Braathens SAFE Flight 239

Braathen SAFE Flight 239, also known as the Asker Accident (Asker-ulykken), was a controlled flight into terrain of a Fokker F28 Fellowship into Vestmarka in Asker, Norway, on 23 December 1972 at 16:33. The Braathens SAFE aircraft was en route on a scheduled flight from Ålesund Airport, Vigra and crashed during approach to Oslo Airport, Fornebu. Forty of the forty-five people on board the aircraft died, making it the deadliest civil aviation accident in Norway until Vnukovo Airlines Flight 2801 in 1996. According to Norwegian newspaper Dagbladet on 23 December 1992, a Danish citizen died of late complications in 1976.

The pilots took a short-cut during approach on runway 06 at Fornebu. Combined with false signals from the instrument landing system (ILS), this caused the pilots to misunderstand their location. This in turn led them to take an incorrect landing path, causing the plane to hit ground in a hilly area. The rescue operation was initiated almost immediately, but it took six and a half hours to find the aircraft. Three years later, the investigation commission concluded that various measures should be put in place to improve navigation, to avoid similar situations in which pilots could experience any confusion or misunderstanding about their location.

Flight

The accident aircraft, a Fokker F28 Fellowship 1000 had aircraft registration LN-SUY and was named Sverre Sigurdsson. It was equipped with two Rolls-Royce Spey Jr. 555-15 engines. Braathens SAFE was the launch customer of the F28 and Sverre Sigurdsson was the first F28 to fly in revenue service, in early 1969. By 1972 Braathens had six such aircraft in its fleet. The airline had seen some operational difficulties as an early operator of the aircraft type. LN-SUY had serial number 11011 and had at the time of the accident flown 8,228 hours and had conducted 16,710 cycles. It had a capacity of sixty-five passengers, and was insured with Norsk Flyforsikringspool.

Flight 239 was a scheduled service from Ålesund Airport, Vigra to Oslo Airport, Fornebu, estimated to take 45 minutes. It was marginally delayed when it departed Vigra at 16:00 with a crew of three and forty-two passengers, including four babies. As the flight was the day before Christmas Eve, it was largely used by people traveling home or to visit family for Christmas and people heading abroad for Christmas holiday. The captain had been employed by Braathens for sixteen years, the last ten as captain. There was one member of cabin crew. As it was a short domestic flight, only soda pop and beer were served, not coffee.

Crash

The norm for landing at Fornebu was to rendezvous with a way point, RUMBA, and conduct a fifteen-degree left turn for about half a minute. The aircraft would then be aligned with runway 06 and could glide down following the instrument landing system (ILS). This maneuver would nominally take place at an altitude of 1,100 meters (3,500 ft). However, in clear weather the pilots often opted for a short-cut to reach the approach path more quickly. Because of the topography, it was possible that the ILS beams would deviate up to twenty-five degrees, which could cause the pilots to turn the aircraft too early and would cause the aircraft to fly over a range of hills on the wrong heading. This was a known fault with the system and pilots would therefore check the direction of the radio beacon at Asker to ensure they were in the correct position. This short-cut was carried out by Flight 239.

The pilots therefore had full control of the aircraft, but were not aware of their location at the time of the impact. They carried out their turn about 10 NM too early. At this time the captain was having a private conversation concerning Christmas celebrations with the air traffic controller. The aircraft descended below the lowest safe altitude and lowered its gear and flaps as if they were on the nominal bearing. Sverre Sigurdsson was flying a course too far east and was possibly flying through strong winds. The impact took place at 16:33 close to the lake of Asdøltjern in Vestmarka. The aircraft was 4 NM off course in darkness and fog.