The problem with the sensors: experts have proposed a new version of the Tu-154 crash


Version of the crash of Tu-154 plane near Sochi because of problems with flaps appeared after the publication in the media of transcripts of negotiations of crew with the flight recorder on Tuesday evening, December 27. In this case, the collapse of the liner could occur due to non-synchronous retracting the flaps, suggested a number of experts after the appearance of transcripts. The resulting difference in lift of the wings could cause the plane to crash.

With this version of the conversation did not agree with the honored test pilot of the USSR Viktor Zabolotsky. He stressed that in the control system of flaps provides a mechanism for synchronization of their movement. “If the flaps started to move asynchronously, work automation, which would stop their production or the cleaning,” — said the expert.

The flap is deflectable element mechanization of the wing, located on its rear edge. It is designed to improve the bearing capacity of the wing during takeoff, climb, descent, and landing. The flaps will use when flying at low speeds. With the release of the flaps increase the wing area and curvature of its profile, thereby increasing the lifting force of the wing. After the decoding of negotiations of crew members who have mentioned problems with the flaps, some experts have suggested that one of the pilots could confuse the controls on the dashboard and instead of the lever of the flap control push the release handle to the chassis.

However, Deputy chief editor of the magazine “Aviapanorama”, honored military pilot of Russia Vladimir Popov told to mix control knobs, gear and flaps Tu-154 is impossible: the different levers, and they are not there.

Error signals

Zabolotskaya put forward the version according to which the cause of the disaster became a false statement of height and speed on the devices. He explained that to identify these parameters on the Tu-154 has installed a system of air signals SVS-72. It consists of receivers, dynamic and static pressure. If you happened to fail, the pilots could not adequately assess the speed characteristics of their aircraft.

“In such a situation after the separation of the aircraft from the runway the speed reading will begin to grow faster than normal — the actual speed will be less than the instrument. In this case, the pilot starts to raise the nose of the aircraft, translating it into a set of heights,” said Zabolotskaya.

Receiving incorrect speed information, the pilot can start the transfer of the aircraft into a climb that would lead to the release of the supercritical angle of attack (the plane is “bucked”) and the stalling.

Opinion Zabolotskaya divided Popov, adding that such a waiver could be a prerequisite of the disaster. “Maybe he’s right. One failure usually does not lead to disaster or accident. But when there are several superimposed, then it leads to the collapse of the information on the crew if time is short. And to cope with the situation of the person becomes impossible.”

With this version of agree, and former designer of OKB “Dry” Vadim Lukashevich. “If the pilots did not know the true speed, then their actions it is not consistent”, — he said .

Waiting for the insights

Thursday, December 29, there will be a briefing by the Minister of transport of Russia Maxim Sokolov, on which, perhaps, will be announced the preliminary results of decoding the speech and parametrical recorders of the crashed plane.

The final conclusion on the accident can wait at least six months, but preliminary conclusions may appear within weeks, said the chief editor of “Air.ru” the novel of hussars.

According to him, the findings of the investigation will largely hinge on the testimony of the parametric recorder, which records technical information: flap position, speed, engine rpm and so on.

“If not removed the flaps, because of the huge resistance the plane nose up and falls. And if all were implemented by regular and with flaps, but the plane suddenly lost control, that version will be studied further,” says Gusarov. Comparing these data, it is possible to reconstruct the spatial position of the vessel and determine the causes of the crash. He Gusarov considers equivalent to the most likely version of a technical malfunction and pilot error.

“If the Commission will see that the flaps were not removed at the right time and left simultaneously, then it is clear error [of the pilot]. And if everything was run normally, but the plane lost control, so will be the details and the second to study all phases of flight”.

A DoD sniffer plane Tu-154 flying to Syria, disappeared from radar on Sunday morning, December 25, a few minutes after departure from Sochi. On Board were 92 people, including soldiers, journalists, song and dance ensemble of the Alexandrov and the head of the Fund “Fair aid” Elizabeth Glinka. The crashed into the Black sea near the Sochi coast. All crew members and passengers died. On Wednesday, divers raised from the bottom of the second flight recorder, the search of fragments of the plane and bodies.

On Wednesday, Minister of defense Sergei Shoigu announced the beginning of payments of financial assistance to the families of those killed in the crash of Tu-154 over the Black sea. The defense Minister at the meeting of the public Council under the Ministry of defense called the size of payments every family of 5.8 million rubles. Shoigu said that the defense Ministry works with the families of those killed in the plane crash: “we are Talking about the fate of children, wives, on housing conditions”.

The Minister of defence also said that after the New year will open a competition for a new set part of the Alexandrov ensemble, whose members died in the crash.

The history of disasters

Because of the actions of the crew

17 Nov 2013 a passenger plane Boeing-737 of airline “Tatarstan”, flying from Moscow, crashed while landing at Kazan airport. The causes of the crash by the interstate aviation Committee (MAK) said the problems with the system of safety management in airlines and deficiencies in the crew.

11 Sep 2012 the plane An-28 on the flight Petropavlovsk-Kamchatsky — Palana crashed near the village of Palana. The cause of the accident in Mack acknowledged the violation by the crew of the schematic approach, in the blood of both pilots were detected alcohol.

2 APR 2012 the plane ATR-72 airlines UTair flying from Tyumen to Surgut fell on takeoff from the airport. The cause of the accident in Mack cited the refusal of the commander of the aircraft from icing. This has led to the stalling of the aircraft at takeoff, making the crew failed to timely recognize the problem.

September 7, 2011 near Yaroslavl the plane fell Yak-42 hockey team “Lokomotiv” on Board. From the report of the IAC, it follows that the cause of the accident the mistakes of the crew, involuntarily aimasho on the brake pedal during the run.

20 Jun 2011 the plane Tu-134 of airline “Ruseyr”, flying from Moscow to Petrozavodsk, in adverse weather conditions made a hard landing on a highway near Petrozavodsk airport. During landing there was a fire. The reasons for the disaster in the Mac stated that the crew not decided to go to the second round, a reduction of unsafe height in the absence of visual contact with ground reference points, as well as slight alcohol intoxication of the Navigator.

Due to a technical fault

3 January 1994, a Tu-154, carrying out flight from Irkutsk to Moscow, lost control and crashed near Irkutsk, after he fired up the engine. The Commission of inquiry established that the engine of the crashed plane was denied not for the first time, before flying at his work complained.

July 22, 2002, the Il-86 aircraft, carrying out flight St. Petersburg- Moscow — Sochi — Moscow — St. Petersburg, crashed in the suburbs a few seconds after takeoff. As the main version in the investigation of the IAC considered the spontaneous transition of the horizontal tail fins in an extreme position. As a result, the Mac recognized the mistakes of the pilots.

19 November 2001, the Il-18V, flying from Khatanga to Moscow, crashed in the Tver region. The most likely cause of power called spontaneous deviation of the trimmer of the Elevator on a dive, caused by a combination of technical factors.

On March 18, 1997 plane An-24 flying from Stavropol to Trabzon (Turkey), crashed in area of Cherkessk. The cause of the incident described the destruction in flight the rear fuselage due to a buildup of corrosion fatigue damage.

6 Dec 1995 the Tu-154 flying from Khabarovsk to Yuzhno-Sakhalinsk, crashed into a mountain at 274 km from Khabarovsk. The cause of the accident was named as the actions of the crew and technical malfunction. Among the technical factors was identified as a reduction in the effectiveness of alarm, which the crew was unable to react to a dangerous situation.

With the participation of Philip Aleksenko

 

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