Aero Flight 311
| Summary | |
|---|---|
| Date | January 3 1961 |
| Cause | Pilot error, stall |
| Site | Koivulahti, Finland |
| Origin | Kruunupyy Airport |
| Destination | Vaasa Airport |
| Passengers | 22 |
| Crew | 3 |
| Fatalities | 25 |
| Survivors | 0 |
| Aircraft | |
| Aircraft type | Douglas DC-3C |
| Operator | Aero O/Y |
| Tail number | OH-LCC |
Aero Flight 311 (AY311), often referred to as the Koivulahti air disaster, was a scheduled domestic passenger flight operated by Aero O/Y (now Finnair) between Kruunupyy, Finland and Vaasa. The aircraft, a Douglas DC-3C, crashed near Koivulahti on January 3, 1961, killing all twenty-five people on board. The disaster remains the worst aviation accident in the history of Finland.
Flight chronology
The Douglas DC-3, registered OH-LCC, was scheduled to take-off at 7:00, but take-off preparations were late and the plane departed at 7:16. The co-pilot requested free flying altitude from the air traffic control, which was permitted. This allowed Flight 311 to fly at any altitude above the minimum flight altitude for the Kruununkylä-Vaasa route which was 1500 feet (450 meters). The pilots did not follow these regulations for the last 40 kilometers, during which they flew below 100 meters. [1]
Shortly after the flight's last radio contact with the air traffic control, in which the pilots confirmed the weather report and said that they would be at Seppä lighthouse in a few minutes, the flight was starting to prepare for landing by descending to below 50 meters. Next, the plane turned abruptly to the left. This slowed the plane and distrupted air flow significantly. The pilots tried to correct the situation by applying full throttle. This did not help and the plane went into a spin. The last thing seen by eye-witnesses on ground was that the pilots had turned landing lights on before the plane crashed into woods at 07:40:30 at a 70-degree angle. [2]
The first people arrived to the scene after 10 minutes could not attempt to rescue anyone from the wreck as it was burning in 15 meter long flames. The aircraft was completely destroyed by impact forces and the fire. [3]
Investigation
The officials concluded that the plane was completely capable of flying, and that the probable cause for the accident was a pilot error when turning to the left, although it was possible that one passenger was interrupting the pilots based on his body's location.
The possibilities of the plane hitting a tree top or exploding in midair were also investigated, but it was concluded to be inaccurate as no evidence suggesting either of these was found on the scene, and eye-witnesses had not seen an explosion or the aircraft striking tree tops. It was also possible that the plane controls were frozen, as it was a cold winter day. The investigation report concluded that this was not possible in the flying conditions, and an intact wing that had separated from the main wreckage did not have any ice on it. The pilots did not report any icing on the plane via radio either. [3]
According the report by the Accident Investigation Board, the pilots, Captain Lars Hattinen, a World War II fighter ace of 6.5 victories, and co-pilot Halme, were not in a fit state to fly. They had not slept at all on the previous day, and they had been drinking. In an autopsy, pilot Hattinen had a blood alcohol level of 2 ‰, whilst co-pilot Halme had a blood alcohol level of 1.56 ‰.[4] Co-pilot Halme was nevertheless not considered to be responsible for the accident as he was in Hattinen's command, and had no responsibility to prevent him from flying.[5] It is however against the International Civil Aviation Organization's treaty and the pilots' personal job contracts to be drunken in the plane, which the pilots ignored.
Flight number
Although airlines often retire the flight numbers of flights involved in fatal accidents, the successor of Aero O/Y, Finnair, continues to use flight number AY311 on its Helsinki-Vaasa route as of 2007. The flights are operated with Airbus A319. [6]
Notes
- ^ Accident Investigation Board of Finland Report, p. 17
- ^ Accident Investigation Board Finland Report, p. 18
- ^ a b Accident Investigation Board Finland Report, p. 19
- ^ Accident Investigation Board Finland Report, p. 15
- ^ Accident Investigation Board Finland Report, p. 14
- ^ Finnair - Timetables for domestic flights Retrieved 7.6.2007
References
External links
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