A confidential draft of the report is circulating among experts chosen by the board for technical input.
Board spokesman John Cottreau says each reviewer has at least 30 days to make comments that will each be answered in writing.
The process is time consuming and Cottreau would not speculate on when the final report will be made public.
Cougar Flight 491 crashed into the North Atlantic on March 12, 2009, killing 17 of 18 people onboard.
Cougar is suing Sikorsky Aircraft Corp., claiming it misrepresented how long the helicopter could fly without oil in its main gearbox.
The claim has not been proven in court and statements of defence have not been filed.
Two weeks after Flight 491 went down, the Transportation Safety Board said two of three titanium studs that secure the oil filter bowl assembly to the helicopter’s main gearbox broke in flight.
The snapped studs resulted in a loss of oil pressure in the S-92 helicopter’s main gearbox.
Eleven minutes after the pilots reported the problem and headed for the nearest landfall, the chopper pitched into the sea.
“By promoting and advertising the S-92 as having a ’30-minute run-dry’ capacity, Sikorsky fraudulently misrepresented to buyers and operators the airworthiness and flight safety of the S-92,” says the statement of claim filed by Cougar and eight insurance companies in the Supreme Court of Newfoundland and Labrador.
“Such false pretense was made solely for the purpose of earning sales revenue” and showed “callous disregard for the risk of death or injury to crews and passengers of the S-92.”
Sikorsky has declined to comment on the litigation. It settled out of court with sole survivor Robert Decker and the families of the other victims earlier this year.
Details of the compensation offer were not publicly released.
The two pilots were taking 16 workers to the Hibernia and White Rose oilfields more than 300 kilometres east of St. John’s.