er340790
29th Jul 2008, 14:01
Frigid weather blamed for airplane crash:
Frozen water drops clogged a bush plane‘s fuel supply and reduced engine power, leading to a crash in the bush southwest of Armstrong last November, the Transportation Safety Board has found.
Using an icing inhibitor in the fuel likely would have prevented the fuel system blockage, the board said in a report about the Nov. 30 crash.
The pilot‘s leg was broken and his two passengers suffered minor injuries. The trio spent seven hours in -33 C weather until they were rescued.
The company that owns the four-seater Aero Commander 500B aircraft, Hicks and Lawrence, has already changed its policies to require using cold weather fuel additive at freezing temperatures, the safety board noted in its findings. Hicks and Lawrence, which supplies birddogs and aerial fire surveillance to the province‘s forest fire management program, also plans to introduce mandatory training on the use of icing inhibitors this fall.
Last November, the three pilots flew from the company‘s hangar in Dryden en route to Geraldton, where they were to pick up another plane stationed there for the summer and take it to the company base in Kenora.
A half-hour into the flight, the engine fuel flow readings started fluctuating. The crew upped the engine mixture controls to the full rich position, but 10 minutes later the right engine fuel flow decreased and the engine began to lose power.
The crew decided to divert to Armstrong. Three minutes later the left engine fuel flow began dropping.
Soon both engines were at or near idle power despite the throttles being wide open.
The pilot aimed for a marshy, snow-covered clearing 37 kilometres southwest of Armstrong.
He landed the small plane on its belly and slid for nearly 50 metres before the right wing clipped a tree, spinning the plane sideways. The pilot was thrown against the door.
Later that day, military search and rescue technicians parachuted into the spot and looked after the three downed men until Ministry of Natural Resources helicopters could pick them up.
The fuel supplies to both Lycoming engines were blocked with ice, the safety board found.
Before taking off, the crew had drained the sumps and noted no visible water, but sitting inside a heated hangar would have increased the fuel‘s saturation level, leaving a higher amount of water suspended in the fuel, the report said.
The fuel distributor valve‘s location, combined with the Aero Commander‘s engine cowling configuration, exposes the valve directly to the outside air‘s cooling blast, the board noted.
In warm temperatures that is desired, but in extreme cold, the exposure can freeze water that can block the fuel stream – and result in loss of engine power.
High altitude testing in the 1970s found that adding a de-icer to the fuel can reduce the problem.
Hicks and Lawrence uses its aircraft in summer, and rarely in winter, the report noted, and the company didn‘t have procedures for using the fuel additive icing inhibitor in winter operations.
Frozen water drops clogged a bush plane‘s fuel supply and reduced engine power, leading to a crash in the bush southwest of Armstrong last November, the Transportation Safety Board has found.
Using an icing inhibitor in the fuel likely would have prevented the fuel system blockage, the board said in a report about the Nov. 30 crash.
The pilot‘s leg was broken and his two passengers suffered minor injuries. The trio spent seven hours in -33 C weather until they were rescued.
The company that owns the four-seater Aero Commander 500B aircraft, Hicks and Lawrence, has already changed its policies to require using cold weather fuel additive at freezing temperatures, the safety board noted in its findings. Hicks and Lawrence, which supplies birddogs and aerial fire surveillance to the province‘s forest fire management program, also plans to introduce mandatory training on the use of icing inhibitors this fall.
Last November, the three pilots flew from the company‘s hangar in Dryden en route to Geraldton, where they were to pick up another plane stationed there for the summer and take it to the company base in Kenora.
A half-hour into the flight, the engine fuel flow readings started fluctuating. The crew upped the engine mixture controls to the full rich position, but 10 minutes later the right engine fuel flow decreased and the engine began to lose power.
The crew decided to divert to Armstrong. Three minutes later the left engine fuel flow began dropping.
Soon both engines were at or near idle power despite the throttles being wide open.
The pilot aimed for a marshy, snow-covered clearing 37 kilometres southwest of Armstrong.
He landed the small plane on its belly and slid for nearly 50 metres before the right wing clipped a tree, spinning the plane sideways. The pilot was thrown against the door.
Later that day, military search and rescue technicians parachuted into the spot and looked after the three downed men until Ministry of Natural Resources helicopters could pick them up.
The fuel supplies to both Lycoming engines were blocked with ice, the safety board found.
Before taking off, the crew had drained the sumps and noted no visible water, but sitting inside a heated hangar would have increased the fuel‘s saturation level, leaving a higher amount of water suspended in the fuel, the report said.
The fuel distributor valve‘s location, combined with the Aero Commander‘s engine cowling configuration, exposes the valve directly to the outside air‘s cooling blast, the board noted.
In warm temperatures that is desired, but in extreme cold, the exposure can freeze water that can block the fuel stream – and result in loss of engine power.
High altitude testing in the 1970s found that adding a de-icer to the fuel can reduce the problem.
Hicks and Lawrence uses its aircraft in summer, and rarely in winter, the report noted, and the company didn‘t have procedures for using the fuel additive icing inhibitor in winter operations.