Russian B737 Crash at Kazan.
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The security video does look disturbingly reminiscent of the NTSB recreations of the US 737 rudder hard-over incidents though...
Board Meeting Animations - Uncontrolled Descent and Collision with Terrain USAir Flight 427 Boeing 737-300, N513AU, Near Aliquippa, Pennsylvania, September 8, 1994
Board Meeting Animations - Uncontrolled Descent and Collision with Terrain USAir Flight 427 Boeing 737-300, N513AU, Near Aliquippa, Pennsylvania, September 8, 1994
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DOVES:
Regarding your point 2, no the flash at 4s is not an explosion. As someone pointed out already it is just a strobe light on the plane. You can see a previous flash at 2s into the video, reflected from the ground.
I'm sure someone might know the 737 strobe interval, but 2s is about right compared to this video:
Any explosion is not going to be so brief (single frame) even at the low frame rate of the video.
Regarding your point 2, no the flash at 4s is not an explosion. As someone pointed out already it is just a strobe light on the plane. You can see a previous flash at 2s into the video, reflected from the ground.
I'm sure someone might know the 737 strobe interval, but 2s is about right compared to this video:
Any explosion is not going to be so brief (single frame) even at the low frame rate of the video.
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VFD:
even if you were to roll inverted and suddenly pull back on the yoke do a splits-s it would be hard for 73 to get into that attitude below 1000' unless the aircraft were to enter the initial stages of a spin ( incipient spin ) or some sort of catastrophic structural failure..
The assessment from the video seems spot on.
From the camera angle the aircraft comes down near vertical straight into the ground.
It would be hard to transition from a normal approach and get to a vertical attitude in a 737 in 700 ft at approach speed without rolling into a vertical attitude.
Even with a flap asymmetry that stops transition of flaps should not leave you in a situation that lets the aircraft be uncontrollable.
Giving the benefit of the doubt to the pilots, it sure looks like a control panel issue.
From the camera angle the aircraft comes down near vertical straight into the ground.
It would be hard to transition from a normal approach and get to a vertical attitude in a 737 in 700 ft at approach speed without rolling into a vertical attitude.
Even with a flap asymmetry that stops transition of flaps should not leave you in a situation that lets the aircraft be uncontrollable.
Giving the benefit of the doubt to the pilots, it sure looks like a control panel issue.
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If the video being shown is the correct video showing the actual accident, no reason to believe it is not, it reminds me of the old rudder hard over accidents involving 737s years ago.
The two I remember the best was the one at Colorado Springs and the one at Pittsburgh (I think) as I flew over both accident sites.
The rudder hard over caused accidents were near vertical impacts.
I thought that Boeing had fixed that problem. Something to think about anyway and I'm not saying that is the cause of this accident.
The two I remember the best was the one at Colorado Springs and the one at Pittsburgh (I think) as I flew over both accident sites.
The rudder hard over caused accidents were near vertical impacts.
I thought that Boeing had fixed that problem. Something to think about anyway and I'm not saying that is the cause of this accident.
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The rudder hard over caused accidents were near vertical impacts.
So did SE go rounds with no rudder: lets' wait and see then add wise contributions instead of speculations. The FDR should be quite modern; CVR also.
So did SE go rounds with no rudder: lets' wait and see then add wise contributions instead of speculations. The FDR should be quite modern; CVR also.
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BBC talking about vertical landing and journalist talking about vibrations when landing at Moscow on previous leg. Crap concrete runways do tend to give some vibration on landing. Vertical landing suggests it was a bloody helicopter not fixed wing. I do wish the instant expert reggie spotters would STFU and let the pro's get on with the real job of finding out what really happened. Uninformed speculation does not help. Just think that there are thousands of other 737 crews and passengers out there flying the same aircraft
Rant over.
Rant over.
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OK, I'm not a flying expert, however I know enough about aerodynamics and the outline capabilities of a B737-sized aircraft.
Given that this aircraft was initiating a GA went everything went really pear-shaped (following the unstable approach that is), then how the dickens does it end with such a high (apparently from the brief video) almost 90deg nose dive into the ground?? I mean, I wouldn't expect that it could be achieved by anything other than an astonishingly savage pull up, to near vertical climb to stall, wing over and dive....especially to remain anywhere near the vicinity of the airport security cameras?
edit: .....or stall, tumble and dive?
Given that this aircraft was initiating a GA went everything went really pear-shaped (following the unstable approach that is), then how the dickens does it end with such a high (apparently from the brief video) almost 90deg nose dive into the ground?? I mean, I wouldn't expect that it could be achieved by anything other than an astonishingly savage pull up, to near vertical climb to stall, wing over and dive....especially to remain anywhere near the vicinity of the airport security cameras?
edit: .....or stall, tumble and dive?
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lets' wait and see then add wise contributions instead of speculations
Something to think about anyway and I'm not saying that is the cause of this accident.
If I was assigned to this accident, the rudder issue would be one of the first things looked at, if for no other reason than to dismiss it as a cause as soon as possible.
I'm sure we will hear the probable cause sooner or later, hopefully.
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and wings in a steep angle of bank...
Me too, bank would also result in some kind of rolling during the dive.
To me it looks like the stabilizer suddenly let go his downward force, due to whatever reason (separation? tail stall?).
I find it hard to come up with another scenario which would result in such a sudden dive.
To me it looks like the stabilizer suddenly let go his downward force, due to whatever reason (separation? tail stall?).
I find it hard to come up with another scenario which would result in such a sudden dive.
I mean, I wouldn't expect that it could be achieved by anything other than an astonishingly savage pull up, to near vertical climb to stall, wing over and dive....
Extended lift devices (slats, flaps) can exacerbate the pitch-up tendency.
especially to remain anywhere near the vicinity of the airport security cameras?
I'm not saying that that is what happened in Kazan - I'm just pointing out that it is well within the realms of possibility.
One other factor I haven't seen noted yet is that Kazan is undergoing major reconstruction, with one large runway partially built, and the other perhaps a former taxiway being used as a runway (cf Google maps).
No reason this would lead to a crash directly - but the airport layout (combined with weather/visibility problems) could have contributed to confusion and the need for a go-around or multiple go-arounds (whichever turns out to be the fact.)
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I came not only to respect the competence of the crews....Given the utmost professionalism of MAK
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It actually reminds me of the 2 A300 crashes (Taipei and Nagoya maybe) that resulted from the crew fighting the autopilot after engaging (at least on one occasion inadvertently) GA mode on short final.
They kept pushing on the column as the AP wound in nose-up trim. When the AP finally disconnected, the trim setting could not be overcome and the aircraft went near-vertical before crashing with little forward speed on/near the runway.
I think the airline involved was China Airlines.
Perhaps a similar scenario happened on this occasion. I feel the flap thing is a red herring. I also don't think the rudder hardover theory carries much weight - Boeing's interim fix was to mandate a reduction in speed; and as this crash happened at or near final approach speed it didn't have the basic elements that the hardover accidents did.
They kept pushing on the column as the AP wound in nose-up trim. When the AP finally disconnected, the trim setting could not be overcome and the aircraft went near-vertical before crashing with little forward speed on/near the runway.
I think the airline involved was China Airlines.
Perhaps a similar scenario happened on this occasion. I feel the flap thing is a red herring. I also don't think the rudder hardover theory carries much weight - Boeing's interim fix was to mandate a reduction in speed; and as this crash happened at or near final approach speed it didn't have the basic elements that the hardover accidents did.
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Speed on impact
It seems to be hitting the ground at 0.08 in the RT video, first appearing about 5 aircraft lengths back at 0.04, assuming that the fainter trailing light is the lit fin, and the ground position comes from the location of the flash on impact. That's only covering about 150m in 4s, so it's not hitting very fast: about 80 knots.
[Added note 18:00UT on 19th: there are subsequent suggestions that the RT video is slowed to 1/4 speed. This seems a bit odd given the pair of strobe flashes seen in the 4s to impact, but strobes can be aliased to the video rate. A quarter speed video would mean a much faster ~320kt almost-vertical impact, that tallies with the reported impact speed from the MAK in post 124.]
Pointing nose down from stationary, a free falling slippery shape will hit the ground from 150m up in just over 5 seconds, although you would see it accelerate.
I would bet that the video is foreshortened, and there's a significant unseen line-of-sight component to the speed in the video.
Caveat: for the Red Wings Tu 204 crash my video time/speed counting was worse than useless.
[Added note 18:00UT on 19th: there are subsequent suggestions that the RT video is slowed to 1/4 speed. This seems a bit odd given the pair of strobe flashes seen in the 4s to impact, but strobes can be aliased to the video rate. A quarter speed video would mean a much faster ~320kt almost-vertical impact, that tallies with the reported impact speed from the MAK in post 124.]
Pointing nose down from stationary, a free falling slippery shape will hit the ground from 150m up in just over 5 seconds, although you would see it accelerate.
I would bet that the video is foreshortened, and there's a significant unseen line-of-sight component to the speed in the video.
Caveat: for the Red Wings Tu 204 crash my video time/speed counting was worse than useless.
Last edited by awblain; 19th Nov 2013 at 16:59.
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about 80 knots.