Incident Overview

Date: Saturday 23 December 1972
Aircraft Type: Fokker F-28 Fellowship 1000
Owner/operator: Braathens SAFE
Registration Number: LN-SUY
Location: 16 km W of Oslo-Fornebu Airport (FBU) – ÿ Norway
Phase of Flight: Approach
Status: Destroyed, written off
Casualties: Fatalities: 40 / Occupants: 45
Component Affected: Aircraft Navigation System (specifically, the incorrect instrument approach and the subsequent descent below MSA).Aircraft Navigation System (specifically, the incorrect instrument approach and the subsequent descent below MSA).
Investigating Agency: FlyhavarikommisjonFlyhavarikommisjon
Category: Accident
On December 23, 1972, a Fokker F-28 Fellowship, registration LN-SUY, crashed near Oslo-Fornebu Airport, Norway, resulting in the deaths of four passengers and five survivors. The aircraft, operating under the flight of Braathens, entered a dangerous situation while approaching the runway. The Captain initiated a private communication with the air traffic controller, diverting attention from the ILS procedure. The aircraft subsequently descended below the Minimum Altitude Safety (MSA) and lowered its gear and flaps as per established procedures. It then flew into a dense forest, significantly reducing its visibility and altitude, and ultimately crashed. The probable cause was an incorrect navigation error regarding the runway approach, specifically concerning the ILS procedure and the aircraft’s descent path. The aircraft was attempting to navigate to Oslo-Fornebu Airport while operating below MSA, and the pilot’s actions contributed to the accident.On December 23, 1972, a Fokker F-28 Fellowship, registration LN-SUY, crashed near Oslo-Fornebu Airport, Norway, resulting in the deaths of four passengers and five survivors. The aircraft, operating under the flight of Braathens, entered a dangerous situation while approaching the runway. The Captain initiated a private communication with the air traffic controller, diverting attention from the ILS procedure. The aircraft subsequently descended below the Minimum Altitude Safety (MSA) and lowered its gear and flaps as per established procedures. It then flew into a dense forest, significantly reducing its visibility and altitude, and ultimately crashed. The probable cause was an incorrect navigation error regarding the runway approach, specifically concerning the ILS procedure and the aircraft’s descent path. The aircraft was attempting to navigate to Oslo-Fornebu Airport while operating below MSA, and the pilot’s actions contributed to the accident.

Description

Braathens SAFE flight 239, a Fokker F-28 Fellowship, crashed while on approach to Oslo-Fornebu Airport, Norway, killing 40 occupants; 5 survived the accident. 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 1/2ø 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.

Primary Cause

Incorrect navigation under a truncated instrument approach to runway 06 at Fornebu, leading to a descent below the MSA and subsequent loss of altitude and visibility.Incorrect navigation under a truncated instrument approach to runway 06 at Fornebu, leading to a descent below the MSA and subsequent loss of altitude and visibility.

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