Aeroflot flight 5484
| Aeroflot flight 5484 | |
|---|---|
.jpg) Aeroflot aircraft of the same construction |
|
| Accident summary | |
| Accident type | Loss of control |
| place | Near Kirsanov |
| date | 29th August 1979 |
| Fatalities | 63 |
| Survivors | 0 |
| Aircraft | |
| Aircraft type | Tupolev Tu-124W |
| operator | Aeroflot |
| Mark | CCCP-45038 |
| Departure airport | Odessa airport |
| Stopover | Kiev Boryspil Airport |
| Destination airport | Kazan airport |
| Passengers | 58 |
| crew | 5 |
| Lists of aviation accidents | |
On August 29, 1979, an Aeroflot Tupolev Tu-124 crashed on the second part of the inner-Soviet scheduled flight Aeroflot flight 5484 from Odessa via Kiev to Kazan , killing all 63 occupants. It is the worst accident involving a Tu-124.
Plane and crew
The plane was a 16-year-old Tupolev Tu-124W with the air vehicle registration CCCP-45038, with two turbofan engines of the type Solowjow D-20 was equipped P. It was used from December 2, 1963 and was involved in a fatal incident on July 27, 1966 on Aeroflot flight 67 and was then repaired.
The crew consisted of a flight captain , a first officer , a flight engineer , a navigator and a flight attendant .
course
The Tu-124 took off from Kiev on August 28 at 11:21 p.m. Moscow time and climbed to a cruising altitude of 9,000 m on a course of 65 ° (northeast) at a speed of 525 to 530 km / h IAS (not to be confused with the actual airspeed). At 12:23 a.m., the pilots made radio contact with air traffic control in Penza and reported the entry into the airspace there. There was no further radio contact. At 7:40 a.m., the debris was found in a swampy , wooded floodplain of the Worona .
examination
The debris field extended over a length of 10,750 m and a width of 1,650 m, which meant an area of about 17.75 km². The debris showed signs of a vertical drop at low horizontal speed, suggesting the Tu-124 would break apart at high altitude. It was found that the landing flaps had previously been extended by 30 °.
The flap levers of both pilots were in an operational condition. However, the left one was not locked in the neutral position and it was not possible to determine whether it was in the extended or retracted position at the time of the breakup. The control relays in the junction box and in the electromechanical drive of the landing flaps were also operational. On the other hand, due to the damage, it could not be determined whether the deployment protection system for landing flaps 1 and 2 was working. The junction boxes for the electrical landing flap control system and parts of the wiring could not be found because of the widespread distribution of the debris.
The investigators reconstructed the accident:
At 0:24:35 a.m., while cruising at 9,000 m, the landing flaps began to extend, whereupon the pilots noticed this and 8 s later deactivated the pitch channel of the autopilot . They initially held the control horns in the neutral position for 2 s and then pulled them back 2 ° for a further 6 s, but this did not counteract the descent. Then the pilots released the control horns 17 seconds after the incident began, causing the aircraft to dive into a steep dive . First, the overspeed warning was triggered at a speed of 590 km / h IAS. Then the right inner and then the outer flaps on both sides broke off at an altitude of 6,000 m and a speed of 660 km / h IAS, causing the Tu-124 to roll to the right at an additional 45 ° / s . Finally, at 12:26 a.m. at an altitude of 3,000 m at a speed of 860 km / h IAS, a rate of descent of 280 m / s and a load of 5 g , part of the left wing broke off and then the whole aircraft broke into many Parts.
root cause
Due to missing or ambiguous pieces of evidence, it could not be determined why the landing flaps were deployed. The most likely scenarios are:
- a) The flap lever was accidentally thrown. The construction would not prevent an extension while cruising, which was found, among other things, in the test on 16 Tu-124s
- b) An electrical fault that was not found during maintenance and normal operation and that sent an incorrect signal to the landing flap system. However, the examination of the electrical systems of 6 Tu-124s did not substantiate the suspicion.
Scenarios that would explain why the pilots let go of the control horns are:
- a) The pilots were busy with other tasks, e.g. B. retract the flaps
- b) The pilots were misled by the variometer , which had indicated a climb of 15–20 m / s instead of a descent of 40–45 m / s
- c) The dive exerted (too) great forces on the control horns
- d) The pilots were impaired by the forces acting in the dive
- e) A combination of these factors.
consequences
After the accident, the Tu-124 was no longer used in regular passenger traffic.
Similar cases
On December 17, 1961, an Ilyushin Il-18 crashed on Aeroflot flight 245 under similar circumstances.
swell
- Aircraft accident data and report CCCP-45038 (1966) in the Aviation Safety Network (English)
- Aircraft accident data and report CCCP-45038 (1979) in the Aviation Safety Network (English)
- Accident report on airdisaster.ru
- Information about the accident on avia.pro
Coordinates: 52 ° 18 ′ 36 ″ N , 42 ° 21 ′ 36 ″ E