Lawyers Call For Flight Safety Improvements

Aviation lawyers acting for victims injured when a Super Puma helicopter came down in the North Sea of Shetland in October 2012 have welcomed the findings of a report into the incident and urged authorities to take on board the key recommendations included.

Irwin Mitchell’s specialist Aviation Law team represents 12 people injured when the CHC-operated Super Puma EC225 was put down in the sea between Shetland and Orkney. Now, a very comprehensive 186 page report from the Air Accidents Investigation Branch (AAIB) has been published. 

The report examines the incident alongside another ditching involving an EC225 in May 2012 and has concluded that both helicopters lost main rotor gearbox oil pressure due to a failure of the bevel gear shaft that drives these critical oil pumps. 

Additionally, for both helicopters the emergency lubrication system was activated which should have enabled them to fly for 30 minutes and reach the nearest airport. However, both experienced a warning that the emergency lubrication system had failed, which forced both crews to ditch the helicopters into the sea. Other key issues included:

• For both helicopters, the bevel gear that drives the gearbox lubrication failed due to fatigue cracks.
• The bevel gear shafts were supposed to have a life span of 20,000 flying hours and are overhauled every 2,000 hours.
• Approximately 63% of bevel gear shafts fitted to EC225 helicopters were scrapped during their first overhaul at 2000 hours.  50% of this scrapping was due to spline wear.
• The bevel shaft for the first accident had only flown 167 hours prior to failure.  The shaft in the second accident had operated for 3,845 flying hours prior to failure.
• The bevel gear shaft had no surface protection, other than oil in the gearbox, to protect it against corrosion.  Corrosion was found inside both shafts and contributed to the fatigue cracks.
• The helicopter manufacturer underestimated stresses in the area of the shaft weld and residual stresses during the welding were not fully taken into account during the design of the shaft.
• Incompatibility between the aircraft wiring and pressure switches in the emergency lubrication system caused an indication that the emergency system had failed, which required the crew to ditch immediately. 

The report also concludes that new cockpit checklists should be used in all helicopters and that changes should be made to the installation of life rafts, as well as that research should be undertaken into the fatigue of metal alloys used in gear shafts.

Irwin Mitchell’s Aviation Law team specialises in representing the victims of air accidents and presently acts for the victims of a number of helicopter disasters, including the fatal Super Puma crash in August last year and the Clutha helicopter crash in Glasgow in November 2013.

Jim Morris, a former RAF Boeing pilot and Partner in the team who is representing victims of the October 2012 ditching, said: 

Read more about Irwin Mitchell's expertise in Air Accident Claims.