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B-738 Crash in Russia Rostov-on-Don

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B-738 Crash in Russia Rostov-on-Don

Old 21st Apr 2016, 08:11
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Originally Posted by maDJam
At a height of 900 m there was a simultaneous control column nose down input and stabilizer nose down deflection from -2,5 deg (6,5 units) to +2,5 deg (1,5 units) (the FDR recorded a nose down stabilizer input from the stabilizer trim switch of the control wheel lasting 12 seconds, while the CVR record contains a specific noise of rotation of the trim wheels located on both sides of the central pedestal), as a result the aircraft, having climbed to about 1000 m, turned into descent with negative vertical acceleration of -1g.
I still think the answer lies in that quote.

If they pushed -1g to gain the level-off altitude, and neither were familiar or comfortable with the sensations of negative g, they may well have done something unpredictable. As I said before, I have seen students either freeze and keep pushing, or think they are stalling and keep pushing. And since aeros are not a part of ATPL training, this crew may not have been familiar with negative g at all.

As I have said many times on these forums, at some point in the training, perhaps at upgrade to sfo, all pilots should do a two-week gliding course. Gliding is unique, in that it is all seat of the pants hand flying, in the most challenging conditions. In a strong bouncy thermal you might incipient stall the glider ten times while banking at 45 degrees - it is normal, and the reaction becomes normal. Positive and negative g are a central part of bouncy thermal flying. And of course all the training aircraft are certified for full aerobatics. If you are a (young) commercial pilot who has never flown a glider, I can assure you that you will come out of the course having learned many things about aircraft about aviation, and more importantly, about yourself.

ST.

(note typo error correction - changed 'pulled' to 'pushed')

Last edited by silvertate; 21st Apr 2016 at 10:00.
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Old 21st Apr 2016, 09:12
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As I have said many times on these forums, at some point in the training, perhaps at upgrade to sfo, all pilots should do a two-week gliding course. Gliding is unique, in that it is all seat of the pants hand flying, in the most challenging conditions. In a strong bouncy thermal you might incipient stall the glider ten times while banking at 45 degrees - it is normal, and the reaction becomes normal. Positive and negative g are a central part of bouncy thermal flying. And of course all the training aircraft are certified for full aerobatics. If you are a (young) commercial pilot who has never flown a glider, I can assure you that you will come out of the course having learned many things about aircraft about aviation, and more importantly, about yourself.
I fully concur!

I believe the U.S.A.F Academy cadets start out in sailplanes.

It certainly gave the GAF pilots an advantage in the early stages of WWII.
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Old 21st Apr 2016, 09:25
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At a height of 900 m there was a simultaneous control column nose down input and stabilizer nose down deflection from -2,5 deg (6,5 units) to +2,5 deg (1,5 units) (the FDR recorded a nose down stabilizer input from the stabilizer trim switch of the control wheel lasting 12 seconds, while the CVR record contains a specific noise of rotation of the trim wheels located on both sides of the central pedestal), as a result the aircraft, having climbed to about 1000 m, turned into descent with negative vertical acceleration of -1g.

I still think the answer lies in that quote.
If they pulled -1g to gain the level-off altitude,


I know what you mean, but 'pushed' might be more appropriate. But, moving on: I've read that the CVR recorded the captain's concern as to whether 8000 was set in MCP and the F/O's reply that "yes, here it is." If that was indeed the case why was there a control input at 900m to level off? The FD & HUD would still have been in TOGA climb to 8000. And for anyone to hold the pitch trim for 12 secs is unthinkable unless they were in a frozen state of panic. Both these guys had 1000's of hours and therefore I hope were competent & experienced.
I have been in a rapid climb, nose high, high speed ALT ACQ situation (B757) and reducing power was the game saver as the attitude was rapidly reduced, not trim.
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Old 21st Apr 2016, 09:29
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Originally Posted by silvertate
I still think the answer lies in that quote.

If they pulled -1g to gain the level-off altitude, and neither were familiar or comfortable with the sensations of negative g, they may well have done something unpredictable. As I said before, I have seen students either freeze and keep pushing, or think they are stalling and keep pushing. And since aeros are not a part of ATPL training, this crew may not have been familiar with negative g at all.

ST
100% True

A negative G sensation can have this effect on pilots unfamiliar with aerobatics.
There have been few strange glider accidents where students nose dived theire plane after a rope failure during a winch launch. They are trained to push hard after a rope failure to regain airspeed to a nose down attitude.
But in some rare cases the students kept pushing into nearly vertical nose dives.

The negativ g sensation triggert a "Warning, something is wrong" and the reaction "Pushing is allways good" even increased the effect and the students pushed the stick forward even more.
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Old 21st Apr 2016, 10:34
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Originally Posted by wanabee777
I fully concur!
I believe the U.S.A.F Academy cadets start out in sailplanes.
It certainly gave the GAF pilots an advantage in the early stages of WWII.
Let us be clear about what has happened in much of avaition over the last four decades.

Airlines used to select, pay for, and train pilots. Now it is often whoever comes with the money, and after 200 odd hours (and perhaps only flying in nice sunny Spanish or Arizona conditions), you are in. And then the training is all on the sim, and the sim cannot simulate many things, including fear,* sweaty palms, and negative g.

And the airlines will not pay for anything else. I pleaded with one to pay for extra circuits and bumps on a tailwheel for some underperforming fos (because sims do not simulate landings very well), but they refused. It was too expensive, even if writing-off a set of tyres would be far more expensive. Likewise, a two week gliding course would be about £1,500, full board, plus about £2000 of lost productivity - for the whole career of the pilot. Too much to ask? Yup, too much by far. Ticket prices must be less than £20, so the pilots have never done any real solo flying, by the seat of their pants, with little instrumentation, in real weather conditions - ever.

Good commercial strategy? Of course not, but it keeps the shareholders happy.

ST

* Fear - being well outside your comfort zone.
Try thermalling with 40 other gliders, if you are not fully comfortable with seat of the pants flying and using no instruments.

http://https://www.youtube.com/watch?v=dRFuWRpBa84 https://www.youtube.com/watch?v=dRFuWRpBa84 https://www.youtube.com/watch?v=dRFuWRpBa84

Last edited by silvertate; 22nd Apr 2016 at 08:32.
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Old 21st Apr 2016, 10:34
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The indicated N1s suggest thrust was advanced to the full forward stops.

Having done a previous Windshear go-around, and I suspect with the Windshear escape manoeuvre in his mind the captain (or FO - we don't know if he advanced the thrust levers further as part of "set go around thrust") made an error typical of those made by a fatigued pilot in applying parts of the wrong procedure.

Hand flying the aircraft in those conditions is pretty hard work, the more so if the aircraft is light, and the supposed "coaching" might just be the FO helping the captain out by calling wind changes from the ND or previously briefed configuration points.

Once the aircraft started rocketing away, they were reacting, and probably not in a mental condition to catch up. The duration of that trim input is astonishing - I wonder if in turbulence and with flap load relief activating, he started trimming and froze his thumb on the switch while focusing on handling the aircraft.

What we really need though are the CVR transcript and the FDR data plots.
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Old 21st Apr 2016, 10:48
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Just out of curiosity what are the crew meals (if any) like on airdubai?

i.e. by the the time they were making that 2nd approach they'd have been on duty some 8 hours, a full day's work for many people, they'd just been flying around in circles for the previous 2 hours doing, pretty much, diddly squat, plenty of time for a nice succulent meat dish meal with all the trimmings to prepare them for the remainder of their night's work, or were they pretty much starved?
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Old 21st Apr 2016, 11:06
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Let me humbly consider the following.

Correct me if I'm wrong: Load factors limits +2,5/-1 Flaps ext. +2,0/0

And we all know what to avoid to respect them.

However: do you have the slightest idea of what can happen in a passenger cabin of an aircraft submitted to negative "g"?
What goes on in a galley?
And in a toilet?
And happens to unfastened passengers and Fight Attendants?
And to pallets/bags in the hold?
I don't!

Do you remember what you should check before you start aerobatic maneuvers?

Among others (area, altitude) AIFRAME!

So I fully agree with post 1330, that of Phileas Fogg
a. After 30 minutes, 60 minutes, 90 minutes etc. in the hold "who is calling the shots?". Was a significant weather improvement forecast, or:

b. Why didn't they PDQ divert to, perhaps, Krasnodar, to sit it out there (it is acknowledged that an additional sector reduces allowable FDP by 45 minutes), or:

c. Simply divert to, perhaps, Krasnodar, dump the pax there for road transportation to Rostov, put some fuel on and return PDQ to DXB empty?
One thing I'm sure of: THIS IS MY ONLY LIFE AND I'M NOT INVULNERABLE NOR IMMORTAL

- Truly superior pilots are those who use their superior judgment to avoid those situations where they might have to use their superior skills.

One more thing.
I remember that in the last flights I made on 73 the co-pilots were taking a nasty habit of trimming pitching up during the flare (ie piloting with trim). Now?
Safe Flights
Romano
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Old 21st Apr 2016, 11:07
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Having done a previous Windshear go-around, and I suspect with the Windshear escape manoeuvre in his mind the captain (or FO - we don't know if he advanced the thrust levers further as part of "set go around thrust") made an error typical of those made by a fatigued pilot in applying parts of the wrong procedure.
Very possible. I think the data plots would help because we don't know the max pitch attitude achieved. If it is very high then the stab trim input may have been intentional for the whole 12 seconds, ie he kept running it until the nose got back to 15 degrees and by then it was too late as a rapid pitch down was inevitable.
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Old 21st Apr 2016, 11:19
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So, what caused the aircraft to go into a dive?

Here is the answer:

... the FDR recorded a nose down stabilizer input from the stabilizer trim switch of the control wheel lasting 12 seconds
So, that hypothesis by Denis Okan, in the form of the simulator video, has turned out to be deadly accurate. He ran the trim for 11 seconds (with flaps 10).

And the bank angle? Denis couldn't get the same negative G effects in the simulator, so he had to roll on the bank deliberately. On the actual flight, the trauma of the negative G may have caused one of the pilots to grab at the wheel, possibly catching one horn and inducing the roll.
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Old 21st Apr 2016, 11:30
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Ref post #1355 http://www.pprune.org/rumours-news/5...ml#post9351338,

...Good commercial strategy? Of course not, but it keeps the shareholders happy.

ST
A very sad commentary on the state of our profession.
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Old 21st Apr 2016, 11:57
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What stoped the trim after 12s, did the PF release the Trim switches or did the comtroll collum activated stab trim coutout switches kicked in when he started to pull? Und
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Old 21st Apr 2016, 18:23
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Originally Posted by RAT 5
At a height of 900 m there was a simultaneous control column nose down input and stabilizer nose down deflection from -2,5 deg (6,5 units) to +2,5 deg (1,5 units) (the FDR recorded a nose down stabilizer input from the stabilizer trim switch of the control wheel lasting 12 seconds, while the CVR record contains a specific noise of rotation of the trim wheels located on both sides of the central pedestal), as a result the aircraft, having climbed to about 1000 m, turned into descent with negative vertical acceleration of -1g.

I still think the answer lies in that quote.
If they pulled -1g to gain the level-off altitude,


I know what you mean, but 'pushed' might be more appropriate. But, moving on: I've read that the CVR recorded the captain's concern as to whether 8000 was set in MCP and the F/O's reply that "yes, here it is." If that was indeed the case why was there a control input at 900m to level off? The FD & HUD would still have been in TOGA climb to 8000. And for anyone to hold the pitch trim for 12 secs is unthinkable unless they were in a frozen state of panic. Both these guys had 1000's of hours and therefore I hope were competent & experienced.
I have been in a rapid climb, nose high, high speed ALT ACQ situation (B757) and reducing power was the game saver as the attitude was rapidly reduced, not trim.
Why level off prematurely would be more to the point. Could this not be the first in the causal chain. Given what appears to be on the face of it, a big heave- ho to arrest the climb in a hurry, an evasive manoeuvre, what could they have possibly been trying to avoid. I would suggest heavy weather seems the most obvious.
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Old 21st Apr 2016, 19:13
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Why level off prematurely would be more to the point.

That was precisely my question.
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Old 21st Apr 2016, 20:49
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Why level off prematurely would be more to the point. Could this not be the first in the causal chain. Given what appears to be on the face of it, a big heave- ho to arrest the climb in a hurry, an evasive manoeuvre, what could they have possibly been trying to avoid. I would suggest heavy weather seems the most obvious.
I don't think he was trying to level off, I think he either had, or perceived he had an excessive pitch attitude. Whether that was because of somotogravic illusion or an actual high pitch attitude or a combination of both who knows. I think his goal was to remedy a situation of high pitch while in a state of sensory confusion.
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Old 21st Apr 2016, 22:47
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Why level off prematurely would be more to the point.

That was precisely my question.
Does Tower cleared them for FL80? I think not.
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Old 21st Apr 2016, 23:51
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In the report it states that the flaps automatically retracted from F15 to 10 due to increasing speed. Is anyone else puzzled by this or is it just me? The only automatic flap retraction I am aware of is the blowback protection for Flaps 30 and 40. Anyone care to comment?
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Old 22nd Apr 2016, 00:46
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The 737-800s operated by my company have load relief at 10, 15, 25, 30, and 40 flap positions. At flaps 15 the flaps will move to 10 if airspeed reaches 201 knots.

These airplanes have the short field performance feature, where the leading edge devices do not fully extend until more than flaps 25 is selected.

737-800 that I flew at a previous carrier ten years ago did not have this feature nor the load relief at flap positions other than 30 or 40.
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Old 22nd Apr 2016, 04:31
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FZ has the short field performance version. The flap load relief is standard.

As for the level off, it was predicted a number of times earlier in the thread that this could be related to the missed approach altitude coded into the FMC. It is entirely possible that this was not deleted or overwritten to match the MCP selected altitude, and the FMC altitude would be giving flight director guidance and potentially confusing further an already confusing situation.
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Old 22nd Apr 2016, 06:15
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As for the level off, it was predicted a number of times earlier in the thread that this could be related to the missed approach altitude coded into the FMC. It is entirely possible that this was not deleted or overwritten to match the MCP selected altitude, and the FMC altitude would be giving flight director guidance and potentially confusing further an already confusing situation.
No this doesn't make sense, VNAV would have to be engaged which is highly unlikely. Even if VNAV was used for the approach, and TOGA not pressed, the FD would have been pitching all the way down as soon as the aircraft climbed away from the approach path until the MAP.
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