New chopper's specs include gearbox requirement
Published Tuesday, April 7, 2009 5:04PM EDT
OTTAWA - The military says specifications for its new Sikorsky naval helicopters include a requirement that the gearboxes be able to run in the event of a serious oil leak.
That assurance follows the deadly crash of a civilian Sikorsky S-92 helicopter off Newfoundland last month that appears to have been caused by a gearbox leak.
The new naval helicopter is a variant of the S-92.
The Defence Department said its Cyclone helicopters will have to have a "run-dry" capability before they will be accepted from Sikorsky.
"The run-dry capability requirement for the CH-148 gearboxes, as stipulated in the solicitation document, is included in the maritime helicopter contract," a department spokesman wrote in an email Tuesday.
Sikorsky won the helicopter contract in 2004. A series of delays have put off the first delivery to 2012 from 2010. The initial delivery target was 2008.
Defence said the U.S. manufacturer is working on the gearbox system.
"Sikorsky has undertaken considerable work to define how to best meet this requirement and the final gearbox design will be completed and tested against the contract requirements before acceptance and delivery of the helicopter."
The $5-billion helicopter project is to deliver 28 aircraft for use on Canadian warships. The price tag includes avionics, electronics, 20 years of in-service support and a training facility.
News reports said the civilian S-92 that crashed, killing 17, won an exemption from the "dry-run" requirement by submitting evidence that the likelihood of a catastrophic oil loss was extremely remote.
Sikorsky denies that, saying there is no dry-run requirement for civilian helicopters and that the S-92 met all applicable requirements.
"The aircraft has a bypass system that isolates leaks and re-circulates oil in the main gearbox once activated by the crew," the company said in a statement. It said licensing agencies, including Transport Canada, accepted that as meeting lubrication requirements.
Jim Astley, a retired aviation engineer who led the design of Lockheed Martin Corp.'s competing bid for the navy helicopter in 2004, said the Sikorsky flight manual requires the bypass to be activated five seconds after a warning light goes on.
He said if that doesn't occur, the oil will be gone.
"The concern is that it may have been accepted by the FAA, but it doesn't solve the problem," said Astley, now retired and living in Ottawa.
"If you lose all the oil in your gearbox, you're done . . . if the gearbox has already lost all its oil, then having a bypass route for the oil doesn't really help you".
The S-92 has also had problems with titanium mounting studs on the gearbox, a key component which links engines to the rotors.
In January, it recommended that operators replace the studs with steel ones and said the modification had to be done within the next 1,250 flight hours or within a year of the bulletin being issued.
Canadian investigators looking at the Newfoundland crash found the studs, which hold the main oil-filter bowl, were broken.
The U.S. Federal Aviation Administration last month ordered the helicopters grounded while replacement studs are installed.
Breakage of a mounting stud "could result in rapid loss of oil, failure of the main gearbox, and subsequent loss of control of the helicopter," the FAA said in its order.