ALL Sikorsky S92 helicopters have been grounded and recalled to base to undergo maintenance and inspection work amid concerns over safety, causing disruption to North Sea flights.

The manufacturer issued the recall notice, which could affect flights for several days, following an incident on a North Sea platform last month involving an S92. The aircraft was landing on the West Franklin platform, about 130 miles east of Aberdeen, on December 28 when it left significant gouge marks on the platform deck.

Operators have been told to carry out the checks, which relates to the tail rotors assembly, immediately. They are expected to take several hours per aircraft.

A spokesman for Aberdeen International Airport confirmed yesterday: “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 warning, known as an alert service bulletin, was issued yesterday morning and only affects the S92 model.

Sikorsky confirmed it had issued the notice, which demands a visual inspection of the tail rotors 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 S92 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 was committed to keeping its customers informed.

“We will further communicate findings if the investigation reveals any safety or airworthiness issues that affect the S92 helicopter fleet,” the spokeswoman added.

The Maritime and Coastguard Agency (MCA) said its S92s, which were operated by Bristow, would return to service throughout the day.

“The Inverness-based helicopter has already been brought back into service for lifesaving work and we are negotiating a limited return to service at other bases in the same manner,” said a spokesman.

Industry sources fear the alert on a model which is thought of as the “workhorse” of the North Sea, could disrupt operations possibly until the end of the weekend.

Step Change in Safety, an organisation that 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 programme.

“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.”