Accident Tu-154 over Domodedovo

Tu-154B-2 with registration number CCCP-85327 (serial number 79A-327, serial number 0327) was launched by the Kuibyshev Aviation Plant on February 24, 1979 . The liner was transferred to the Ministry of Civil Aviation , which by April 14 sent it to the Abakan Joint Aviation Unit of the Krasnoyarsk Civil Aviation Administration. The aircraft was equipped with three NK-8-2U turbofan engines with a thrust of up to 10.5 tf each. During operation, board 85327 underwent only one repair - on November 25, 1982 at the Vnukovo Aircraft Repair Plant ( No. 400 ) , after which it had an operating time of 5381 hours 40 minutes and 2020 take-off and landing cycles. The total operating time of the airliner from the beginning of operation was 11,922 hours 2 minutes and 4687 take-off-landing cycles ^{[1] [2]} .

• The aircraft commander is Nikolai Petrovich Laptev. Born in 1945 , pilot of the 1st class, was qualified for flights on the Yak-12 , An-2 , An-24 and Tu-154 . The total flight time is 13,656 hours, of which 3,305 hours on the Tu-154, including 2247 as commander ^[1] .
• The co - pilot is Poptsev Alexander Nikolaevich. Born in 1949 , pilot of the 1st class, was qualified for flights on the An-2 , An-24 and Tu-154 . The total flight time is 10 762 hours, including 938 hours on the Tu-154 ^[1] .
• Navigator - Pimenov Mikhail Petrovich. Born in 1953 , navigator of the 2nd class, was qualified for flights on the Il-14 , An-24 , An-26 and Tu-154 . The total flight time is 6801 hours, of which 4052 hours are in the position of Tu-154 navigator ^[1] .
• Flight Engineer - Akhpashev Emelyan Gavrilovich. Born in 1952, a 3rd-class flight engineer, was qualified for flying on the Tu-154 . The total flight time of 2100 hours, all on the Tu-154 ^[1] .

Cabin crew worked in the cabin, the number of which is not available.

The plane performed a passenger flight from Chelyabinsk to Moscow ( Domodedovo ). On board were 175 passengers (164 adults and 11 children). At the time of the events, the Moscow region was surrounded by a low pressure area, and on the line from Sheremetyevo to Vnukovo, a blurred front of occlusion was moving south and south-west. To the east of this front was a variable (4-6 points) thick cumulus and cumulonimbus clouds with a lower boundary of 1000-1500 meters and an upper 3-5 kilometers. In the cloud layer from 2500 to 4000 meters, severe icing was observed, and in the cumulonimbus clouds there was also strong turbulence and electrification . At the same time, Moscow air traffic controllers warned the crew in advance that thunderstorm flares were observed in the area of ​​the Marino air traffic control system (north of Domodedovo Airport and near Elektrougli ), which are recommended to be bypassed from the south ^{[1] [3]} .

Onboard 85327, dropping to a height of 3600 meters, bypassed one of the thunderstorm foci when it fell into the zone of heavy rain, while icing was also observed. Piloting at this stage was performed by the second pilot Poptsev, who suddenly saw how the airspeed began to decline and soon dropped to zero. Pilots lowered the nose of the aircraft, but this did not help, as did putting the engines in take-off mode. The flight took place in the clouds, that is, without visible external landmarks. Then at 15:21 at an altitude of 1800 meters the car left the clouds, which allowed the crew to navigate and understand that they were rushing to the ground at great speed. Then the commander pulled the helm toward himself, forcing the plane to lift his nose out of the dive, while experiencing severe overload. It was subsequently established that the Tu-154 was reduced with a vertical speed of 100 m / s and an instrument speed of about 813 km / h, and during the maneuver to exit the dive, the machine experienced an overload of 3.2 units, i.e. significantly higher than calculated, but not collapsed. Further, the crew completed a normal approach and landed safely at Domodedovo Airport. None of the crew or passengers on board were injured ^[3] .

The crew tried to hide the fact of the incident, but this was revealed when preparing the aircraft for the return flight. The check revealed that the airliner has a permanent deformation, as a result of which corrugations appeared on the skin. In this regard, the board 85327 was found unsuitable for further operation, but it was not written off, but instead transferred to the Office of educational institutions and deposited at Sheremetyevo airport ^[2] .

As it was found, when departing from Chelyabinsk, the crew forgot to turn on the heating of the full pressure receivers . When the plane began to decline in the clouds and entered the icing zone, the RPMs began to become covered with an ice crust, which gradually clogged the inlet openings, which led to a drop in the instrument speed reading ^[3] .

Commission findings ^[3]

1. The flight mass and alignment of the aircraft did not go beyond the established limits.
2. According to the flight documentation, the level of crew training meets the requirements of the Ministry of Civil Aviation that regulate flight operations. The crew was not prepared for this flight, as it did not comply with the requirements of the Flight Operations Manual , as a result of which it allowed incorrect piloting operations under conditions of a short-term distortion of the instrument speed indicators.
3. The crew did not fulfill the following requirements:
   • Before take-off, the navigator Pimenov M.P. did not turn on the heating of the RPM, and the co-pilot A. N. Poptsev did not control their inclusion;
   • when getting into the icing zone and decreasing speed indicators while lowering the aircraft, the crew did not check the inclusion and serviceability of the heating of the RPM (FAC, co-pilot);
   • failed to comply with the recommendations of the Flight Operation Manual regarding the preservation of the established mode of operation of the engines and the control of maintaining the specified mode of flight for other instruments ( horizon , variometer , Doppler ground speed meter ).
4. The co-pilot, piloting the plane, the crew did not inform about their actions and changes in the instrument speed. FAC Laptev incorrectly assessed the position of the aircraft in space and turned it into a steep decline with the issuance of take-off operation of the engines; when removed from the reduction, it created an unbalanced overload of 3.2.
5. Radio engineering controls and flight support were operational and made it possible to carry out safe air traffic control in the Moscow air zone.
6. Meteorological support for flights was in accordance with the NSO GA-82. In the area of ​​Mariino OPS, in the layer of clouds from an altitude of 2500 meters to 4000 meters, intense icing, turbulence and electrification of the atmosphere took place.
7. The glider and its systems, power plants, aircraft and electronic equipment of the aircraft were operational. A short-term decrease in the instrument speed values ​​according to the standard indicators was a consequence of the clogging of all three receivers of full pressure under icing conditions due to the non-inclusion of their heating by the crew.
8. Maintenance of the aircraft as a whole was carried out in accordance with the operational documentation. However, in MSRP-64, malfunctions of the MU-615A elevator and RA-56 sensors were not detected.
9. Due to the significant excess of the maximum allowable values ​​of the flight speed and vertical overload, the main power elements of the airframe received permanent deformation.
10. Aircraft Tu-154B-2 No. 85327, serial number 79A327 for further operation is not suitable and must be decommissioned in the prescribed manner.

The commission called the cause of the accident violations in the actions of the crew, which did not turn on the PPD heating, which caused it to pilot when the instrument speed indicators were incorrectly displayed and brought the aircraft to flight modes that exceeded the calculated ones ^{[1] [3]} .

The incident is mentioned in the memoirs of the pilot instructor Tu-154 Vasily Ershov ^[4] :

So the crew took off and stomped on Moscow. What happened to them there before take-off - about the same as what we have today - but they forgot to turn on the PDP , and in flight no one paid attention. The air is dry at altitude, even in winter, even in summer, there are no conditions for icing , but at a decrease, as they entered the clouds, it was already not at a very high altitude, there were just conditions for icing. They also included an anti-icing system : a wing, tail unit, engine air intakes ... and no one looked at the RPM heating toggle switches for the entire flight. They are located above the co-pilot , the navigator is supposed to turn them on, and the co-pilot answers according to the control card: “The RPM heating is on, ready for take-off”. Also the Tupolev absurdity in crew work technology. But then, at the beginning of the operation of the aircraft, they somehow did not pay much attention to it, especially since the Tupol pierced the clouds in a matter of seconds and practically did not ice at all. So they were dropping in the clouds, reporting on the occupied echelons , lingering on them to the team and dropping again. And no one noticed that the speed began to quietly go to zero. The co-pilot piloted on the instructions of the navigator, and the captain was distracted by the locator to make sure there were thunderstorms ahead. The second pilot thought that the speed was low, and he gave the helm away from himself. No, not enough - he gave more. The speed did not grow! He thrust the helm almost all the way forward. Speed ​​went to zero! Naturally, it went to zero: the hole froze, and less and less pressure head fell into the gauge box of the device. And when the flow could not get into the tube at all, the device naturally showed zero speed. The captain thought something was wrong. The sixth sense made me tear myself away from the locator and cast a familiar glance at the instruments. He didn’t immediately get it: speed? ... speed? ... the variometer shows the climb ... the horizon ... why is the color of the ball brown? Altitude ... Altitude - the arrows rotate too fast ... And then the plane fell out of the clouds, almost in a sheer dive . And all the readings of the instruments took their places in the captain’s erupted brain: the variometer “twisted” the decline so that it began to show climb, the horizon confirmed this decrease - and here it is, mother earth! Seeing the land rushing towards him, the captain grabbed the helm ... 1800 meters high was enough to withdraw from the dive. And sat safely. But in the parking lot, when the refueling hoses were connected, fuel began to flow from the wings of the fountain. Upon closer inspection, it turned out that deformation corrugations went all over the plane: the car almost collapsed in the air. Then the decryption showed that all the limits of permissible speeds and overloads were significantly exceeded; saved by a miracle. The plane was decommissioned; the captain took the lesson and flies so far, having gained enormous experience over twenty-odd years after that incident; Now he is a respected man, a master. The Lord keeps him.

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