North Sea flights hit as Sikorsky S92 helicopters grounded amid safety concerns
All Sikorsky S92 helicopters have been grounded amid concerns over safety, causing disruption to North Sea flights.
The helicopters have been recalled to base to undergo maintenance and inspection work.
The recall, issued by the manufacturer, could impact upon flights in the region for several days.
The move follows an incident involving an S92 on a North Sea platform last month.
The helicopter was landing on the West Franklin platform on December 28 when it left significant gouge marks on the deck.
A spokesman for Aberdeen International Airport confirmed on Tuesday: "All S92 helicopters have been recalled following a safety instruction.
"We are aware of a safety alert that has been issued for all S92 helicopters and are anticipating a potential impact on helicopter operations over the next few days until essential maintenance has been carried out.
"We will support the operators as much as possible through this disruption."
The alert, issued on Tuesday morning, only affects the S92 model.
Sikorsky confirmed it has issued a notice known as an alert service bulletin, which relates to the tail rotors of the aircraft.
It demands a visual inspection of that part of the aircraft on the S92 fleet before the next flight.
A US-based spokeswoman for the manufacturer said: "Safety is our top priority and Sikorsky is working closely with our customer and investigative authorities to determine the root cause of the loss of tail rotor authority in the December 28 installation landing.
"Although the investigation into the December 28 incident has not been completed, Sikorsky released an alert service bulletin on January 10 to define additional interim inspection requirements for the S-92 tail rotor pitch change shaft (PCS).
"Those procedures include an off-aircraft check of the PCS bearing and that check must be done before next flight with some leeway for getting back to base."
She said the firm is committed to keeping its customers informed.
"We will further communicate findings if the investigation reveals any safety or airworthiness issues that affect the S-92 helicopter fleet," the spokeswoman added.
The alert on a model thought of as the "workhorse" of the North Sea could disrupt operations possibly until the end of the weekend, industry sources fear.
Step Change in Safety, an organisation which campaigns to make the UK the safest place to work in the worldwide oil and gas industry, said Sikorsky's decision will result in some short-term delays.
Executive director Les Linklater said: "The decision made by Sikorsky is a precautionary measure to ensure continued safe flight operations and we are aware that helicopter operators are working to assess the impact of this requirement, while investigating all opportunities to limit the effects on the flying program.
"Currently, the duration of the inspections is expected to take up to 11 man hours, which means this will cause some short-term delays.
"We are in close communication with trades unions, helicopter operators and the Civil Aviation Authority."
The Civil Aviation Authority (CAA) stressed the current move was purely a manufacturer's recall, not a regulatory decision.
A spokesman said they are aware of the situation and are discussing matters with the three firms which operate S92s in the North Sea region, CHC, Bristow and Babcock.
A spokeswoman for oil and gas firm Shell said their flying was likely to be "significantly impacted" as a result of the decision and work was being carried out on alternative flight provision.
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 that rod and that bearing were inspected to ensure that we don't have a repeat event of December 28."