S-92 Crew Reported “Zero” MGB Oil

 - March 30, 2009, 5:53 AM

Minutes before a Cougar Helicopters Sikorsky S-92 fell into the Atlantic March 12, one of the pilots radioed that the helicopter had “zero” main gearbox (MGB) oil pressure. Two pilots and 16 offshore oil workers were aboard the helicopter when it either crashed or ditched 47 miles East of St. John’s Newfoundland. The S-92 was 40 minutes into a flight outbound to the Seas Roses and Hibernia platforms when the crew declared an emergency and turned back to shore. Eight minutes later it entered the water. One survivor and one body were recovered. The other 16 are missing and presumed dead.

The main wreckage was located in 360 feet of water and salvage crews were optimistic that they could raise it intact and recover the flight recorders. The six-mile long debris field included one sponson, several doors and an interior bulkhead, suggesting that the S-92 impacted the water at a high rate of speed. A rescue plane over the scene 25 minutes after the crash reported seeing the fuselage floating inverted.

This is the second crash of an S-92 and the first likely caused by a mechanical failure. However, several S-92 operators have reported MGB problems including overheating and loss of oil pressure. This included a near-ditching of a Norsk Helicopters S-92 after an MGB oil pump failed. Since 2005, the FAA has issued several Airworthiness Directives covering the S-92’s MGB scavenge pumps and housing assembly, main transmission assembly mounting bolt, shaft and bearing assembly and tail gear box output housing.