Emergency AD for S-92

The Federal Aviation Administration (FAA) has issued an Emergency Airworthiness Directive (AD) that grounds Sikorsky S-92A helicopters until a certain component in the drive train has been replaced.

The FAA issued the directive March 23, saying titanium mounting studs on the helicopter have to be replaced by steel ones before they can fly again..

The safety directive comes in the wake of a deadly Cougar Helicopter S-92 crash off Newfoundland on March 12 in which 17 people were killed as they headed to an offshore oil platform. The pilot had cited a loss of oil pressure moments before the aircraft suddenly plunged into the ocean.

The helicopter was ferrying workers from Saint John's, Newfoundland to the Hibernia offshore oil platform when it plunged into the Atlantic Ocean 35 miles southeast of Saint John's.

The Transportation Safety Board of Canada (TSB) said investigators found a broken main gearbox filter bowl assembly mounting stud in the accident aircraft.

On January 28, 2009, Sikorsky Aircraft issued an Alert Service Bulletin (ASB92-63-014) indicating that the main gearbox filter bowl assembly mounting titanium studs should be replaced with steel mounting studs. This one-time modification was to be accomplished within the next 1,250 flight hours or within one year of the issue date of the ASB, whichever occurred first.

Sikorsky Aircraft says a majority of the in-service S-92 helicopter fleet worldwide has already complied with the company's notice to retrofit the aircraft's gearbox oil bowl with steel mounting studs. The company expects to have close to 100 percent compliance by the end of this week.

As a safety precaution, contacted all S-92 helicopter operators on March 20 after broken titanium studs were found on the downed S-92 in Canada.

Sikosky said the accident investigation is continuing, and no determination has been made that the broken studs contributed to the accident or if they resulted from it.

The helicopter maker said more than 50 of 91 S-92 helicopter retrofits have already been completed. Sikorsky has made available all the parts and tools necessary for all operators to swap out the studs.

"While the investigation remains ongoing, our priority has been to maintain safety and eliminate any potential risks," said Marc Poland, Vice President of Sikorsky Global Helicopters. "The operators are reacting quickly, and we are doing all we can to encourage full and rapid compliance."