The Globe and Mail newspaper in Toronto gained access to documents that showed "the S-92 couldn't meet a specification that calls for the main gearbox to run for half an hour without oil" in the event of a leak.
Yet certification documents filed with the Joint Aviation Authorities and seen by the newspaper show the U.S. Sikorsky company "demonstrated that a complete loss of gearbox oil was nearly impossible."
Early stages of the investigation into the Canadian crash indicate the craft experienced a sudden and complete loss of power and plunged into the Atlantic Ocean from about 900 feet while shuttling oil platform workers.
The only other known case of a total oil loss on an S-92 ocurred last summer when a helicopter in Australia made a forced landing that took 8 minutes, the newspaper said.
Sikorsky representatives told the newspaper they couldn't comment because the Canadian crash investigation is continuing.