late stage of approach is not a sensible idea.
Lots of us Q400 drivers are really wondering what caused this. We do not get a lot of SIM time on icing, you just put the stuff on and it works. Individual boot failures are covered, you can isolate left and right sides, or work the system manually, (not that difficult) you just rotate a switch above the skipper's head, to ensure the contamination is symetrical.
I expect the NTSB may focus on when he put the icing on, how long for, etc. When you start it in Automatic, the sequence starts at the outer wings and works inwards before going to the tail. If you switch it off, it completes a full cycle before finishing though.
It's also rare to see a Turboprop without a few patches on boots as well.
I believe Bombardier are looking into an alternative heating system using seramic conducting coatings, but don't know any more. Using bleed air would be fine at lower altitudes, where the flat rating is in place, as the engine has plenty of margin, but not really suitable at cruise levels.
I certainly await the NTSB's report, and will refrain from speculation until then.
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> NASA Video
E.Z Flyer, possibly you did not watch the right video or did not watch it all the way through. It starts off using a controlled environment and explanations, shows the profiles of observed ice accumulation, and how they were recreated to disrupt air flow, and how the air flow on a tail assembly breaks loose, how the reconnection point steadily moves toward the rear, and how that reconnection point eventually reconnects on a movable rather than a fixed surface, deflecting it.
It does take patience to watch the video through the educational material.
If you quit partway you will have missed the actual videos taken in actual flight by the actual test pilots, including the actual tail stall experienced while they were trying to creep up on the conditions where it was expected.
It does take patience to watch the video through the educational material.
If you quit partway you will have missed the actual videos taken in actual flight by the actual test pilots, including the actual tail stall experienced while they were trying to creep up on the conditions where it was expected.
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Continental Fight 3407 Weather 2/12/09
I just listened to the ATC recordings, via flightglobal.com.
The first readback she did was normal with all the details/clearances.
The second and last 1 was short, without details as if something already was going on up front.
Anybody heard the same?
RIP
The first readback she did was normal with all the details/clearances.
The second and last 1 was short, without details as if something already was going on up front.
Anybody heard the same?
RIP
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I find that very hard to believe. I would classify the 747 and A380 as "really, really" large planes and their wings are protected. What is Lockheeds secret with the C5 ?!
As to the A380 icing systems? I don't know what the A380 uses, not very familiar with its detailed systems. But I bet you they use wing AI even more infrequently than I do on the 400, if it even has such a system.
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The (very interesting) NASA video lists the increase of AoA on the horizontal stabiliser due to the increased wing downwash with flap deflection as an aggravating factor. While I can understand this for a low tail configuration as on the Twin Otter, would wing downwash be a factor for T-tailed aircraft such as the DHC-8?
The downwash flow field extends considerably above and below the plane of the wing. Think of the downwash as being the necessary opposite reaction by the air to the wing generating lift - the air pushes the plane "up", so the plane must push air "down". Now, if the air passing close to the wing is diverted "down", then the air below the wing has to "get out of the way" a bit and the air above the wing gets dragged downwards into the "gap". Eventually you get far enough above/below the wing flow that the downwash effect has decayed enough that it has "gone away" - but at the height of a typical "high tail", the downwash is still having an effect.
There was a noticeable change in her voice in the last transmission, sounded a bit shaky.
What you feel is subjective and of no use to the investigation unless it is qualified by expertise. All the more reason why the CVRs are generally not released to the public.
My suggestion is stick to the words or lack of and not the voice behind the words
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The NASA video does not create a simulation of the flight conditions for the accident. It explains tailplane stalls as a function of icing within a controlled environment.
It would be a truer depiction if a simulation is made (using NASA software) showing the elements of flight where atmospheric conditions are known to be variable.
It would be a truer depiction if a simulation is made (using NASA software) showing the elements of flight where atmospheric conditions are known to be variable.
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Assessing of voice stress
IOMAPASEO I agree. There is no point in anybody trying to interpret the intonation or tension in cockpit voices unless one has data on what might be happening to the aircraft at the time of the transmission. This will come in due course but we are not party to that data at this stage so comments are pure speculation and hardly worth making.
However, everything seems to point to a loss of control due most likely to an icing problem at a critical stage in the descent. Very, very sad. There but for the Grace etc. etc.
However, everything seems to point to a loss of control due most likely to an icing problem at a critical stage in the descent. Very, very sad. There but for the Grace etc. etc.
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Time on type?
I haven't seen this mentioned in this thread yet, but I've heard some news reports -- can't vouch for their accuracy -- that although the pilot was fairly experienced, his time on type for the Dash-8 was rather short. Given the NASA video's emphasis on familiarity with aircraft type to discern potential tail plane icing symptoms, and others on this thread reporting rather skimpy training for tail plane stalls, could this limited time on type be a contributing factor here?
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+1 on the credentials thing.
The uninformed in here make me think of the 'talking heads' on TV.
I can assure you all that ANYONE flying a T-tail airplane after Roselawn recieved extensive training on the onset of tailplane stalls. (I was in a DC9/MD80 at the time). Perhaps someone was sleeping thru that sim session, or had never ACTUALLY felt the onset (as you would if the autopilot was off) or they were mentally playing golf that day.
History forces those who forget to repeat itself. Those lessons are usually written in blood. If you're reading this, it's someone elses' blood there on that checklist. If you didn't read it, or skipped it, it will be written in yours someday. God help everyone in your plane.
Yes, I know that's harsh, but put yourself 15 miles further back towards EWR the other night. How harsh would you have been?
The uninformed in here make me think of the 'talking heads' on TV.
I can assure you all that ANYONE flying a T-tail airplane after Roselawn recieved extensive training on the onset of tailplane stalls. (I was in a DC9/MD80 at the time). Perhaps someone was sleeping thru that sim session, or had never ACTUALLY felt the onset (as you would if the autopilot was off) or they were mentally playing golf that day.
History forces those who forget to repeat itself. Those lessons are usually written in blood. If you're reading this, it's someone elses' blood there on that checklist. If you didn't read it, or skipped it, it will be written in yours someday. God help everyone in your plane.
Yes, I know that's harsh, but put yourself 15 miles further back towards EWR the other night. How harsh would you have been?
Last edited by singpilot; 14th Feb 2009 at 19:33.
There appears to be a post missing.
Somebody described the Q400 system, which suggested that wing and h+v stabs anti-ice were all switched on together.
Or did I dream that post?
If that is the case, then the tail icing would become a red herring. If anti-ice was on, then neither wing or tail should have had ice accretion. For tail icing to occur, a fail signal for the boots should have alerted the crew well before it became a problem? Or - it was not on, and everything iced - hard to believe.
Re: the CVR, the last transmission seems to me to be unprompted, previous comm was a readback with a humorous inflection towards the end, there was no comm from ATC requiring anything from them thereafter.
Somebody described the Q400 system, which suggested that wing and h+v stabs anti-ice were all switched on together.
Or did I dream that post?
If that is the case, then the tail icing would become a red herring. If anti-ice was on, then neither wing or tail should have had ice accretion. For tail icing to occur, a fail signal for the boots should have alerted the crew well before it became a problem? Or - it was not on, and everything iced - hard to believe.
Re: the CVR, the last transmission seems to me to be unprompted, previous comm was a readback with a humorous inflection towards the end, there was no comm from ATC requiring anything from them thereafter.
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I understand, maybe I was harsh to go off on your post. I think it was just the one that "broke the camel's back" regarding a lot of previous, ridiculous un-informed posts.
But a re-design based on speculation seems a little extreme to me. If anything, maybe it belongs on its own thread, because there is certainly no evidence yet in this one that deems a "re-design" is a solution. Maybe that might be the case as it was in the Roselawn tragedy (it certainly doesn't take an expert to find similarities in both), but I really think it is premature.
Anyone can make observations, that is all we are doing here. I just wish that wanna-bes would start their own forum and post there, or at least only read topics that they don't understand as opposed to offering their expert opinion with terminology whose meaning they don't really understand.
But a re-design based on speculation seems a little extreme to me. If anything, maybe it belongs on its own thread, because there is certainly no evidence yet in this one that deems a "re-design" is a solution. Maybe that might be the case as it was in the Roselawn tragedy (it certainly doesn't take an expert to find similarities in both), but I really think it is premature.
Anyone can make observations, that is all we are doing here. I just wish that wanna-bes would start their own forum and post there, or at least only read topics that they don't understand as opposed to offering their expert opinion with terminology whose meaning they don't really understand.
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Just watched the live NTSB press conference.
Notable points were that the stick shake and push systems were active just prior to the crash, de-icing systems appear to have been working fine on preliminary examinations, and the engines look to have been working as normal. The state of the wreckage strongly indicates that the plane crashed in the level flight position, and not a nose-dive as had been reported, and most notably was that the plane is facing north east, but was landing on a south west facing runway (23).
That's just a summary. Watch Sky News for the full press conference.
I'm just the messenger relaying exactly what he just said here - no opinion added from me.
Notable points were that the stick shake and push systems were active just prior to the crash, de-icing systems appear to have been working fine on preliminary examinations, and the engines look to have been working as normal. The state of the wreckage strongly indicates that the plane crashed in the level flight position, and not a nose-dive as had been reported, and most notably was that the plane is facing north east, but was landing on a south west facing runway (23).
That's just a summary. Watch Sky News for the full press conference.
I'm just the messenger relaying exactly what he just said here - no opinion added from me.