Incident Overview

Date: Tuesday 30 January 1973
Aircraft Type: McDonnell Douglas DC-9-21
Owner/operator: Scandinavian Airlines System – SAS
Registration Number: LN-RLM
Location: Oslo-Fornebu Airport (FBU) – ÿ Norway
Phase of Flight: Take off
Status: Destroyed, written off
Casualties: Fatalities: 0 / Occupants: 33
Component Affected: DC-9 aircraft ? specifically the pitot tube system.DC-9 aircraft ? specifically the pitot tube system.
Category: Accident
A DC-9, ‘Reidar Viking’, experienced a catastrophic failure during takeoff from Oslo to Alta due to a false stall warning system activation. The aircraft rapidly overran the runway and collided with ice on the Oslofjord, resulting in a sinking event.A DC-9, ‘Reidar Viking’, experienced a catastrophic failure during takeoff from Oslo to Alta due to a false stall warning system activation. The aircraft rapidly overran the runway and collided with ice on the Oslofjord, resulting in a sinking event.

Description

The DC-9, named “Reidar Viking”, was operating on flight 370, departing Oslo for a flight to Alta with an intermediate stop at Troms?. At 23:18 the crew was cleared for takeoff from runway 24. The takeoff run was normal and the DC-9 rotated at VR (125kts). At that moment the stall warning system activated. Although the speed had increased to 140 knots, the pilot decided to abort the takeoff. The remaining 1100 m however was not enough to bring the aircraft to a halt. The reversers did not deploy completely and the aircraft overran the runway and onto the ice covered Oslofjord. The DC-9 came to rest 20 m from the bank of the fjord. All occupants evacuated before the plane broke through the ice and sank 20 minutes later. It appeared that this particular aircraft had suffered from false stall warnings a couple of times in the past few days. Investigation revealed that ice had accumulated in the pitot tubes.

Primary Cause

False stall warnings triggered by ice accumulation in pitot tubes.False stall warnings triggered by ice accumulation in pitot tubes.

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