TSB chopper crash report cites 16 factors

[burhead1]

http://www.ctv.ca/CTVNews/TopStories/20 ... ay-110209/
CTV.ca News

Date: Wed. Feb. 9 2011 4:47 PM ET

The Transportation Safety Board says there were 16 factors that contributed to the crash that caused the death of 17 people in an offshore helicopter crash off Newfoundland two years ago.

If any one of those factors were removed from the equation, the crash likely would not have occurred, said TSB Chair Wendy Tadros.

The TSB released its final report Wednesday into the cause of the deadly crash. It reiterated earlier findings that massive mechanical failure was caused by a loss of oil pressure in the chopper's main gearbox due to faulty titanium studs.

However, Tadros said there was also a "complex web of 16 factors at play that day."

The crew members on the chopper, for instance, were trained to deal with a loss of oil but were under the impression they had 30 minutes to get to land.

They were also trained to watch for temperature increase and for vibrations as a secondary warning system. But because the oil loss was so catastrophic, those did not occur, and the crew believed it was dealing with a faulty sensor and still had oil.

The failure of the chopper's emergency floatation system also played a major role. Tadros said all passengers and crew were still alive when the chopper hit the water, but only two were able to escape the wreckage before it sunk.

Tadros said the TSB is recommending the following:

Noting that nothing is more precious than time in an emergency, she said choppers should have a full 30 minutes, or more, of flying time before functions fail after a loss of oil.
Additionally, the FAA should look into whether 30 minutes is long enough in extreme operating environments such as the North Sea.
If a helicopter has to ditch in rough waters, its emergency floatation system must be able to keep it afloat long enough for everyone to evacuate.
All helicopter flights across Canada where survival suits are required should have emergency underwater breathing devices incorporated in the suits -- something that is already being done in Newfoundland.
"All 17 victims of Flight 91 died of drowning. It is the number one cause of death in ditching or crashing accidents," Tadros said. "We've learned cold water does more than cause hypothermia. Cold water makes it almost impossible to hold your breath."

She said those who are required to take potentially dangerous flights to get to work should have every possible safety precaution working in their favour.

"We have to do all we can to ensure their safety, that's why we've dedicated so much time and effort to this investigation to make sure the legacy of this accident is improved safety for all those who must fly over water," Tadros said at the news conference.

Danny Breen's brother, Peter died in the crash.

"It's good that the facts of the situation and the details are all out on the table so we can consider them and try to make whatever sense of them we can," he told CTV News Channel of the report. "It was a very difficult report to read, more difficult than I thought it would be."

Breen said he didn't think search-and-rescue was adequately covered in the report, however.

"You have to remember that the water was 0.2 degrees Celsius at the time of the crash, so it's a very difficult environment you are working in," he said.

"The time that search and rescue was deployed . . . is a critical factor, and I don't think it was adequately covered in the report."

The Sikorsky S-92 chopper was ferrying workers to an offshore oil platform when it crashed on March 12, 2009.

Robert Decker was the only survivor. He managed to escape the chopper and was later found floating in a leaky survival suit in the frigid Atlantic.

Decker suffered from multiple broken bones including a broken back from the crash, but has now fully recovered.

The Transportation Safety Board has already indicated it was a loss of oil pressure that brought the helicopter down. Cougar Helicopters, the operator of the aircraft, had been told to replace titanium studs on the gearbox, but was given 12 months or 1,250 flying hours, to do so.

An investigation into the crash wreckage showed two of three studs had broken, causing the loss in oil pressure.

Wednesday's report was expected to probe the chopper's supposed ability to continue flying for 30 minutes after a loss of oil. That window should have allowed the helicopter to reach land, but an earlier inquiry showed the helicopter went down 11 minutes after losing oil pressure.

Cougar Helicopters and eight insurance companies have launched a lawsuit against Sikorsky Aircraft Corp., claiming the company used a flawed analysis to make the 30-minute run-dry claim.

None of the allegations have been proven in a court of law.

The titanium studs on the main gear boxes in S-92 aircraft have now been replaced with steel studs.

[2.5milefinal]

http://www.tsb.gc.ca/eng/rapports-repor ... 9A0016.pdf

[ktcanuck]

Having been an aero engineer involved in proof of airworthiness I read the sections on the main gearbox and its design impact on certification with great interest. I imagine the lawyers see lucrative times ahead.

[55+]

Check this out actual audio recordings from CZQX and the chopper..............

http://www.theglobeandmail.com/news/fin ... le1905064/

[flyincanuck]

God that makes my stomach turn.

[ktcanuck]

And so it begins:

http://www.cbc.ca/news/canada/newfoundl ... 2-224.html

[angry inch]

CBC interview with Robert Decker (sole survivor of Cougar crash)...

http://www.cbc.ca/video/news/audioplaye ... 2170133533

[CpnCrunch]

Regarding the lack of run-dry capability: Sikorsky managed to get it certified even though it doesn't have a 30-min run-dry capability because they said it was an 'extremely remote' change of it ever running out of oil:

http://www.theglobeandmail.com/news/nat ... 835390.ece

With only 100 S-92s sold worldwide, there has already been one documented case of total oil loss, and it is the leading theory in last month's S-92 crash off the coast of Newfoundland. “Two cases in five years is not what I would call an extremely remote chance,” says an aerospace engineer who has followed the S-92. “One in five million is remote.”

I guess it's up to the operators to decide whether they want to continue using this helicopter, or replace it with something safer.