ALAGNAK RIVER, AK, USA
N68084
de Havilland DHC-2
The pilot was making a no-wind takeoff downstream from a 4,000-foot slow flowing river. The takeoff water run for the conditions was calculated at 1,300 feet. The pilot and passenger both reported a partial loss of engine RPM just prior to lift-off from the water. According to the pilot, there was insufficient stopping distance before reaching a river bank. The pilot rotated the airplane off the water below flying speed, cleared the bank, and settled back into the tundra. The pilot stated that a similar loss of engine RPM had happened before, but was considered transient.
On July 19, 1997, at 0845 Alaska daylight time, an amphibious float equipped DeHavilland DHC-2 airplane, N68084, sustained substantial damage when it impacted tundra during a takeoff from the Alagnak River, twenty-eight miles northwest of King Salmon, Alaska. The airline transport certificated pilot and single passenger were not injured. The airplane was operated by Lakeside Industries of Bellevue, Washington, to transport company employees to a fishing lodge. The flight was being conducted under 14 CFR Part 91 in visual meteorological conditions from the Alagnak River to King Salmon. The pilot and passenger stated to the NTSB investigator that they were attempting to takeoff downstream on the slow flowing Alagnak River. Just prior to lifting off the water, they sensed a loss in engine RPM and no loss in manifold pressure. The pilot said he did not have room to abort the takeoff on the water, and rotated the airplane to clear the riverbank. The airplane impacted the tundra, remaining upright. Both wings and floats sustained substantial damage. The pilot stated that there had been two previous RPM drops on takeoff from the King Salmon runway, which self corrected, and were not considered significant. He stated he did not perform magneto checks on the day of the accident. The pilot and passenger estimated 500 pounds of luggage on board. The pilot weighed 173 pounds, according to his second class medical dated May 5, 1997. The passenger weight was estimated at 180 pounds. The pilot stated there was sixty gallons of fuel on board (360 pounds). The empty weight of a representative amphibian DHC-2 on Wipline 2000 floats is 3,890 pounds. The seaplane takeoff distance given in the DHC-2 and U-6A(military DHC-2) operators manuals for the conditions is 1,300 feet. The pilot and passenger estimated the takeoff area to be 4,000 feet long, and downstream. Both occupants stated that the airplane made an uneventful takeoff from the same location one hour earlier.
A partial loss of engine power for an undetermined reason, and the pilot's intentional operation of the airplane with known deficiencies.
Source: NTSB Aviation Accident Database
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