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Accident
Last updated: 10 December 2016
Status:Schlussbericht
Datum:Samstag 23 Dezember 1972
Zeit:16:34
Flugzeugtyp:Silhouette image of generic F28 model; specific model in this crash may look slightly different
Fokker F-28 Fellowship 1000
Fluggesellschaft:Braathens SAFE
Kennzeichen: LN-SUY
Werknummer: 11011
Baujahr: 1969-04-14 (3 years 8 months)
Betriebsstunden:8228
Anzahl Zyklen der Zelle:16710
Triebwerk: 2 Rolls-Royce Spey 555-15
Besatzung:Todesopfer: 3 / Insassen: 3
Fluggäste:Todesopfer: 37 / Insassen: 42
Gesamt:Todesopfer: 40 / Insassen: 45
Sachschaden: Zerstört
Konsequenzen: Written off (damaged beyond repair)
Unfallort:16 km (10 Meilen) W of Oslo-Fornebu Airport (FBU) (   Norwegen)
Flugphase: Annäherung (APR)
Betriebsart:Inländischer planmäßiger Passagierflug
Flug von:Ålesund-Vigra Airport (AES/ENAL), Norwegen
Flug nach:Oslo-Fornebu Airport (FBU/ENFB), Norwegen
Flugnummer:BU239
Unfallbericht:
Braathens flight 239 turned some 10 NM ahead of the ILS-procedure for runway 06 at Oslo-Fornebu Airport while the captain was having private communications regarding Christmas with the ACC-controller. The F-28 also descended below MSA and the crew lowered the gear and flaps as it was established on the ILS. It then flew into the woods more than 4 NM off course in darkness and fog.

Accident cause (translated from Norwegian):

The probable cause of the aircraft LN-SUY that crashed near Asdoltjern in Asker on 23 December 1972 at 1634:55 was incorrect navigation under a truncated instrument approach to runway 06 at Fornebu.
The fact, which could not to specifed more closely, however, must have been committed when the aircraft left 3500 feet but was not fatal for the last 13 seconds when it was flown 1510 feet below the glide path down while aboard it must have been clear that neither was at or within 2 1/2° from the ILS facility centerline.

Contributing factors:
a) The aircraft's ADF no. 2 was probably tuned to 100 kHz erroneously.
b) Fornebu ILS to runway 06 provides useable glideslope signals from Sylling to the accident site.
c) Outer Marker on Steilene can provide convincing signals for passage of an outer Marker Beacon in apparently correct glidepath altitude between Sylling and the accident site in the F-28 aircraft if "merkefyrbryteren" are put in setting HIGH.

Unfortunate circumstances:
a) The commander was not as rested as he could have been according to regulations
b) The commander made radio calls with air traffic controller in the control tower that were not allowed during the initial phase of the approach.
c) Control tower bearing indicator was moved from its fixed position in the control desk, so that the possibility of random directional control was reduced.
d) Training Position for approach control at Oslo ATCC was unmanned.

Informationsquelle:
» Willem Wendt

Official accident investigation report
cover
investigating agency: Flyhavarikommisjon - Norway
report status: Final
report number: Final Report
report released:17 December 1975
duration of investigation: 2 years and 12 months
download report: Final Report

Fotos

photo of Fokker F-28 Fellowship 1000 LN-SUY
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Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Ålesund-Vigra Airport to Oslo-Fornebu Airport as the crow flies is 379 km (237 miles).

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