Sikorsky S-92 helicopter flights were halted after an Alert Service Bulletin was issued.
Helioffshore said the move was a “requirement to undertake a global fleet-wide inspection” but was not a grounding.
However, the helicopters were not expected to be able to return to the skies until the maintenance checks had all been carried out.
Normal flights were expected to resume by noon on Wednesday.
Bristow, CHC and Babcocks all sidelined their S-92 helicopters until the checks had been completed.
The checks were estimated to take up to 11 hours to complete.
Here’s what we know so far.
The decision was made in the wake of an incident at the end of December involving a landing of a helicopter onto a North Sea platform operated by French oil major Total.
At the time a source described how the S-92 took “gouges out” of the helideck, damaged its wheels and spun on the deck of the West Franklin platform when it was forced to land.
The decision to halt the use of S-92s comes after Super Pumas were grounded following a fatal helicopter crash last year which killed 13 people off the coast of Norway.
A mandatory bulletin was issued which means all checks must be carried out before the helicopters can resume their next flights.
There are currently around 30 S-92s in use in the North Sea.
It is understood there are a number of helicopters as part of a “resilience” back-up fleet which could be used to carry flights to and from platforms.
A meeting was held by the Offshore Helicopter Safety Leadership Group (OHSLG) to discuss the matter further yesterday.
Jake Molloy, regional organiser for the RMT union, welcomed the precautionary move.
He said: “It means the aircraft has to be on the ground for some hours but I’m quite sure every worker in the North Sea would rather that rod and that bearing were inspected to ensure that we don’t have a repeat event of December 28.”
Industry body Oil & Gas UK welcomed the move.
Mick Borwell, Health, Safety and Environment Director with Oil & Gas UK, said: “This is the expected response from a helicopter manufacturer when a potential problem has been identified. It is a precautionary measure to ensure the continued safe transportation of the workforce. There will be some short term disruption to operations while these checks are carried out but every possible step will be taken to minimise that. We will continue to monitor events. We support any steps being taken to further ensure the safe travel of the UK offshore workforce.”
In a statement the Offshore Helicopter Safety Leadership Group (OHSLG) said:“This morning Sikorsky released an Alert Service Bulletin (ASB) for the S92 requiring a onetime visual inspection of the Tail Rotor Pitch Change Shaft and Bearing assembly on the world wide S92 fleet prior to the next flight.
“This precautionary inspection is not a grounding, and will allow helicopter operators to carry out the request, which is additional to current routine inspections.
“The operators will have completed the checks on all the aircraft by midday tomorrow (Wednesday 11th January, 2017). It is expected that during the next 24 hours there will be a phased return of aircraft following full return to service testing.
“Clearly the priority is to ensure that both passengers and crew are safe and it is important to maintain a precautionary stance in what is an ongoing investigation. As we receive information we will deliver it to our members, clients and the workforce.”