Safety checks have been ordered on certain models of North Sea helicopters after a loose bolt was found which could lead to the in-flight loss of control of the aircraft.
The move comes after a routine inspection on two separate helicopters found issues with the fitting of the tail mounted horizontal stabilizer.
On one aircraft one of the bolts that attaches the small wing like device was found to be broken in its threaded section and kept in place by the sealant alone.
European aviation safety watchdog EASA has issued an airworthiness directive, ordering operators of the Airbus H175 aircraft to carry out checks on their aircraft.
Only a small number of H175s are in service in the UK North Sea. NHV has three at its base in Aberdeen, while CHC Helicopter took delivery of its first H175 for use in offshore oil operations in August.
EASA has ordered operators to fit brackets on the horizontal stabilizer to prevent the affected bolts from moving if they become compromised.
Repetitive visual inspections of the bolts are also to be carried out and any damaged parts are to be replaced.