Helicopter maker Airbus said today it could not have prevented a fatal Super Puma crash in Norway two years ago despite similarities with an accident which killed 16 people near Peterhead in 2009.
Airbus said “neither aviation authorities nor industry” had ever seen the type of crack in the main gear box that led to the incident near Bergen in April 2016.
The French firm also said it had undertaken extensive analysis and introduced a set of safety measures since the crash, allowing Super Puma 225s to return to service worldwide.
But the company acknowledged there are still no Super Pumas flying to oil platforms in the UK or Norway and that “there are no immediate requirements for these aircraft in North Sea crew change operations”.
Airbus released the statement following Accident Investigation Board Norway’s (AIBN’s) publication of its final report into the crash, which killed 13 people, including Iain Stuart, 41, from Laurencekirk.
Investigators said the rotor broke off due to a “fatigue fracture” in one of the aircraft’s gears.
The report authors said: “The accident was a result of a fatigue fracture in a second stage planet gear in the epicyclic module of the main rotor gearbox. Cracks initiated from a micro-pit at the surface and developed subsurface to a catastrophic failure without being detected.
“There are no connections between the crew handling and the accident. Nor is there any evidence indicating that maintenance actions by the helicopter operator have contributed to this accident.
“The failure developed in a manner which was unlikely to be detected by the maintenance procedures and the monitoring systems fitted to (the aircraft) at the time of the accident.”
They found no evidence linking the development of the crack to the involvement of the gearbox in a road accident during transport and prior to installation.
The Super Puma crash off Peterhead in 2009 was also caused by a fatigue fracture in a second stage planet gear.
The aircraft which crashed in Norway on April 29, 2016, was on a return journey from Equinor’s Gullfaks B platform to Bergen Airport when its main rotor suddenly detached.
Flight data showed the CHC Helicopter-operated Super Puma dropped 2,000ft in the final few seconds of its journey.
Witnesses saw an “explosion in the sky” and a spray of components coming from the engine as the rotor came off.
Super Pumas were swiftly grounded and an influx of Sikorsky S-92s was needed to fill the void.
Aviation authorities in the UK and Norway lifted the flight ban on Super Pumas in July 2017.
But they said the aircraft could not return to action until certain modifications and upgrades had been made.
The decision was criticised by trade unionists, who said Super Pumas should remain grounded until a root cause had been identified.
A survey by Airbus found that 62% of respondents would be unlikely to fly in a Super Puma ever again, given the choice.
In October 2017, several MSPs backed calls from unions for a public inquiry into North Sea helicopter safety at a cross-party debate in Holyrood.
Equinor, the new name for Statoil, has said it will never use Super Pumas again.
CHC, which was operating the copter in April 2016, no longer has any 225s in its UK fleet.
It is understood Babcock has no plans to reinstate Super Pumas, regardless of the outcome of the AIBN report.
NHV uses Airbus H175s for UK North Sea oil rig flights from Aberdeen.
Airbus said it welcomed the report’s conclusions and expressed “deep regret” for the accident.
The company said in a statement: “Neither aviation authorities nor industry had ever seen the type of crack in the main gear box that led to the accident.
“Extensive analysis of the accident has led to the development of a set of safety measures, approved by global aviation authorities, which have allowed the H225 fleet to resume flight operations worldwide.
“However, no H225s are flying in the North Sea today and we understand that there are no immediate requirements for these aircraft in North Sea crew change operations.
“There are similarities with the 2009 G-REDL accident (near Peterhead). However, without key evidence at the time, it was impossible to put in place measures which might have prevented the LN-OJF accident in Norway).”
More to follow.