Sikorsky S-92 Helicopters Grounded

Following the crash of a Sikorsky S-92 off the Newfoundland coast on the 12th of March that killed 17 people, the FAA issued an emergency airworthiness directive in late March grounding all Sikorsky S-92 helicopters.

The FAA said investigators found two main gearbox studs had broken. “Failure of a stud … could result in rapid loss of oil, failure of the main gearbox, and subsequent loss of control of the helicopter,” the FAA said. A similar failure occurred in a July 2008 accident. The failures have been linked to failures of the original titanium studs, which are required to be removed and replaced with steel studs. The helicopters cannot fly until the replacements are complete.

Aviation authorities in Canada and the UK have issued similar directives in relation to the S-92. Sikorsky said that the majority of the worldwide fleet of S-92 helicopters (the company has delivered 91 of them) has already complied with the requirements of the AD. By late March, at least 50 of the global fleet had already completed the retrofit, according to Sikorsky.

The pilots in the Canadian accident had reportedly declared a mayday minutes before the crash, citing a problem with the main gearbox oil pressure. The aircraft appeared to fly a controlled descent from 9,000 feet but lost control at around 800 feet. Only one person survived the subsequent impact with the sea.