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-   -   Yak42 crash, Russia (https://www.pprune.org/rumours-news/463030-yak42-crash-russia.html)

henra 9th Sep 2011 18:15

This accident is in so far puzzling to me as with such a small bird on such a long runway, why didn't they reject ???
Normally that thing should have rotated halfway down the Runway. If in such a small Jet Airliner after 1500m the speed is far insufficient for takeoff, something is awfully worng.
That would leave ample opportunity to rethink and throw out the anchor.
why did they continue?
What was their speed at 1500m point ? 80 kts? or less?

SLF305 9th Sep 2011 18:18

Camera Location - Further Thoughts
 
The shadow of the right wing appears very close to the mentioned fenceline at left. Has the aircraft already veered right of centerline?
The camera likely got whacked by the aircraft based on the last frame. Was the camera mounted on the mast (antenna) that was struck?
Again, just food for thought?

Kulverstukas 9th Sep 2011 18:38


It appears the camera was not at ground level but elevated about 4 feet (just an estimate ???). Looking at the fenceline to the left adds to that impression. The foreground also appears like a grassy unprepared surface. Was this camera located on the extended runway centerline past the end of the runway or perhaps off to the side?
This is CCTV camera located at same pole which support beacon at the end of runway and which was hit at the end of the run by plane.


The camera likely got whacked by the aircraft based on the last frame. Was the camera mounted on the mast (antenna) that was struck?
Exactly.

Kulverstukas 9th Sep 2011 19:19

http://img-fotki.yandex.ru/get/4204/...14f6a9_-1-orig

Machaca 9th Sep 2011 21:44

They went off the far end in the above photo.

ensco 9th Sep 2011 21:58

Could load distribution have played a role? Hockey players are large men, usually weighing over 90 kilos.

fdr 9th Sep 2011 22:20

Not Spanair
 

Yes, clearly visible on the video. Slats/flaps extend together, unless there is a malfunction (with associated warnings) you cannot have flaps 20 without extended slats. This accident seems to have nothing in common with Spanair.
Quite.

Spanair's JK5022 MD-82 reaches Vr in a shorter distance than a normal aircraft does due to the lower drag.... it just doesn't fly well without LE devices, and TE Flaps. Now there is still a possibility of the unique takeoff mechanism used by at least one peninsula airline.... where following a config warning for flaps being forgotten, then the flaps are deployed on the roll. (what the passengers don't see apparently doesn't always hurt them). The first event like that, the crew achieved the flaps by the normal Vr (well, almost...) the second/repeat event ("just bad luck, could happen to anyone..."), resulted in the rotate being delayed by about 30kts... so the roll was much longer than normal. Again, Spanair, the flap configuration was not identified before the rotate was initiated, and the aircraft immediately enters a high drag condition with inadequate lift, and exhibits roll instability... Yaroslavl is not a repeat of Spanair.

The YAK-42 has not rotated as it overruns the DER, yet the video shows the aircraft responds normally to elevator input at least at the time of impact. The stabiliser if initially mis-set takes time to be recognised, and reset, and would result in an increase in TO roll...

The event is either a failure to achieve adequate speed, ie low thrust or high drag from wheels... or is an mis-set stabiliser. If the report of the stabiliser trim setting being correct is actually valid, then the engine performance/fuel etc is going to be interesting to look at. Brakes as well...

MountainBear 10th Sep 2011 04:36


New Video out of crash scene.

Kulverstukas 10th Sep 2011 09:11

Tires on fire and in 1 meter undamaged wheel with no sign of fire. Brakes set at take-off?

PS: Fuel quality confirmed today as said by Rosaviation representative.

So, not bad fuel, not non-takeoff configuration, not "half runway takeoff"...

The Ancient Geek 10th Sep 2011 09:51

Maybe incorrectly loaded with extreme forward CofG ?

Kulverstukas 10th Sep 2011 09:58

As was mentioned on forumavia.ru, this is VIP configuration with salon with couches and tables in the wing section and rows in the tail. Everybody must be on the rows and buckled at takeoff and landing, so it's highly improbable, I think.

Bleedvalve 10th Sep 2011 11:27

That looks like the left hand bogey burning there. Did they go off the runway to the left or the right?
Sticky brakes or park brakes set looks like a possible cause.

Hotel Tango 10th Sep 2011 11:49

Good to see all the armchair experts are here again. Bleedvalve, the answer to your question

Did they go off the runway to the left or the right?
is in the above photo of the airport if you bothered to use your brain for two seconds!

Kulverstukas 10th Sep 2011 13:58

Another "expert" - custom officer from Tunoshna. What's important - confirmed that Yak reached runway from taxiway #5.


ron83 10th Sep 2011 16:19


Yak reached runway from taxiway #1.
They departed RWY 23,so it should be Taxiway 5 they line-up at:hmm:

RegDep 10th Sep 2011 16:30

Taxiway 5 and ILS Localizer circled.

http://i1103.photobucket.com/albums/..._aerodrome.jpg

Kulverstukas 10th Sep 2011 18:43

Thanks for correction. Besides, this video must put stop on speculations about "halfway takeoff".

silverstrata 10th Sep 2011 18:54


that the moment the aircraft left the prepared surface and continued to roll out on the grass? The nose gear is clearly off the ground, viewed directly and by it's shadow on the ground but the main gear are still on the ground (or grass).

Yes, interesting video. That certainly looks like grass to me.

There are tyre tracks to the left that look a lot more like impressions in grass, and the take off zone has none of the lights and lines of a runway. It would certainly appear like a take off on the grass.

Incorrect power setting? Too great a de-rate?

Actually, the most likely scenario to me is brakes binding. The primary thing that caught fire in the lake was the entire wheel bogey. But why? Fuel spillage on the tyres is possible, but this was the only fire I could see. More likely is that the the brakes and tyres were glowing white hot, and burst into flames. It would explain the overrun and the fire.



.

jcjeant 10th Sep 2011 20:20

Hi,


that the the brakes and tyres were glowing white hot, and burst into flames. It would explain the overrun and the fire.
Maybe ..
Despite .. on the video (latest frames) it's a clear view of the right main landing gear and nose wheels gear .. and it's no fume .. smoke visible ...

silverstrata 10th Sep 2011 20:35


Despite .. on the video (latest frames) it's a clear view of the right main landing gear and nose wheels gear .. and it's no fume .. smoke visible ...

True.

Although we only have a view of the sbd gear on that take-off video, and it is unclear which bogey is burning.

But there again, the aircraft appears to have veered right, not left.


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