Scandinavian Airlines system flight 751
| Scandinavian Airlines system flight 751 | |
|---|---|
_OY-KHO_KvW-1.jpg) The unlucky machine on June 1, 1991 |
|
| Accident summary | |
| Type of accident | Engine failure due to clear ice |
| location | Near Stockholm , Sweden
|
| date | December 27, 1991 |
| Fatalities | 0 |
| Survivors | 129 |
| Injured | 87 |
| Aircraft | |
| Aircraft type | McDonnell Douglas MD-81 |
| operator | SAS Scandinavian Airlines |
| Mark | OY-KHO |
| Departure airport | Stockholm / Arlanda Airport |
| Stopover | Copenhagen Kastrup Airport |
| Destination airport | Warsaw Okęcie Airport |
| Passengers | 123 |
| crew | 6th |
| Lists of aviation accidents | |
Scandinavian Airlines System Flight 751 was a flight of SAS Scandinavian Airlines , which was to be operated on December 27, 1991 with a McDonnell Douglas MD-81 from Stockholm / Arlanda Airport to Copenhagen-Kastrup Airport .
Flight history
The McDonnell Douglas MD-81 took off from runway 08 at Stockholm / Arlanda airport at 08:47 with the intermediate destination Copenhagen-Kastrup. The aircraft was de-iced prior to takeoff because there was snow on the wing tops and ice formation was discovered on the wing undersides. 25 seconds after take-off, the right engine was in the condition of the compressor pumping , a disturbance in the internal aerodynamics that can lead to a loss of power and the destruction of the engine. After 65 seconds of flight, this condition also occurred in the left engine. Shortly thereafter, both engines failed. Since the flight altitude was not sufficient for a return to the airport, an emergency landing was carried out on a field after a glide flight in a northerly direction, during which the aircraft fuselage broke into three parts. Despite the severe damage, all inmates survived the accident. The accident is therefore also referred to as the Gottröra miracle (Miraklet i Gottröra) after the town of Gottröra, near which the landing took place . The flight lasted 4 minutes 7 seconds and reached a height of approx. 1000 m above ground.
Airplane and crew
The two turbofan engines of the type Pratt & Whitney JT8D 217C equipped aircraft with the aircraft indicator OY-KHO was from McDonnell Douglas prepared and SAS Scandinavian Airlines System operated. It was commissioned in 1991 and had a total of 1,608 operating hours.
The 44-year-old flight captain Stefan Rasmussen had completed a total of 8,020 flight hours , 590 of them on this type of aircraft; The 34-year-old co-pilot Ulf Cedermark had a cumulative flight experience of 3,015 flight hours, 76 of which were on this type of aircraft. In addition, three flight attendants and the flight captain Per Holmberg, who was traveling as a passenger, went to the cockpit immediately after the engine problems began to assist the crew.
Causes of accidents
The accident machine had arrived from Zurich the previous evening. The temperature at cruising altitude was about −60 ° C. With 2550 kg of fuel in each of the two wing tanks, the aircraft had a relatively large amount of residual fuel on board, which on the morning of the day of the accident still had a temperature of well below 0 ° C, which had led to the formation of ice on the wings during the night due to the sleet that had fallen . During de-icing, only snow was removed from the wings; the layer of clear ice that had formed at night and would have required a different de-icing procedure was not discovered. During the take-off rotation , the clear ice loosened due to the bending of the wings into pieces of different sizes, some of which were sucked in by the two engines at the stern and there damaged the turbine blades of the fan stage and several compressor stages. This damage caused the compressors to pump. The flight captain tried to bring them back into a stable operating state by reducing the engine power. However, the pilots were not aware that the aircraft was equipped with Automatic Thrust Restoration (ATR), a system for automatically increasing thrust , which, with increasing flight altitude, was also intended to compensate for the power loss of one engine by increasing the power of the other engine, which worsened the situation here . This system was not part of the training of the pilots and the existence of Scandinavian Airlines was unknown as it had not been ordered. There was also no way to turn this system off to completely manually control engine performance. According to the final accident report, it would most likely have been possible to return to Stockholm / Arlanda Airport with reduced engine power and land there. In addition to pumping both engines, the crew received a fire indication from the left engine. The co-pilot then activated the extinguishing system, which would have made a restart of this engine impossible in any case.
Similar cases
Aeroflot flight 7841 on February 1, 1985: In the similarly built Tupolev Tu-134 , both engines failed due to clear ice for a similar cause, whereupon the pilots made an emergency landing.
literature
Official final report of the Swedish Accident Investigation Commission
filming
- Series Mayday - Alarm in the Cockpit , Season 10, Episode 3 .
Individual evidence
Coordinates: 59 ° 46 ′ 0 ″ N , 18 ° 8 ′ 0 ″ E