Accident of Tu-134 in Nakhichevan

Tu-134B with registration number 65703 (factory - 63383, serial - 59-02) was released by the Kharkov Aviation Plant on August 28, 1980 and then transferred to the Ministry of Civil Aviation , which has already sent the airliner to the 1st Riga United Aviation Division of the Civil Aviation Authority of Latvia, and on July 20, 1982, he was transferred to the Baku joint squadron of the Azerbaijan Civil Aviation Administration. After the collapse of the USSR and the liquidation of the Ministry of Civil Aviation, the side of 65703 on September 23, 1993 passed to the Azerbaijani AZAL , which is part of the Azerbaijan Khava Yollari concern . On November 23, 1994, the D-30 3-series engines were delivered to the aircraft, that is, the model of the airliner changed to a Tu-134B -1 . The last repair of board 63383 took place on March 30, 1993 at plant No. 407 of Civil Aviation ( Minsk ), and in total it underwent 8 repairs. With a designated resource of 35 thousand flight hours and 20 thousand landings, the plane at the time of the disaster had 27,500 hours and 29 minutes of raid and 17,893 landings, after the last repair - 4495 hours and 25 minutes of flight time and 2,685 landings ^{[1] [3]} .

Engines

At the time of the crash, the aircraft was equipped with two 3-series D-30 turbojet engines.

Among the comments on the engines worth noting entry in the logbook for November 20, 1995 : "When you turn on the air conditioning system, there is the smell of oil burning." After that, aircraft technicians at Bina Airport completed a list of activities to identify the cause and eliminate the defect, but could not identify it and eliminate it. Further, until November 27, the aircraft 65703 made 19 flights, in which, when a burning smell appeared, the crew reduced the air from the engines ^[1] .

November 27 in the logbook appeared re-record of the presence of burning smell in the cabin. After this, during the work, it was found out that the cause of this odor was a malfunction of the left engine, or part of the air conditioning and selection system associated with the left engine. On December 2, additional work was carried out to eliminate the defect “The smell of burning in the cockpit”, after which the entry “No comments” appeared in the logbook, which was next to the crossed out entry “The smell of burning insignificant”. Also on November 30, a telegram was sent to the Bykovsky Aircraft Repair Plant ( Moscow ), in which a plant representative was called in to file a complaint and repair the defect. In response, on December 5, a telegram arrived, in which there was a request for the presentation of additional information on the manifestations of the defect and the results of the inspections, in particular, it was requested whether the flame tubes were inspected ^[1] .

A day before the crash, the plane made 5 flights, but there were no observations about the presence of burning smell in the cabin and in the passenger cabin. From November 20 (the first record of the smell of burning) and until December 5, 1995 (catastrophe), the plane completed 30 flight hours ^[1] .

The commander of the aircraft (FAC) - 39-year-old pilot 1st classGA Edward Halilovich Hasanov. In 1975, he graduated from Krasnokutsk LUGA , where he received specialized secondary education, and in 1988, under the Ulyanovsk Center, the CMEA GA was retrained to Tu-134. The total raid was 9534 hours, of which the Tu-134 was 3641 hours, including 1,478 hours as a commander. The flying time in 1995 was 333 hours, including 143 hours at night. Was allowed to fly on the 1st category of meteorological minimum (60 by 800 meters). Previously, no accidents and incidents. At the time of the crash, it worked 5 hours and 30 minutes, of which 1 hour and 11 minutes were flying ^[1] .

The co - pilot is a 30-year-old pilot of the 3rd class GA Sergey Georgievich Kuliev. In 1985, he graduated from Sasovskoye LUGA , where he received specialized secondary education, then at the State Technical Training Center the State Concern was retrained according to the program of the Tu-134 commander. The total flight time was 4557 hours, of which the Tu-134 was 264 hours, including 120 hours at night. For flight work was suitable without restrictions. Previously, accidents and incidents did not have ^[1] .

Navigator- instructor - 35-year-old navigator of the 3rd class GA Sergei Vladimirovich Shamov. In 1982 he graduated from the Caspian Naval School , where he received a higher education, and in 1994 he was retrained in the UAC. The total flight time was 623 hours, all on the Tu-134. The flying time in 1995 was 491 hours, including 240 hours at night ^[1] .

Mechanic - 31-year-old flight engineer of the 3rd class GA Alexander Vladimirovich Sokolov. In 1984, he graduated from Kirsanovskiy ATUGA , where he received specialized secondary education, and in 1992, in the Ulyanovsk Center, the CMEA GA retrained to Tu-134. Had a raid on the Tu-134 869 hours. The flying time in 1995 was 295 hours, including 130 hours at night. For flight work was suitable without restrictions. Previously, accidents and incidents did not have ^[1] .

According to the existing regulatory documents, the crew went through all kinds of preparations in full. In this structure in 1995, 50 flights were already performed. Professional training and flight experience corresponded to the level required to perform the flight task ^[1] .

Prior circumstances

The crew on this plane served flight A-55/56 on the route Baku - Nakhichevan- Baku. At 15:28 (UTC + 3), the Tu-134 flew out of Baku airport and at 16:37 landed at Nakhichevan airport . This stage of the flight passed without features, the crew did not have any comments on the operation of the units and systems of the aircraft. At 5:00 pm, the crew began to prepare for departure on the return flight (A-56). In total, there were 6 crew members (flight crew and two flight attendants ), 76 passengers (initially, the media mistakenly called 74 ^[4] ) and 1,380 kilograms of hand luggage and baggage. The tanks contained 7,500 liters of aviation fuel TS-1. The take-off weight of the documents was 44,300 kilograms, centering 24.6% of the MAR , that is, within the limits established by the RLE of the Tu-134. The crew launched the engines, and in the process of taxiing to the executive start performed all the necessary tests of the aircraft systems. In this case, there were no deviations that could interfere with the takeoff ^[1] .

Engine Failure

At 17:52:09 (hereinafter, this point in time was taken as the beginning of the countdown), after dark, the commander reported to the dispatcher about readiness, for which he received permission to take off. Takeoff was performed by the co-pilot. On the 26th second The thrusters of both engines were put into takeoff mode. The take-off was carried out without significant remarks, only slightly exceeded the front-wheel lift (Vr) and tear-off speeds (V2), as well as the pitch angle, but this did not affect safety. After 3 seconds from the moment of separation from the band at 8-10 meters from it and at the instrumental speed of 317 km / h, the crew removed the chassis . At this moment, the temperature (3 ° per second) of gases behind the turbine of the left (No. 1) engine began to grow slowly. At the 86th second, with an instrument speed of 335 km / h and at an altitude of 60 meters, the left engine failed, while the gas temperature behind the turbine jumped to 680 ° C, the vibration velocity dropped sharply and the rotor speed fell in both stages. In the cockpit, a one-time command “Failure of generators of the 1st engine” worked, and the plane began to roll to the left. However, such commands as “Engine Fire”, “Dangerous Vibration”, “Minimum Oil Pressure”, “Oil Shavings” and “Reverse Enabled” did not sound. The board itself “Failure of generators of the 1st engine” was out of sight of the crew members, since the flight mechanic's seat was in the take-off and landing position ^[1] .

Due to engine failure, one of the arrows on the rotor speed indicator began to rotate rapidly on the middle instrument panel. The flight mechanic noticed all this in a timely manner, and then the captain felt a slowdown in the rate of growth. The co-pilot, who piloted the aircraft, spontaneously parried the left roll, deflected the elevator down (to dive), and the rudder to the right to create a coordinated steady slip ^[1] .

A flight mechanic mistakenly decided that the right engine had failed, and he reported to the captain. At the same time, it took him only 3 seconds to recognize the failed engine, whereas in fact this requires at least 5 seconds. In this situation, it is most likely that the flight mechanic was guided by a change in the position of the arrows of the engine control instruments without reading the values ​​of the instrument readings. This is due to the fact that the coaxial arrows of the left and right engines on the paired speed indicator of the rotors of the engines differ only in numbers 1 and 2, respectively, which are difficult to see at night. Another factor in this haste was the imperfection of the crew training method for actions in case of a fire on the engine, in which the main criterion for training is the time of its reaction to failure. In this situation, the flight mechanic suspected that a fire had occurred in the engine, and therefore in a stressful situation that had arisen, he made a hasty conclusion ^[1] .

When the captain heard about the failure of the right engine, he took control. By that time, the co-pilot had already managed to balance the plane to the new conditions of flight and felt that in fact the plane was turning not to the right, as if the right engine had failed, but to the left. But in this stressful situation, the co-pilot could not cross the psychological line and say that the flight engineer was probably mistaken. At the same time, the captain, before taking control, did not hold “softly” for the controls and did not control the actions of the second pilot. Subsequently, on the poll, he stated that he did not notice the aircraft turning around and did not feel the rudder deviation. On this occasion, it is worth noting that all the provisions of the RLE and the technology of the crew of the Tu-134 are designed to control the aircraft by the commander, and there are no indications about the redistribution of duties in the crew and changes in technology when piloting the second pilot ^[1] .

Total loss of thrust

Having accepted the wrong report of the mechanic on the failure of the right engine as the truth, the commander began to “continue” his mistake. At the 96th second of the flight, the airliner flew into smog , which began to shield the flare of the failed left engine, which was well marked at night. A train of flames was also observed by eyewitnesses. The commander took the resulting glow as a sign of a fire at the tail of the aircraft, and since he had previously received information about the failure of the right engine, he decided that the failed engine was on fire. In this regard, he gave the command to emergency shutdown of the right engine. Meanwhile, when the rotor rotates in the engine, and the temperature rises above the maximum permissible value, which in this case was observed by the flight mechanic, according to the RLE it is necessary to switch the engine to idle mode, let it work for two minutes and then turn it off. In this situation, the commander first gave the command to turn off the engine, and after 10 seconds gave the command to emergency shutdown. If the crew acted exactly on the RLE, then the flight mechanic had the opportunity to correct his mistake in identifying the failed power plant when detecting a drop in the engine speed ^[1] .

When the flight mechanic on command began to turn off the right engine by moving ROD , he saw on the tachometer that with this action the speed of the engine running began to fall. Realizing the mistake, after a couple of seconds, the flight mechanic returned the ROD to the working position, but by that time the working right engine was already stopped. For eight seconds, the flight mechanic probably interpreted the situation, and then at the 105th second he reported: “The refusal was complete, the second refused . ” After another couple of seconds, the vertical speed of an airliner located at an altitude of 197 meters dropped to zero, and the instrument speed dropped to 290 km / h. Having specified the information, the commander made the decision to carry out an emergency landing outside the aerodrome, which was reported to the dispatcher twice ^[1] .

Catastrophe

In the current emergency, the commander acted competently and maintained high performance. But ahead of the course there were residential quarters, so the commander turned the plane to the right, but with a roll of 36 °, instead of the maximum established 15 °. The Tu-134 quickly lost height and at 17:54 flying at the rate of 196 ° and falling with a vertical speed of 10 m / s, it crashed with the right wing into a plowed field. The airliner turned right to 19 ° (to 215 °) and it fell to the ground, after which the right wing of the wing collapsed, and the right engine also separated. The side-mounted fuselage crashed into the concrete base of the LEP-500 support, which caused the tail end and stabilizer to be torn off. After 180 meters from the place of the first touch of the earth, the destroyed plane stopped. Tu-134 fell on the southwestern outskirts of the city of Nakhichevan , 3,500 meters from the end of the runway and 800 meters to the right of its axis at an altitude of 800 meters above sea ​​level . A fire did not occur ^[1] .

An emergency and rescue team consisting of 20 people and 6 cars left the airport: two ambulances , two trucks , one fire and a crane . However, this team lost its orientation on the ground and arrived at the crash site only an hour later when the dead and wounded were already taken out by local authorities and military units. In total, 52 people died in the crash (at first, the media reported 48-49 dead ^{[5] [6]} ): the co-pilot, a flight attendant and 50 passengers (sitting in the central part) ^[1] . According to the number of victims, this plane crash on the territory of Azerbaijan is the largest since 1991 ^[2] and the third in the country's history in general (after the Il-76 disasters in 1989 and the An-24 in 1973 ) ^[7] .

The investigation of the disaster was carried out by a commission appointed by order No. 30 of December 6, 1995 of the Deputy Chairman of the Interstate Aviation Committee (IAC) and had the following composition ^[1] :

• Chairman - Deputy Head of the Aviation Accident Investigation Department at the IAC Air Transport Yu. V. Nastenko
• Deputy Chairman - Director of Azalavia Airlines Mukhtarov M. A.
• Commission members:
  • Deputy Head of the Field Investigation Department of the Interstate Aviation Committee Gordeyev Y. S .;
  • Head of the Scientific and Technical Center (STC) of the IAC Tsivilev F. S .;
  • Leading Design Engineer ASTC. A.N. Tupolev Korneichev A.N .;
  • Chief Engineer of ATB of Azalavia Airlines Kerimov E. Sh .;
  • Chief Specialist of the SEC IAC Timoshkin V. Ye.

Also in the investigation was attended by representatives: MAC, ASTC them. A. N. Tupolev, JSC "Perm Motors" , 402 ARZ, CIAM , State Research Institute of Civil Aviation , Ministry of National Security of the Republic of Azerbaijan , Medical Institute of the Republic of Azerbaijan , 13 State Research and Development Institute of Aviation Engineering. The preliminary investigation was carried out by the prosecutor's office of the Babek district of the Nakhichevan Autonomous Republic . Notifications of the incident were sent to the operators of the Tu-134 aircraft in the CIS states and government bodies of the Russian Federation and the Azerbaijan Republic ^[1] .

The preliminary results of the investigation were announced by Nazim Javadov (deputy head of the airline) already on December 26 , that is, 21 days after the disaster. According to them, the disaster occurred as a result of engine failure, which Javadov blamed the Russian Bykovsky Aircraft Repair Plant No. 402, which repaired engines in violation of the standards ^[8] .

Conclusion

The cause of the TU-134B No. 65703 aircraft accident was a forced landing with two autorot engines outside the airfield, which led to the destruction of the aircraft, as a result of a combination of the following factors:

• self-switching off of the left engine after the aircraft’s separation from the runway due to the destruction of the shaft, rotor and stator parts of the turbine as a result of displacement from the fuel nozzle and subsequent burnout of one of the flame tubes;
• an erroneous emergency shutdown by the crew of a serviceable right engine due to an incorrect identification of the failed engine;
• flight mechanics on take-off functions not covered by the RLE - control of the speed and altitude of the flight;
• deficiencies in the ergonomics of the cockpit of the Tu-134B aircraft, which do not fully provide an unmistakable determination of the fact of engine failure, the identification of the failed engine and the implementation of appropriate response actions;
• the need for the crew to maneuver with a roll that exceeds the maximum allowable, in order to avoid a collision with residential buildings located at the rate of emergency landing of the aircraft.

The factor contributing to the failure of the left engine was its operation for more than 30 hours with an unresolved defect.

- ^[1]

In addition, the investigation revealed the following shortcomings ^[1] :

1. Scientific and technical support of the operation of the engine D-30 is carried out in insufficient volume. Technical information on the operation of engines to operators in the CIS countries is not sent.
   The causes of burnout of the combustion chambers of the combustion chambers are not fully investigated, the recommendations to prevent these phenomena are ineffective, as evidenced by the frequency of the defect.
2. In the airline "Azalavia" there is no Tu-134B simulator, the simulators with the flight crew are held in the cockpits of the aircraft. This is allowed by the instructions on FRA , but does not allow to work out the corresponding dynamic stereotype among members of flight crews.
3. The RLE of the Tu-134B aircraft does not contain a change in the technology of the actions of the crew members and the redistribution of duties for the case when the co-pilot controls the aircraft.

Recommendations

1. Conduct additional research to establish the cause of failure of the left engine of the aircraft in the last flight, as well as an analysis of the causes of failures of the D-30 engines that had similar manifestations.
2. Develop and implement recommendations for the further operation of the D-30 III series engines.
3. Develop common rules for the scientific support of engine operation, regardless of the nationality of the developer, manufacturer and operator.
4. To consider the issue of the expediency of changing the layout of the engine control panel on the Tu-134 B aircraft in order to eliminate crew error.
5. Consider adding to the RLE of the Tu-134 aircraft additions aimed at eliminating the crew’s erroneous actions during engine failures during takeoff, as well as adding a section defining the order of crew interaction when piloting the aircraft from the workplace of the 2nd pilot.
   - ^[1]

• Акт по результатам расследования катастрофы самолёта Ту-134Б 65703 Государственного Концерна «Азербайджан Хава Йоллары», происшедшей 05.12.1995 г. в аэропорту Нахичевань Азербайджанской Республики (неопр.) . Межгосударственный авиационный комитет . Дата обращения 10 мая 2013. Архивировано 22 мая 2013 года.