History of Flight
On August 8, 2016, about 1651 Alaska Daylight Time, a float-equipped DeHavilland DHC-2 (Beaver) airplane, N95RC, sustained substantial damage during takeoff when the floats collided with the banks of Crosswind Lake, about 30 miles south of Iliamna, Alaska. The commercial pilot and three passengers sustained serious injuries, and three passengers sustained minor injuries. The airplane was registered to and operated by Rapids Camp Lodge Inc under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed. The flight was originating at the time and was destined for King Salmon, Alaska.
The pilot stated that this was his first season flying into Crosswind Lake; he had flown there five times the previous year without needing shuttle flights. He, two fishing guides, and four guests departed Rapids Camp Lodge on the Naknek River around 0800 and landed at Crosswind Lake less than an hour later. The planned return was around 1630. The pilot discussed with the head guide about shuttling half loads to a nearby unrestricted runway. He observed other airplanes taking off westward and considered it manageable. His calculated takeoff water run distance was 1,050 feet, and takeoff distance over a 50-foot obstacle was 2,210 feet; the lake’s shore-to-shore distance along the takeoff path was about 1,800 feet. He did not add a safety margin. During takeoff, wind gusted or changed direction; the pilot stated that reducing power would have made the impact worse, and he should have shuttled half the people.
The right front passenger watched the GPS ground speed (28 mph) during takeoff and saw the bank approaching. The airplane lifted off but struck the bank with a float. A second passenger with over 3,000 flight hours had suggested hugging the shore and accelerating turning out; instead, the pilot pulled 50 yards from shore, reduced to idle, then applied full power. The passenger did not see flap selection and noted his seat belt failed after impact. A witness pilot recorded video showing flaps extended during taxi but retracted during takeoff; the right aileron was deflected down. The witness noted several taxi maneuvers before takeoff.
Personnel Information
The pilot began employment with Rapids Camp Lodge Inc in 2015. His resume included two periods flying DHC-2 floatplanes in Alaska: June–September 2014 (Part 135) and June–September 2012 (Part 135). The operator had no training records available; Part 91 operations did not require an FAA-approved training program.
Aircraft Information
The airplane was manufactured in 1956, certified under Civil Air Regulations 3 and 10. It was equipped with Aerocet 5850 floats (STC, September 2011) and a Kenmore Air Harbor gross weight increase STC (June 2000). The float STC included flight manual supplement correction factors for takeoff distances; the weight increase STC did not. The airplane had shoulder harnesses for pilot and copilot seats but none for passenger seats. The flight manual required flaps in the takeoff position for takeoff; takeoff distance charts only covered takeoff flap configuration. The STC supplement required adding 70% to the takeoff-to-50-foot distance at the accident weight (5,150 lbs). Calculated distances from Aerocet: water run 914 feet, total to 50 feet 1,989 feet. Stall speed with flaps up was 60 mph (52 knots); with flaps in landing position, 45 mph.
Wreckage and Impact
Examination revealed an indentation on the southwest lakeshore from float impact. The wreckage came to rest on a small hill about 100 yards southwest, with the right wing partially in a pond. A trail of fiberglass pieces linked the initial impact to the crash site. The left float was broken; the left wing flap was retracted; the right wing flap was extended but its mechanism broken. The propeller showed damage consistent with engine power.
Tests and Research
GPS data from a Garmin Aera 500 showed the takeoff run starting at 16:40:44 toward the southwest. At the lake midpoint, groundspeed was 40 knots; at the shore, 49 knots; then speed dropped to zero. The data are consistent with the airplane crossing the shore and impacting terrain. Reference to Aerodynamics for Naval Aviators noted that initial flap deflections cause significant increases in maximum lift coefficient, with the first 50% of deflection providing more than half the change.