Safety measure introduced
Relief for North Sea as helicopter ban lifted
The North Sea’s “workhorse” helicopter can fly again. After an accident off Norway in April last year, the Super Puma H225 and AS332 L2 helicopters were grounded by the UK and Norwegian authorities. They have now lifted the ban, following the introduction of additional safety measures by its manufacturer, Airbus Helicopters.
The authorities had grounded these commercial variants of the Super Puma following a crash of a Super Puma H225 off the coast of Norway in 2016, causing the deaths of thirteen crew and workers.
In its initial investigation the Norwegian Accident and Investigation Board had found that metal fatigue in an H225’s gearbox had caused the rotors to separate from the aircraft and this was subsequently confirmed in the board’s most recent report issued at the end of April this year.
The Norwegian crash appeared similar to an accident off Peterhead in 2009, that was traced back to a fault in the main gearbox of a Super Puma AS332 L2 which had come down killing all sixteen passengers and crew.
These Super Puma variants have been plying their trade in the North Sea for decades and were the workhorse of the offshore industry in taking workers back and forward to rigs.
The European Aviation Safety Authority (EASA) had also grounded the two Super Puma variants but had lifted its ban, meaning it could be flown across Europe with the exception of Norwegian and UK airspace. Germany’s Chancellor Angela Merkel, amongst others, uses a Super Puma to attend international summits.
Since the grounding Airbus has introduced a number of improvements to the aircraft designed to address fatigue failure and provide increased reliability. Measures have included the replacement in all gearboxes with a more resistant part of the type that broke in the Norwegian accident as well as a significant reduction in its life limit from 4000 to 1000 flight hours.
An improved spalling detection system has been introduced, together with a strengthened inspection criteria and equipment allowing a more detailed analysis of particles. This has been augmented by a new quality assurance process that is better able to protect critical components throughout their maintenance history, including a new packaging system equipped with shock sensors.
Airbus claims the improvements raise the bar in safety across the whole helicopter aviation industry to ensure the strictest safety procedures. Immediate passenger flights are not anticipated as each aircraft will have to be submitted to the improvements and fully tested to comply with the granting of airworthiness while re-establishing confidence in them.
The announcement from the Norwegian and UK authorities brings them into line with other aviation boards such as EASA and the US Federal Aviation Administration who had already granted airworthiness certificates to the Super Puma.
The threat of a turf war between different aviation safety agencies has been abated for now but concern must remain that a range of different standards and certifications could provide for variable and confusing decisions.
The clearance of the Super Pumas must come as a relief to the North Sea oil and gas industry, as the aircraft had become its most popular choice and there was only one other helicopter, the Sikorski S92, available as an alternative.
The industry would have faced a logistical and economic nightmare of ferrying staff if that too had been grounded, as it has been in other countries, were it to have been involved in another fatal accident.