Aero Flight 311

Infobox Airliner accident|name=Aero Flight 311
Crash

Date=January 3 1961
Type=Pilot error, stall
Site=Koivulahti, Finland
Fatalities=25
Survivors=0
Aircraft Type=Douglas DC-3C
Origin=Kronoby Airport
Destination=Vaasa Airport
Operator=Aero O/Y
Tail Number=airreg|OH|LCC|disaster
Passengers=22
Crew=3

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 Kronoby, 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 deadliest 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. [Accident Investigation Board of Finland Report, p. 17]

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 disrupted 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 the landing lights on before the plane crashed into the woods at 07:40:30 at a 70-degree angle. [Accident Investigation Board Finland Report, p. 18]

The first people to arrive at 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. Accident Investigation Board Finland Report, p. 19]

Investigation

The officials concluded that the plane had been completely airworthy, and that the probable cause of the accident was a pilot error when turning to the left. The possibility was noted that one passenger had been interrupting the pilots based on his body's location.

No evidence was found of any technical malfunction, of the plane hitting trees, nor of an explosion. It was possible that the plane controls had been frozen, as it was a cold winter day. The investigation report concluded that this was unlikely in the flying conditions, and an intact wing that had separated from the main wreckage did not have any ice on it. The pilots had not reported any icing on the plane via radio either.

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, had not been in a fit state to fly. They had not slept at all on the previous day, and they had been drinking heavily: in an autopsy, pilot Hattinen had a blood alcohol level of 2 ‰, whilst co-pilot Halme had a blood alcohol level of 1.56 ‰. [Accident Investigation Board Finland Report, p. 15] Hattinen had thus neglected his responsibility for the plane's and passengers' safety, and while co-pilot Halme had been in Hattinen's command, with no responsibility to prevent him from flying, he too should not have been flying that day. [Accident Investigation Board Finland Report, p. 14] It is against the International Civil Aviation Organization's treaty as well as the pilots' personal job contracts to be drunk in the plane, which the pilots had 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. [ [http://www.finnair.com/filecontent/com/aytimetables/finland.pdf Finnair - Timetables for domestic flights] Retrieved 7.6.2007]

Notes

References

* [http://www.onnettomuustutkinta.fi/uploads/x2z9gsyz7kf45.pdf Official report by the Accident Investigation Board Finland] fi icon

External links

* [http://www.airdisaster.com/cgi-bin/view_details.cgi?date=01031961&reg=OH-LCC&airline=Finnair AirDisaster.com account of the crash]
* [http://aviation-safety.net/database/record.php?id=19610103-0&lang=en Aviation Safety Network Accident description]