Undoubtedly, the Tu-154 is the most successful Russian mainline jetliner ever built. About one thousand copies were built at Samara aviation plant. About three hundred are still in service with airlines and various government structures. The Tu-154M, the latest version, is one of the most reliable and maintainable jetliner ever produced.

At the same time, for many unfamiliar people in the West the legendary tri-jet the airplane often associates with the Soviet civil aviation, and its notorious shortage of attention to passenger comfort. But most of those who actually piloted these big Tupolev love them and trust them. Every new case with the Tu-154 sparks up discussions in the Russian (and international) aviation community, not just about that particular case but also the ways the Russian (and world’s) aviation shall develop.

This makes it all the more difficult for us to unemotionally describe what happened to the Flight 372, - but we’ll try.

The RA-85744, manufacturer’s serial number MSN 92A927 was built in 1993 and underwent overhaul in 2009. This means that by the international aviation standards the RA-85744 falls right in the middle of the “middle aged” group of jetliners.

Captain Zakarzhe Zakarzhaev with about 17,000 flying hours of flight time is by any standard a very experienced airline pilot. His inferiors Marat Kimlaev and Magomed Shalamov are experienced aviators also. On Saturday, 4 December they had to make one more flight on the route they flew daily, linking Moscow Vnukovo airport with the capital of Dagestan republic, Makhachkala, whose airport is the main base for Dagestan Airlines.

That day 169 people boarded the airplane, including nine crew members (these figures are yet to be confirmed – one governmental source claims 163 passengers and 9 crews were on board, other says about 160 and 8 respectively). Finally, only fifty of them did reach their final destination the next day, aboard of another Tu-154M sent specially for them by Dagestan Airlines. Two people died in the incident, and 82 were hospitalized, including two children. About fifty remained in hospitals as of noon of December 6.

The crew started engines at 14:00 Moscow time, December 4. Eight minutes later the airplane was airborne, eagerly devouring aviation kerosene. The airplane carried 19.5 tons of fuel inside of its inner volumes. Air traffic controllers instructed the crew to attain 10,100m altitude for cruise, with a rider they will later be cleared for 11,100m after “everything is arranged”.

At height of some 6,500m “insufficient fuel supply” to the engines was reported. Warning lights “engine malfunction” and “low fuel pressure” came on. At the altitude of 8,600m the engines began working “unstably”. While the airplane was at 9,000 meters and still gaining altitude, one of the engines flamed out. It happened to be No.3 engine.

The crew reported this to the ground, asking permission for return back to Vnukovo. Another side engine, No.1, flamed out 50 seconds later. Immediately the decision was made to land at closest airport, which happen to be Domodedovo, some 80 km off.

The airplane descended on one (central) engine (no. 2). But it “was working inadequately”, the crew recalls. “After the engines flamed out, we set flaps at 28 degrees, and although that was not 60 degrees normally selected for landing, we could maintain safe speed of 400km per hour. So, the airplane did not go into stall but rather descended towards Domodedovo”.

Since the central engine worked at low thrust setting and unstably, the pressure in the hydrolics system was low, so loading on the flight controls was high. When the airplane was closing the airport, electric power generators failed, leaving the crew without vital navigation information. Radio continued working, and air traffic controllers regularly updated the crew on their positioning, vectoring them to the runway. According to investigators, the center engine “returned to normal functioning” prior to touchdown.

Low clouds hided Domodedovo’s runways from pilots’ eyes until they emerged from below the clouds. The crew recalls that when they saw the airport, they appeared to be crossing the runway No.1 at almost 90 degree angle. The situation required quick action, and the captain made decision without hesitation. He executed a hard turn to arrange the aircraft main axis with that of the runway centerline, turning as hard as the control forces allowed.

“We made a hard turn, but overflew and had to touch down at an angle [to the runway’s centerline]”, one of the pilot recalls. The airplane touched down on the right safety strip, crossed the runway No.1 and continued onto left safety strip.

The airplane overflew and touched down at a high speed with its flaps set at 28 degrees instead of 60 prescribed for landing. The RA-85744 came off safety strip at some 200 km/h, its nose strut went off, and then wings. The fuselage came to a halt after hitting a small hump not far from a concrete wall further down the way. Nose section came off and its top stopped moving less than 10m to the aerodrome fence.

Crash landing happened at 14:40 Moscow time. To get off the wracks, passengers had to jump to the height of 3-4 meters, and some were injured in the process. Airport rescue teams soon reached the place and helped evacuation.

The investigators say have so far questioned over one hundred other people. But they need more time to come to a conclusion about the main cause for the sequential engine failure. One of the possible causes is said to be crew error, as though the pilots “forgot” to turn on fuel pumps, and so the engines flamed out after feed tanks got empty. It is further said that the one remaining engine functioned unstably due to a mix of fuel and air in the feed tanks.

Another suggestion is a close circuit somewhere in the electrical system. Close circuit is suspected due to the fact that some navigation instruments failed during flight.

Surviving pilot Magomed Shamalov played down earlier voiced accusations of the RA-85744’s crews by saying: “We did not die, and that’s the main thing. It is going to be difficult for them to place on us the burden of the accusations [of the crash]”.

The pilot has his own view on what had happened. In a brief interview given in the hospital he was placed in after landing, he said he suspects the sequential engine failures might have been caused “if they had not added Arktik into the fuel”. The Arktik is an addition into fuel preventing formation of ice crystals in it. These crystals build up when the airplane flies at high altitudes, where ambient temperature is much lower.

Investigators say they will voice their conclusion to what happened to the Flight 372 after the airplane’s flight recorders are decoded and the wracks of the RA-85744 carefully studied.

Meantime, with one more TU-154M lost with two people dead, the inevitable end of the Tupolev tri-jet’s career draws closer. All horses die, even they are good, reliable workhorses.