Wednesday, April 1, 2009
Rotorcraft Report: S-92 Ditches Near Newfoundland
COMMERCIAL | OFFSHORE
Seventeen people died after Cougar Helicopters’ Sikorsky S-92 C-GZCH (Cougar Flight 911) ditched in the Atlantic Ocean on the morning of March 12, 2009, while en route to an offshore oil platform. Trouble with the Jeanne D’Arc Breeze was first known when its pilots transmitted a mayday due to a "main gearbox oil pressure problem, according to a preliminary Transport Canada incident report. The pilots told air traffic control that they were heading back to St. John’s, Newfoundland from where they had departed. However, the S-92 ditched 10 minutes later some 40 miles east of St. John’s.
After the ditching, a Provincial Airlines ice patrol plane saw the Jeanne D’Arc Breeze floating upside down, with two life rafts deployed and two people wearing survival suits floating nearby. (All passengers were wearing survival suits as standard procedure.) The sole survivor, 30-year old Robert Decker, was subsequently rescued by Cougar Flight 61, which had been sent to the scene. Listed in critical condition, Decker had regained consciousness at press time. The body of 26-year old Allison Maher was also found floating in the wreck zone.
The Cougar S-92 subsequently sank to a depth of 584 feet to the ocean floor. The remaining 16 bodies were later retrieved from the wreck, as was the voice data recorder, using one or more remotely controlled submersibles from the Atlantic Osprey.
When this story was written, Canada’s Transportation Safety Board (TSB) was planning to recover the wreckage of the Jeanne D’Arc Breeze. Based on video shot by the Atlantic Osprey, "The fuselage, it turns out, has been quite compromised by the impact with the water, said Mike Cunningham, lead investigator with the TSB. "The cockpit area in particular has been quite damaged. The tail boom has been broken off, but the main fuselage or cabin structure is somewhat together, with the main door off.
When asked about the difficulty of recovering the wreckage from this depth, Cunningham cited his agency’s success in recovering the remains of Swissair Flight 111 from a 180-ft depth ten years earlier. "If we can retrieve 95 percent of a large airliner, which was basically in tiny little pieces, I’m pretty confident—unless there’s something I don’t know about—we’ll be able to retrieve what’s down there, he said.
Aided by experts from the NTSB, Sikorsky and GE CT7-8 turbine engine builder General Electric, Canada’s TSB will take the lead in investigating the Cougar S-92 crash. The reported loss of main gearbox oil pressure will be front and center, due to it being reported by the pilots minutes before the heavy-lift twin engine helicopter ditched.
According to a report from the Canadian Press, TSB investigator Cunningham said he was aware of past problems with the oil pressure in the S-92’s gearbox. When asked if this lead will be examined by investigators, Cunningham replied, "It certainly will.
However, there is no smoking gun when it comes to S-92s and oil pressure problems, according to former TSB head of air investigations Nick Stoss. Speaking to Rotor & Wing, Stoss said, "I have reviewed the files, and have not found any specific occurrences directly related to this one.
In fact, based on the Candian Press report cited above, Stoss said he hadn’t seen a case involving a Sikorsky downed by a loss of oil pressure. "Within the safety board, we have not seen that as a problem before, he was quoted as saying.
Still, echoing Cunningham’s words, Stoss said he expects part of the TSB’s investigating team to "concentrate absolutely on the reported oil pressure loss and what might have caused it. This will occur as the S-92’s wreckage is examined in a St. John’s facility.
The loss of the S-92 is a tragedy for the families and friends of those killed in the ditching. From a business perspective, it is crippling to Cougar Helicopters, which "has suspended regular offshore operations until the circumstances surrounding this event have been properly assessed, according to the company’s Web site (www.cougar.ca).
The accident also marks the first helicopter crash since Newfoundland’s offshore oil fields went into operation in 1997.