Weather
 

Pic of aircraft on ground in Sochi shows wet snow. Anyone have the METAR for that night? De icing issue?

The final position gave us a new stone to mosaic:

The plane flew for ca. 10-11 km before crash - investigators told 6km south, then U turn and 4km north. They also told that the speed was approx. 350km/h and that there was lack of climb. It is not clear what exactly they meant by this lack of climb. Anyway, ATC lady instruct the crew to call Sochi approach after reaching 300m. They never did it. Investigators (not Kremlin) also supposed that it was technical issue and/or human error.

It looks that the key information is climb rate from airport radar data. If they found that climb rate was very low, they could exclude some reason, for example bomb.

Back door:
URSS 250230Z 06004MPS 9999 BKN033 OVC083 05/01 Q1019 R06/090070 R02/090070 NOSIG
RMK R02/05004MPS MT OBSC QFE763


Decoded:
Location...........: URSS
Day of month.......: 25
Time...............: 02:30 UTC
Wind...............: true direction = 060 degrees; speed = 4 m/s
Visibility.........: 10 km or more
Cloud coverage.....: broken (5 to 7 oktas) at 3300 feet above aerodrome level
Cloud coverage.....: overcast (8 oktas) at 8300 feet above aerodrome level
Temperature........: 05 degrees Celsius
Dewpoint...........: 01 degrees Celsius
QNH (msl pressure).: 1019 hPa
Next 2 hours.......: no significant changes

Well, official press-release already published stating that is was no military cargo on board. They said it was only luggage plus 150 kg of medical supply and food.

The "beach camera" pictures, I spent some time looking at google maps, the Imray nautical charts etc and I am fairly confident that the low green light shown on the video is at the end of the harbour wall on the Sochi Yacht Club, it is the only likely candidate. If you plot a line roughly looking up the beach at the angle shown in the video, then the light that appears in the sky briefly is in the correct alignment for the light on the harbour wall at the Port Of Sochi, which is elevated on a tower. The shape of the light and the distinct on/off is consistent with a nautical light rather than an explosion.

Pure speculation on my part: Possible misuse or lack of use of the engine anti icing systems? Potential freezing of tat probes in the engine inlets, leading to erroneous thrust settings and then resulting confusion. Might explain the lack of climb, as the crew may have reduced thrust to prevent an indicated overboost, which then led to an unrecoverable stall...

From historical perspectives Air Florida and the DC8 at Gander come to mind.

One can take off but not climb.

I'm not sure if it matches the other cold weather event of Continental at Denver. I'm quite sure that the TU has lots of experience in cold weather but perhaps some history might pop up on this board

Does it have slats for takeoff to increase its tolerance to wing icing?? or does the weather at Sochi preclude any discussion in this?

Not quite the full story. I flew with a captain who had 10,000 hours on Tu-154s. Although he liked the tough airframe, it required yaw-dampers, pitch-dampers, and roll-dampers to keep it flying (a by-product of anhedral and other idiosyncratic designs). They had to practice damper off flying in the real aircraft, and he said it was utterly uncontrolable. You might get away with a visual, but could not follow an ILS.

In fact, Tu-154 damper off flying is somewhat reminiscent of that Liveleak video in comment #68. Great video, I have to say. Would hate to think what that looked and felt like, in the cockpit ! Good airmanship to fly it around a bit, and get a feel of the instability, before landing.

Operation near freezing temps is not unknown for ru operators. So I would assume a more sudden event. With the relative light TOW they should be able to climb on two engines.

@paperHanger my nephew (also a pilot, russian-born wife) is very familiar with the area and concurs with your suspicion.

Weather then was about -4 C with moderate snowing. Here in Sochi it was +8 C at takeoff, no precipitation at all, not very comparable weather scenarios.

Actually - cold temperature, by itself, helps with both - takeoff and climbing.

The media found another witness who was allegedly out on a boat and described the plane descending as if trying a water landing. The forward speed was slow and it was in an "unnatural" nose up position. It hit tail first which broke off and quickly sank.

Deep stall perhaps?

@unworry ... also, the crash site is South-East of Sochi ... the webcam footage, if it is from Sochi Beach, is looking North West ... 180 degrees away from the crash site ..

@vovachan if it had come in slow and nose up, it is unlikey to have broken up ... the TU154 is very solid bit of kit, a slow water landing would have been very survivable, at least a few passengers would have managed to get lifejackets on even if the tail broke off, in front of the rear bulkhead. The fact that no one survived and the authorities insist no one had a life jacket deployed would suggest it either broke up mid air, or entered the water at some reasonably high velocity.

Perhaps you forget AF447. That hit the water at a forward speed of 107 knots and nose-up pitch of 16.2 degrees. It was not "very survivable". Had we seen it, I think we'd have thought it to have a low forward speed and to be in an unnatural nose up position.

IF the eyewitness report is a cousin of the truth, I think Oakape's suggestion of deep stall has merit. Of course eyewitness reports may be correct, far off the mark, or anywhere between

Not sure that in the realities of present-day Russia it's practical to separate the two. Thankfully tho it's hard to control all info these days from one central source of political power. Even it being the Kremlin.
Anyway thank you for you concise and clear postings in this thread.

BTW it's reported that the BLACK BOX IS FOUND. ????: ???????????? - ????????: ????????? ?????? ???? ??-154 ? ???? ???? ???????? (in Russian)
A source told TASS state news agency that 1 of the flight recorders has been located, yet to be lifted. It doesn't specify which one it is, and says it's currently unknown how badly it was damaged. However it does state that it was found "under the plane's cockpit" adding that the other *two* are believed to be in the tail part.

Lack of climb could be an instrumentation problem.
Does anyone know if this was a 'steam gauge' type aircraft?
Were the vertical references actual spinning gyros?

Vertical speed makes a world of difference.

No, radar readings from a ground station.

Flight data recorder has been recovered

Russian plane crash: First black box located in the sea - BBC News

It looks like it. And reason? Too early flaps retraction? In the same time, the HS have to be set into flight position. Failure, not in auto position? TOW and CG near limits?

One bit I have been musing about is the time of the accident, 0540 in the morning after they already had done a night flight from Moscow. Not the best for fatigue.

Karel, if anything is not set as required on the TU before take off, it will give you a config warning and the take off light won't go out. I'd be very surprised if the stab had not been set as required, of course if that was true, then we'd have a major suspect.

CG is regulated via fuel in the TU, so it should not have been a problem, but of course, who knows.

CAnt the TU154 make it Moscow to Syria non stop? It seems with such a light load a refuelling stop is a bit pointless. Could it perhaps have picked up some cargo in Sochi?

TASS reporting this morning quoting unnamed sorces (quoted by another source, for all that's worth..) that the FDR has been found, and that the most favored theory at present is 'engines ingested some foreign objects causing damage'. Multiple birdstrike... ?

Tu-154 plane’s flight data recorder recovered from water
The black box will soon be taken to Moscow for deciphering, according to the Russian Defense Ministry
© Artur Lebedev/TASS

MOSCOW, December 27. /TASS/. The flight data recorder of the Tu-154 plane of the Russian Defense Ministry that crashed in the Black Sea on Sunday has been pulled from the water, a law enforcement source told TASS. The Russian Defense Ministry confirmed later that the black box had been recovered from the water.

"The parameter flight data recorder has been recovered from the water. The plane with the black box will soon depart from Sochi to Moscow where it will be deciphered by specialists of the Defense Ministry," the source said.

-50%
TASS: World - Tu-154 plane?s flight data recorder recovered from water

BBC radio reporting all Tu-154 flights suspended until further notice..........

At night ? maybe bats ..:hmm:

Yes, it is possible. Astronomers often observes migration birds at night pictures. TU5 has 3 engines and a loss of one of them should not be fatal. Uncontained failure? Multiple engine failure?

Geese are well known to fly at night. And seldom alone. Don't know if Sochi is far enough south for this to be likely this time of year. We'll soon know.
As regards the discussion about refuelling, it may make sense to round-trip it with cheap, readily available Russian fuel if uploading in Syria might be a lottery.
Again, not saying this is the case.

Bird strike ?

ATC `s remark was in the classic McEnroe style of "man you cannot be serious". To add to which mine would have been, as it was not Halloween witches riding on broomsticks may also be crossed off the list of probable cause.

Wonder if de-icing was needed and not done?

About de-icing...

Sochi is a resort city, on approximately the same latitude as Rome. Palm trees grow there. This should give you an idea about the climate.

ETA: Yes, they had the Winter Olympics. Speaks more of corruption than appropriate climate imho.

Mr Snuggles it's also where they held the last Winter Olympics. Typical Central Continental climate - hot summers and cold winters.

Post 17 has temperature +8 so forget that.

I live in Bucharest, other side of the Black Sea and only a little bit further north than Sochi. It's been a remarkably mild winter so far, very little precipitation (a day or two of snow at most that I recall), low single digits in the day and low (or should I say high?!) negative single digits at night right now. I fly out of Otopeni on average at least once a week if not twice and I don't remember seeing the deicers out yet this year.

(By contrast, two years ago it was around -15/-20 by mid December, which is if anything more normal. Last year's December was also mild but we paid for it with blizzards in an absolutely horrible freezing January and a somewhat rubbish spring...)



On the last point, I'm sure you'll not be surprised to learn that the weather at sea level and the weather a few thousand feet up a mountain can be somewhat different. Many of my friends are spending this time of year skiing in the Carpathians despite the mild winter down on the ground.

There are about 50 or so in operation, all by various gov agencies I think. Civ fleet must have been retired for some years by now. So on its own it's a non-issue.

Flight Plan Route
 

Im wondering why they stopped in Sochi?

I looked up the flight plan yesterday (forgot to copy will check tomorrow)its intended routing was in fact NOT a southerly route.
It was due to route East to avoid Georgian FIR-Azerbaijan FIR before heading south into Iran FIR then west into Iraq FIR finaly into Syrian FIR.
It was efectively due to fly east to route joining from the southerly position of the earlier plotted FR24 example.

https://www.flightradar24.com/data/a...-85041#bef9574

Another TU-154 followed the sameroute dep URSS at 1500ish UTC.
RA-85072 was due to depart at 2310UTC but did not depart till after 0220UTC

Refueling ´planned in Mozdok
 

The refueling was planned for Mozdok but was changed to Sochi due to bad Wx at Mozdok.
https://sputniknews.com/russia/20161...terror-attack/

Happened very quickly after takeoff - unlikely to have been a party - possible engine failure, decided to turnbachk and stalled it.............

Why would they need to refuel at Mozdok, only 80 minutes or so out of Moscow?