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DHC-8 descends to 25 meters in windshear encounter in Norway
23 November 2016
Screenshot of the AIBN animation

Screenshot of the AIBN animation

A DHC-8-100 aircraft lost altitude and airspeed while on approach to Helle-Svolvær Airport, Norway in darkness as a result of significant windshear, according to investigators.

On December 2, 2010, Widerøe flight WF814 departed Bodø on a domestic service to Helle in Norway. The flight was operated in the hours of darkness with 35 passengers and a crew of three.
The aircraft, a DHC-8-100, was on approach to Helle when it suddenly had a significant loss of both speed and altitude. The flight crew regained control, but the airplane came very low: 83 feet (25 m) above ground. During the recovery the airplane was exposed to high g-force and the engine torque limits were exceeded. The crew aborted the approach and continued to Leknes Airport where a normal landing was performed.

The AIBN investigation indicated that the airplane at low altitude was exposed to significant wind shear (microburst), probably from a Cumulonimbus cloud (CB) in the area. At one point during the chain of events, the First Officer took over the flight controls. The Commander did not oppose this. Apart from agreeing that this happened, the crew has given, in part, different descriptions of the chain of events. Based on the available facts, the Accident Investigation Board has not been able to determine neither which pilot did what, exactly when, and in which order, nor the effects of each action, seen in isolation. It has therefore not been possible to draw any solid conclusions about the significance of the actions of the first officer. The collective actions of the crew did, however, most likely lead to a recovery that was initiated in time to prevent the airplane from colliding with the ground.

The maneuvering to regain control was executed with sparse visual references and without a visible horizon. This investigation has revealed that the Commander was exposed to conditions that could provoke a somatogravic illusion. The Accident Investigation Board has, however, not found evidence to conclude that a spatial disorientation, if any, did have any effect on the Commanders handling of the wind shear.

 

Official accident investigation report

cover
investigating agency: Statens Havarikommisjon for Transport (AIBN) – Norway
report status: Final
report number: SL 2016/11
report released: 23 November 2016
duration of investigation: 5 years and 12 months
download report: SL 2016/11