Norwegian investigators have underlined the critical part a rapid crew response played in averting the crash of a Wideroe Bombardier de Havilland Dash 8-100 during a windshear upset over the sea.
The inquiry into the serious incident, during a circling night approach to Svolvaer airport on 2 December 2010, has formally attributed a sudden loss of height to a “powerful” microburst.
Investigation authority SHT says the captain increased engine power and, with the aircraft on the verge of stalling at low height, pushed the control column forward.
The first officer, at some point, instinctively took over the flight controls and pushed the throttles to maximum.
Between them, says SHT, the pilots recovered the aircraft at a height of 83ft.
“A marginally longer reaction time or less-resolute use of engine power would probably have resulted in a collision with the sea,” says SHT.
The inquiry had tried to reconcile two differing perspectives on the situation from the captain and the first officer, particularly regarding whether the first officer’s seizing control was necessary.
But SHT says the factual information has “not been sufficient” for it to determine which of the pilots performed certain actions, and when, nor has it been able to unravel the exact order of events and the effect of individual measures.
As a result, it says, the inquiry has not been able to drawn any firm conclusions over the first officer’s intervention.
The captain might have been exposed to somatogravic illusion as a result of the absence of visual references and a visible horizon, but the inquiry found no reasons to indicate that any sensory illusion affected the crew’s handling of the windshear.
SHT says the incident – which was the subject of a re-opened investigation – is an “important reminder” of the “vulnerability” of aircraft when manoeuvring above featureless terrain at low altitude, particularly in darkness and turbulent air.