http://www.aaib.gov.uk/sites/aaib/publications/formal_reports
http://www.aaib.gov.uk/sites/aaib/publications/formal
A helicopter carrying 18 people ditched in the North Sea after the crew misjudged the position and orientation of the aircraft, a report has found.
http://www.aaib.gov.uk/sites/aaib/publications/formal
A helicopter carrying 18 people ditched in the North Sea after the crew misjudged the position and orientation of the aircraft, a report has found.
The Air Accident Investigation Branch (AAIB) report into the crash in February 2009 said the pilots failed to notice the helicopter was descending into the sea about 300 yards short of a BP oil and gas platform.
The Bond Offshore Super Puma helicopter went down 125 miles east of Aberdeen at around 6.40pm on February 18.
Eighteen people were rescued with only minor injuries.
Workers on the installation raised the alarm after they saw the aircraft hit the water.
A major rescue operation was launched involving an RAF Nimrod, RAF Sea King, civilian aircraft and boats.
The report, published on Wednesday, found both pilots "thought that the helicopter was still above the level of the helideck when it impacted on the surface of the sea" and had the "sensation that the helicopter was high and fast".
It said the crew were likely to be suffering from two types of illusions that warped their perception of where the helicopter was.
The first - a "oculogravic" visual illusion - made them misjudge the position of the platform, and the second, a "somatogravic" non-visual illusion, gave them a false sense of the aircraft's altitude, the report concluded.
It said: "The aircrew were preoccupied with the visual identification of the helideck and were unaware of the continued descent or of increasing pitch up of the aircraft and the consequent reduction in airspeed.
"An erroneous perception that the aircraft was in level flight despite increasing pitch up led to a visual perception that the platform was below them and of the aircraft remaining at a safe height above the sea."
It also found the pilots were focused on the platform, and not the instruments in the helicopter that could have indicated where they were, and two audio height warnings did not activate.
The report also found the "visual illusions" were worsened by low visibility caused by local fog and clouds and reinforced by the reflection of the platform lights on the surface of the sea.
The AAIB found there were no recorded defects that might have contributed to the accident, and the crew were well rested and properly licensed and qualified.
The report made 27 recommendations to UK Transport Secretary Phillip Hammond, including that the Civil Aviation Authority (CAA) commissions a study of visual illusions that could be generated during offshore approaches in poor visibility and at night.
It also said the CAA should take steps to ensure there is an "appropriate defined response" to a height warning.
North Sea helicopter crashed after pilots confused by 'illusions'
A SUPER Puma helicopter, with 18 people on board, plunged into the North Sea only 300 yards from an offshore installation after the two pilots on board became disorientated in the pitch dark and low cloud, a new report has found.
Neither were aware that their chopper was descending towards the sea after a vital height warning system had been switched off, the UK government's Air Accident Investigation Branch (AAIB) said.
It found the crewmen's perception of the position and orientation of their helicopter had probably been affected by the reflection of the platform on the surface of the sea as they approached it.
Both pilots and the 16 oil workers on board the Bond-operated aircraft miraculously survived unscathed after the Super Puma crashed into the icy waters of the North Sea on 18 February, 2009, as they made a landing approach to BP's Eastern Trough Area Project (ETAP) platform, 125 miles east of Aberdeen.
All 18 men managed to scramble into the helicopter's liferafts and were picked up by the crew of a high-speed support vessel and a search-and-rescue helicopter.
Keith Conradi, AAIB chief inspector of air accidents, who wrote the 117-page report, made 27 safety recommendations, including the need for all helicopter operators to make optimum use of automatic flight control systems, the adoption of new lighting standards for platform helidecks, and a review of height warning systems on all North Sea helicopters.
The inspectors also recommended that the Civil Aviation Authority commissions a study into the visual illusions that may be generated during approaches to offshore installations.
The Super Puma EC225, commanded by Captain Mike Tweedie, crashed while on a crew change flight from Aberdeen airport to the ETAP platform. As the helicopter approached the platform, the weather conditions deteriorated, with a cloud base of only 500ft.
The AAIB report said: "The approach was conducted in reduced visibility, probably due to fog or low cloud. This degraded the visual clues provided by the platform lighting, adding to the strength of the visual illusions during the final approach.
"There was no specified night visual approach profile on which the crew could base their approach and minimum heights.
"The visual approach on final approach was possibly confused by a reflection of the platform on the surface of the sea.
"The presence of fog could have introduced a sensation of being too high, and again this aspect of the visual scene could have confirmed an oculogravic illusion."
Bill Munro, Bond managing director, said: "All recommendations immediately relevant to Bond, based on the AAIB's two Special Bulletins in 2009, have already been fully implemented.
The final report does not require any further actions by Bond.
"We await further direction, if any, from the European Aviation Safety Agency and the Civil Aviation Authority, following recommendations relevant to them in the final report."
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