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Old 29th Jan 2010, 07:38
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choppersky
 
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S 92: grounded because of cracks in gearbox

Newfoundland helicopter grounded because of cracks in gearbox housing

Published on January 28th, 2010 ST. JOHN'S, N.L. - A Newfoundland-based helicopter used to ferry workers to offshore rigs has been grounded because of a hairline crack in the aircraft's main gearbox housing.
The crack was found Tuesday in a mounting foot that is used to attach the housing to the chopper's airframe, a spokesman for Cougar Helicopters Inc. confirmed Thursday.
The helicopter, a Sikorsky S-92A based in St. John's, is the same type of aircraft that crashed off the coast of Newfoundland last March, killing 17 of the 18 people aboard.
Cougar Helicopters also operated that aircraft.
Christian Kittleson, a spokesman for parent company VIH Aviation in Victoria, said it's the second time a Cougar helicopter has been grounded because of a crack in a mounting foot.
The entire gearbox housing on a Halifax-based S-92A Sikorsky was replaced in November, he said.
The housing on the Newfoundland aircraft should be replaced by Friday, he added.
Kittleson said the mounting feet are inspected after every flight in response to a alert service bulletin issued last year by Sikorsky.
"We expected that it would happen again," Kittleson said in an interview. "It was a matter of time."
The problem is considered a "benign issue" that does not compromise the integrity of the aircraft, he said.
On Tuesday, the European Aviation Safety Agency issued a airworthiness directive that requires replacement of another part on the S-92A.
The agency said the choppers' filter bowl assembly in the main rotor gearbox has to be replaced with a newer model.
Kittleson said the company made the changes last month.
The Transportation Safety Board is still investigating the cause of last year's crash in the North Atlantic, about 60 kilometres east of St. John's. However, it has been confirmed that the chopper pilots reported a loss of oil pressure in the gearbox before losing control of the aircraft.
The Canadian agency has said studs broke on the filter assembly, resulting in the loss of a large quantity of oil.
Less than two weeks after the crash of Flight 491, the U.S. Federal Aviation Administration grounded S-92As worldwide with a directive requiring replacement of the studs.
In November, The Canadian Press obtained documents from the European agency that revealed the gearbox of a S-92A had failed a test that required it to run for 30 minutes without oil.
But Sikorsky has said it has proven to aviation authorities that the chances of an oil leak from the gearbox is extremely unlikely and that the installation of a bypass valve resolves the only identifiable cause of a main gearbox leak.
Earlier this month, the families of 15 passengers who died in the crash, as well as the sole survivor of the tragedy, reached a settlement in their lawsuit against Sikorsky.

Newfoundland helicopter grounded because of cracks in gearbox housing - Society - Canada - World - The Moose Jaw Times Herald
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