Crash victims challenge S-92 certification

 - March 29, 2011, 5:05 AM

In an open letter to Canada’s minister of transport, the lawyer representing the families of the passengers killed in, and the sole survivor of, the March 2009 crash of Cougar Helicopters Flight 491 has challenged the certification Transport Canada granted to the Sikorsky S-92A in 2005. The accident helicopter, which ditched 30 nm east of St. John’s, Newfoundland, and Labrador, was carrying 18 people. Sikorsky declined to comment on the letter.

The letter was sent a few days after the Transportation Safety Board (TSB) of Canada released its final report (see AIN, March, page 51). Attorney Joe Fiorante asserted that the report does not satisfactorily address questions relating to the S-92’s initial certification. “Transport Canada should never have certified as airworthy a helicopter that could not fly for at least 30 minutes after the complete loss of main gearbox oil,” he stated.

Therefore, on behalf of his clients, he called on Minister of Transport Chuck Strahl to investigate the certification of the S-92. He urged him to “take all necessary measures” to ensure that, in the future, Transport Canada “rigorously enforces the safety standards.” He made it clear that the purpose of his request is to “advance aviation safety” and not for compensation purposes, as his clients’ legal claims have been resolved.

Transport Canada would not comment on the letter to the minister. The administration said that an official answer would be issued within 90 days after the TSB report was released (it was released on Feb 9). The agency also pointed out that it has already started implementing TSB recommendations, such as size selection for passenger survival suits.”

History of Failures

The survivor’s and victim families’ call for an investigation is based on a list of “incontrovertible facts.” First, Flight 491 crashed 11 minutes after, and as the direct result of, a complete loss of main gearbox oil. Canada’s airworthiness regulation requires that the main gearbox be able to run dry (that is, without oil) for 30 minutes. The only exemption is when it can be demonstrated that such a failure is extremely unlikely–no more than once per 10 million flight hours.

The lawyer emphasized that during the S-92’s development, Sikorsky had pledged that the helicopter would have this 30-minute run-dry capability. However, in 2002, the run-dry test resulted in a failure after only 11 minutes. Sikorsky then asserted the S-92 should be certified on the basis that the risk of complete loss of main gearbox oil was “extremely remote.” Both the FAA and Transport Canada accepted the conjecture, the lawyer wrote.

In July 2008, an S-92 suffered a complete loss of main gearbox oil. Fortunately, the aircraft landed seven minutes later. This incident demonstrated that the “extremely remote” assumption was erroneous, according to the lawyer. The S-92 fleet had logged a total 100,000 flight hours at that time. Transport Canada did not take any safety action, the lawyer pointed out.

Yet, after the crash of Cougar Flight 491, Transport Canada issued an AD requiring mandatory replacement of the titanium mounting studs that had failed and caused the oil loss. Sikorsky is looking for a better design. Nevertheless, the lawyer insisted, today the S-92still lacks 30-minute run-dry capability.

The letter also raised a question: “Did Transport Canada succumb to pressure from the FAA or Sikorsky, or did it simply fail to recognize a serious safety/certification issue?” o