The crash of Tu-134 near Syktyvkar

Tu-134AK with hull number 65120 (serial number 60482, serial number 46-09) was manufactured by the KHAPP plant on June 24, 1978 and was handed over to the USSR MGA , which on July 3 of that year sent it to the 235th Separate Government Squadron. On May 21, 1981, the airliner was transferred to the Syktyvkar squadron of the Komi Civil Aviation Administration . At the time of the crash, the airliner had 17,870 flight hours and 7989 landings ^[1] .

The aircraft operated flight 2306 along the route Vorkuta - Syktyvkar - Moscow . He piloted a crew of 75 flight squad, consisting of a commanderV.F.Dubrovsky , co-pilot D. D. Kuleshov , navigator A. Ya. Dmitrieva and the flight engineer S. I. Shamyrkanova . Cabin crew EE Kazakov and VV Kuchaeva worked in the cabin ^[2] .

At Vorkuta Airport, all luggage was loaded into the rear luggage compartment, while it was not inspected, which was allowed by the instructions. Tu-134 without incident flew from Vorkuta to Syktyvkar. Then another 5 passengers boarded aboard, including two Bulgarian citizens (worked as lumberjacks ). A total of 86 passengers were now on board: 67 adults and 19 children. At 09:55 Moscow time, the airliner took off from Syktyvkar and began to climb ^[2] .

At 10:05, the plane was at an altitude of 5600 meters and about 90 kilometers from Syktyvkar when the “Smoke in the rear trunk” alarm went off. Then, to make sure there was a fire, the commander sent the flight engineer, who soon returned and reported on the presence of fire and smoke in the rear luggage compartment. However, the commander did not believe and did not begin to inform the dispatcher of the fire in violation of instructions, turn on the distress signal and proceed to emergency reduction, but instead, at 10:09:30 he personally went to the tail of the aircraft, taking with him the flight engineer. When he returned back at 10:10:46, the plane had already managed to rise to an altitude of 6,700 meters and was 140 kilometers from Syktyvkar, which, taking into account the delay of about 4 minutes from the time of the fire signal, greatly complicated the further situation. The commander ordered the co-pilot and the flight engineer to eliminate the fire, and he remained in the cockpit with the navigator and began an emergency descent with a left turn towards Syktyvkar. At 10:11:11 he reported to the dispatcher about the fire on board ^[2] .

The aircraft was reduced on average with an instrument speed of about 500 km / h and from a vertical of 19 m / s to a height of 1000 meters at a pressure of 760 mm Hg. Art. while the chassis was removed at an altitude of 5700 meters. The cabin at that time was intensively filled with smoke, because due to the engines running on idle gas (to reduce the increase in speed when lowering), the ventilation intensity fell sharply, and at an altitude of 4000 meters the commander, in violation of the RLE, did not perform depressurization of the aircraft. As for extinguishing the fire, because of the dense smoke and high temperature, the co-pilot and the flight engineer did not penetrate the rear luggage compartment, but simply randomly discharged two of the four fire extinguishers there , which did not reduce the intensity of the smoke. In addition, the co-pilot with the flight engineer did not use oxygen cylinders and smoke masks. Having achieved nothing, they both returned to the cockpit and reported that the fire could not be eliminated ^[2] .

The plane at that time flew at an altitude of 1000 meters in the clouds with a lower limit of 500 meters in the rain. It is likely that due to the low altitude and the great distance from the airport, the crew lost signals from the airport's radio navigation equipment. Then the commander decided on an emergency landing outside the aerodrome, as reported to the controllers, and then re-released the landing gear. Tu-134 descended below the clouds to a height of 300 meters, while its illumination on the radar screens disappeared. Radio communication was also interrupted, and the communication of the dispatchers with the board was carried out already through the aircraft- relay . The cabin, meanwhile, was intensely filled with smoke, which caused passengers to cough, suffocate and bleed from the nasopharynx , and some people lost consciousness. At the same time, the crew did not switch the air conditioning system to the low-gas mode, but taking into account the fact that the engines worked in the low mode, it could not have any effect ^[2] .

For 9 minutes, the crew tried to find a landing site, but due to the low flight altitude with limited visibility (6 kilometers), they did not succeed. Given the heavy smoke, the commander was forced to decide to make an emergency landing directly on the mixed forest located beneath them, not preparing the plane and passengers for emergency evacuation . At 10:27:10, 75 kilometers southwest (azimuth of 228 °) from Syktyvkar, flying at a magnetic heading of 60 ° at an altitude of 23–25 meters above the ground, the Tu-134 collided with tree tops and collapsed rushing through the forest. At the same time, the navigator who violated the RLE immediately died, in part, that he remained at his workplace during an emergency landing. After 195 meters from the site of the first strike, the airliner touched the ground, and after 25 meters both wing consoles were torn off. Racing along the ground 145 meters (340 meters from the site of the first strike), the fuselage of the plane, destroyed in three parts, stopped. The fuel leaked from the damaged fuel tanks flared up and a ground fire arose, partially destroying the aircraft ^[2] .

Passengers were evacuated independently through the front door of the front luggage compartment, the cockpit window and the fuselage breaks, while cabin crew helped pilots and the flight mechanic escape. In the rain, someone managed to light a fire to enable people to warm themselves. At 13:35 the crash site was found by a rescue helicopter, and at about 19 hours the survivors were evacuated. In total, 45 adult passengers, 7 children, a navigator and a flight engineer (died from wounds) died in the crash, and according to the results of a forensic medical examination, some passengers died from poisoning by burning products. The remaining 38 survivors (22 adult passengers, 12 children, pilots and cabin crew) received various injuries ^[2] .

The resulting land fire almost completely destroyed the plane, which virtually eliminated the possibility of studying the wreckage. Overall IAC Commission Investigation ^{[ specify ]} lasted 5 months, while fifty additional studies were conducted in various research institutes and organizations. So, even for ground tests at the airport of Yerevan , the Tu-134A was burnt aboard 65657 (decommissioned after the accident in the Abkhaz ASSR on July 10, 1984 ) ^[3] . During the investigation, the chairman of the commission was also replaced. In total, the investigation materials took 4 volumes of 6-8 cm thick. On December 4, 1986, the act was signed with the dissenting opinion of MAP representatives ^[2] .

Conclusion : The emergency situation on the plane arose in the set of the train at an altitude of 5600 m due to a fire in the rear luggage compartment, which spread in its floor and underground space at the time when the crew could begin to extinguish it. The fire was not eliminated by the measures taken, which, due to intense smoke in the passenger compartment, led to the necessity of making an emergency landing outside the aerodrome, the decision on which was made by the crew at the end of the emergency descent, 9-11 minutes after the “Smoke in the rear trunk” alarm was triggered. 20 minutes after the alarm went off, due to the inability to pick up a site in a wooded area, the crew made an emergency landing on the forest, which led to the destruction of the aircraft and a ground fire.

It is not possible to unequivocally establish the cause of a fire in flight due to the impact on the aircraft structure of an intense and prolonged fire on the ground.

Possible causes of a fire could be the ignition of a vehicle prohibited from transportation of a self-igniting substance or liquid in the baggage of passengers, followed by the penetration of a burning liquid into the underfloor space or the ignition of electrical wires soaked with combustible liquid in the underground part Zwo . In the event of an emergency occurrence and development, the crew allowed deviations from the RLE requirements regarding the disabling of the distress signal, the repeated, unregulated verification of the fire focus by the aircraft commander after the report of the flight mechanic, non-use of masks, oxygen cylinders and two remaining portable fire extinguishers. In addition, the crew, in violation of the RLE, the air conditioning system was not switched to maximum ventilation during an emergency reduction. A thorough analysis of the crew’s actions showed that these deviations did not significantly affect the outcome of the flight, given that clandestine compartments of the baggage compartments of GA aircraft are not considered fire hazardous and are not equipped with a stationary fire extinguishing system.

In the dissenting opinion, the MAP representatives exclude the possibility of leakage of AMG-10 hydraulic fluid or damage to the wiring in the underground space of the WB and a fire there. According to their conclusion, baggage could be ignited as a result of self-ignition or ignition from a foreign object after an unauthorized person or passenger entered the security zone while standing in Syktyvkar airport.

- ^[2]

Alternate

Among the 5 additional passengers who landed in Syktyvkar were 2 residents of Bulgaria (probably Yetov Jordan Hristov (died) and Neychev Boyko Kirov (wounded)) who worked as loggers in Komi. They carried the Ural chainsaw with them in their hand luggage. Although there is no evidence that the door from the passenger compartment to the rear luggage compartment opened during parking, it is impossible to exclude this version, since it is located near the toilet, and the cabin crew at that time were in front of the kitchen area. In addition, when examining the scene of the accident, the details of this chainsaw, including the tank with the remaining fuel, were found in the rear luggage compartment, that is, it could be transferred there from the passenger compartment ^[2] .

• The crash of Tu-134 near Pervouralsk