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Float plane inquiry to include crash six years ago

Dec 31 2011

An investigation into why the only engine of a Harbour Air float plane failed at 2,500 feet will include an examination of possible links to the failure of a similar engine six years ago that resulted in a fatal crash.

Flight 215, a de Havilland Otter, was en route from Vancouver harbour to Victoria harbour with a pilot and 11 passengers Thursday when it ran into trouble. The pilot glided the disabled plane down and made an emergency landing in Ganges Harbour at Saltspring Island. No one was hurt.

Officials from the Transportation Safety Board and Harbour Air are trying to find out what went wrong.

"We're working closely with Harbour Air and Pratt & Whitney, the engine manufacturer," Bill Yearwood, the TSB's manager of air investigations, said Friday.

The TSB will not carry out an extensive review, Yearwood said. But he noted that investigators will look at the possible failure of turbine blades on the

PT-6 engine due to metal fatigue, which was a factor in the crash of a Cessna with a similar engine near Port Alberni.

The PT-6 is one of the most popular turboprop engines in its class, used by 6,500 airlines in more than 170 countries, according to the Pratt & Whitney website.

Three people died on Jan. 21, 2006, when a Sonicblue Airways aircraft lost power in its only engine at 9,000 feet, 17 nautical miles from Port Alberni airport. The pilot guided the Cessna through a descent of about 2,500 feet per minute. The aircraft crashed 11 nautical miles from the airport during an attempt to land on a logging road.

The cause of the engine failure of the Harbour Air aircraft has not yet been determined, Randy Wright, vice-president of Harbour Air, said Friday.

Harbour Air has 21 single-engine de Havilland Otters. Wright said he has found the Pratt & Whitney engines to be "very reliable." "I've been here 11 years and never heard of a problem," he said.

In the Port Alberni crash, an examination of the engine by TSB investigators found that all 58 blades in the compressor turbine had broken at different heights.

Their report concluded that the Sonicblue flight crashed because the compressor turbine blade failed due to metal fatigue.

"The subsequent internal damage to the engine was immediate and catastrophic, causing the compressor section to seize because of vibration and bearing damage," the report said.

"Given the internal damage, the pilot would have been unable to restart the engine. This left the pilot with only one option — to attempt an emergency landing without engine power."

Yearwood said the report found the manufacturing process of the PT-6 turbine blades allowed for flaws.

The routes Harbour Air float planes follow are mostly over water, which gives aircraft a place to land in times of trouble, Wright said. "We have the water as a safety valve," he said.

Harbour Air maintenance crews are examining the Otter, which is still in Ganges. It is unclear if repairs will be made there or if the aircraft will be towed to Patricia Bay or Vancouver International Airport.

Emergency water landings can pose risks. Transport Canada requires each passenger to have a life-jacket available. Wright said all passengers are briefed about the location of their life jackets before takeoff. While passengers on Thursday's flight were seen wearing life-jackets while on the coast guard boats, it is unclear whether they were told to put them on before the descent or once the aircraft had landed safely on the water.

In March, the TSB recommended that Transport Canada require passengers on all commercial float planes in Canada to wear life-jackets. It followed the crash of a Seair Seaplanes Beaver plane off Saturna Island in November 2009, in which six passengers died. The pilot and one passenger got out of the plane before it sank in Lyall Harbour.

smcculloch@timescolonist.com

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