Cracked gearbox caused EC225 helicopter ditch
Copyright Bond Aviation Services.
After G-REDW (above) made a controlled descent 24 nautical miles off-shore - remaining upright and afloat - Bond suspended all EC225 helicopter flights while it investigated over the weekend in cooperation with Eurocopter experts on site.
The Captain and Co-pilot had made the controlled descent and landed on the sea following standard operating procedures after the helicopter suffered a loss of gearbox oil pressure.
The 12 passengers and two crew-members were safely recovered and returned to Aberdeen later the same day, and after a pre-cautionary examination at Aberdeen Royal Infirmary, returned to their homes.
Bill Munro, Managing Director of Bond Offshore Helicopters Ltd commented, “This was a challenging manoeuvre but one which our pilots regularly practice in our simulator. I would like to personally thank our flight crew for their professionalism in dealing with the situation.”
The AAIB report preliminary engineering investigation is consistent with Bond’s own engineering analysis.
The investigation centred on the activation of the oil pressure warning light that instigated the controlled landing on water of a Eurocopter EC225 at 12:13 on Thursday 10th May. Bond Offshore Helicopters Ltd is committed to the safe operation of the company’s entire fleet including the EC225 and for that reason flights can only recommence once they have completed a detailed analysis of the incident.
The G-REDW helicopter was successfully recovered from the North Sea and placed in the possession of the AAIB who began their inspection on 12th May, actively assisted by Bond in all aspects of that investigation.
The bulletin states that, “An initial visual inspection of the main gearbox has identified a 360° circumferential crack on the bevel gear vertical shaft, in the vicinity of the weld that joins the two sections. As a consequence of this failure, the main and standby oil pump gears ceased to be driven. During this inspection pump gears ceased to be driven. During this inspection it was observed that the lower part of the vertical shaft was displaced downwards by 6 mm.” This preliminary engineering investigation is consistent with Bond’s own engineering analysis.
The maintenance procedures adopted by Bond Offshore Helicopters Ltd. are of the highest standards with safety being the company’s principal concern at all times. It was that focus on safety that was the reason behind the decision to suspend flights of the EC225 having considered the AAIB Service Bulletin.
Bill Munro, Managing Director of Bond Offshore Helicopters said: ”The skill and training of Bond’s pilots has been witnessed at first hand. Our passengers can be confident in Bond as the principal crew change operator in the North Sea”.
In the light of the AAIB interim Service Bulletin Bond Offshore Helicopters Ltd. will continue the flight suspension of the EC225 and now in addition the AS332L2 helicopter. Bond Offshore Helicopters Ltd. is working with Eurocopter as a matter of priority in finding a solution that will enable the helicopters to be returned to service.
Philippa Oldham, Head of Transport at the Institution of Mechanical Engineers said in response to the ditching of a EC225 Eurocopter Super Puma helicopter last week: "There is an urgent need for all companies who use EC225 and AS332L2 Eurocopter Super Puma helicopters to carry out full and thorough inspections of these helicopters.
"It is welcome that Bond Offshore Helicopters has grounded its EC225 and AS332L2 helicopter models, but these models are still used widely by a number of companies and Governments around the world.
"There is an urgent need to review Eurocopter's welding and manufacturing processes, as well as the need to carry out further tests on the gearbox in order to understand how and why the components failed."
