Norway grounds all Airbus H225 helicopters following fatal North Sea crash
02 June 2016
The Norwegian Civil Aviation Authority has decided to suspend the use of all Airbus Super Puma H225s in Norwegian service, including search and rescue helicopters, after Accident Investigation Board Norway (AIBN) called on the European Aviation Safety Agency (EASA) to take “immediate action” to ensure the aircraft was safe.
The call came after AIBN published a report which found evidence of fatigue in gear box parts retrieved from the remains of the H225 involved in a crash off the island of Turøy on 29 April, which killed all 13 crew and passengers.
The helicopter type had already been suspended from regular traffic in Norway following the incident, however it was still being used search and rescue assignments. Statoil uses the H225 for SAR emergency services from the Oseberg Field Centre, Statfjord B and Sola.
The Norwegian oil group said it would ensure alternative cover was provided following the grounding of the type.
The Super Puma was travelling from the North Sea Gullfaks B oilfield, about 74 miles off the Norwegian coast, when it crashed en route to Flesland Airport, Bergen. Witnesses said the main rotor became detached from the helicopter prior to the crash.
AIBN’s preliminary report published on June 1 detailed fatigue in the gearbox and a “catastrophic failure”, rendering early safety warnings “not effective”.
The AIBN report read: “Among the recovered parts were two pieces which together form approximately half a second stage planet gear. Examinations of these parts have revealed features strongly consistent with fatigue. The fatigue appears to have its origin in the outer race of the bearing (inside of the gear), propagating towards the web of the gear teeth. There is sign of spalling in front of the fracture surface.”
The report said it felt the “findings to be of such significance that it has decided to issue the following safety recommendation to ensure the continuing airworthiness of the Main Gear Box (MGB)”.
It added: “It cannot be ruled out that this signifies a possible safety issue that can affect other MGBs of the same type. The nature of the catastrophic failure of the LN-OJF main rotor system indicates that the current means to detect a failure in advance are not effective.”
The Super Puma, a workhorse of the oil industry, has now been completely grounded in both Norway and Britain. Investigators have ruled out human error, saying the crash was caused by a technical fault.
Results of the investigation have potential implications for the Super Puma programme following earlier accidents.
On June 2 EASA issued an emergency bulletin, however, focusing on a different problem.
It said checks on the rest of the Super Puma fleet had revealed problems with struts that fix the rotors, including bolts tightened incorrectly or washers in the wrong position. It ordered all attachments replaced before the next flight.
It was not immediately clear whether EASA also planned another bulletin responding to Norway's gearbox findings.
Previous Super Puma incidents linked to gearbox problems included a 2009 crash off Peterhead, Scotland, in which the rotor also flew off and 16 people died. Airbus Helicopters told operators in a bulletin this week that there were "significant elements" differing from the 2009 crash.