The Transportation Safety Board of Canada has released its investigation report on a floatplane crash on Green Lake on Aug. 17, 2000.
Although their findings failed to determine a specific cause, the report identifies a number of factors that likely contributed to the crash, including a leaky float, weight that came close to the maximum, an improper flap setting, and the direction of the plane in relation to the wind.
The injuries to the four passengers were minor, and the pilot sustained injured ribs, however the plane was damaged beyond repair.
According to the TSB report, before the four passengers boarded, the pilot fuelled the plane and pumped approximately 30 litres of water from two compartments of the left float that were known to leak. It was the planes fourth sightseeing trip of the day.
During take-off, the floatplane did not accelerate normally and as a result the take-off run was longer than usual. Within seconds of lifting off, the pilot recognized that the airspeed was lower than usual and "assessed that the floatplane would not climb over the trees on the shore at the end of the lake, so he turned the floatplane to the right to a heading about 90 degrees to the wind direction."
The plane was unable to climb out, and seconds later the pilot turned right again until he was downwind.
"During the second turn, the floatplane descended into the lake, striking the water first with the right float and the right wingtip."
The plane never climbed more than 50 feet off the surface of the water, and during the second turn, the stall warning horn in the cockpit sounded intermittently.
When it impacted the water, both floats were torn off and the aircraft sank into about 15 feet of water. The pilot opened both of the cabin doors, and dived underwater three times to assist the passengers in escaping.
All five occupants of the plane were rescued from the water by a resident with a power boat who had witnessed the crash.
In their "Findings as to Causes and Contributing Factors," the TSB concluded that:
1. The take-off was attempted with the floatplane near its maximum allowable weight and balance and with a flap setting that adversely affected its take-off performance.
2. The performance of the floatplane was insufficient for it to climb and clear obstacles in the flight path, particularly after the floatplane turned downwind and the closing speed with the shoreline increased.
3. The floatplane was at or near the stall speed throughout the flight and, during the second turn, the stall speed increased to equal the airspeed. The resulting stall occurred at a height too low above the water to allow recovery.
In their "Findings as to Risk," the TSB wrote that:
1. The company was operating an aircraft with floats that leaked, which increased the likelihood that the aircrafts performance would be adversely affected.
A previous floatplane accident in Howe Sound the month before had prompted the TSB to change the requirements for float planes to make flotation devices necessary to give passengers the ability to get safely out of the aircraft and into the water.