History of Flight
On August 11, 2022, at 1152 Alaska daylight time, a Piper PA-12 airplane, registration N3937M, was substantially damaged when it crashed near Arctic Village, Alaska. The pilot, who was on a solo hunting trip, was fatally injured. The flight was operated under Title 14 Code of Federal Regulations Part 91 as a personal flight. The pilot had sent messages between 0930 and 1030 indicating he was preparing to depart the area. No distress calls or other communications were reported. The wreckage was discovered the following day at about 1140 by a pilot flying nearby, located about 2 nm west of Marsh Strip, a gravel airstrip adjacent to the Marsh Fork of the Canning River. The pilot who discovered the wreckage reported significant wind shear with sustained winds of at least 20 kts, gusting to at least 30 kts, and described the gusts as violent. Another pilot who flew northbound over Marsh Strip at about 1430 on the day of the accident reported very turbulent wind conditions.
Data from the pilot's GPS showed that at 1149, the airplane departed Marsh Strip to the south and made a right turn into a valley. The flight track continued west up the valley at an altitude of about 300 to 400 ft above ground level for about 2 nm, then made a sharp left turn and descended to the ground.
Aircraft Information
The accident pilot had stored fuel at Chandalar Lake Airport (PALR) for his hunting trip. On August 7, 2022, he arrived at PALR and refilled the airplane with two 5-gallon containers of fuel (10 gallons total). Three additional 5-gallon containers remained, covered and in good condition. Based on GPS data and fuel information, the estimated fuel onboard at takeoff was about 14.15 gallons.
The most recent weight and balance for the airplane was completed on February 18, 2020, with an empty weight of 1,191.00 lbs. The mechanic who performed the weight and balance stated that he transposed the maximum gross weight of 1,838 lbs from previous paperwork, but he was not aware of any modifications that would increase the maximum gross weight; thus, the correct maximum gross weight should have been 1,750 lbs. A postaccident weight and balance calculation, including fuel, indicated the accident flight payload was about 620 lbs. The airplane's actual useful load was 559 lbs, not the 647 lbs listed in the most recent weight and balance, meaning the airplane was 61 lbs over maximum gross weight during the accident flight.
Wreckage and Impact
The accident site exhibited an initial impact crater about 20 yards west of the airplane, with the wreckage path oriented on a heading of 064°. The main wreckage came to rest facing southeast and remained mostly intact. The cockpit area was crushed upward and aft. The airplane was canted left, with the left wing folded back underneath the fuselage. The left wing had leading edge crushing to the wing tip, and the right wing sustained outboard leading edge damage and was bent upward near midspan. Flight control continuity was confirmed from all surfaces to the cockpit controls through a few impact separations. The flaps were partially extended, and the pitch trim jackscrew corresponded to a full nose-up position. The payload had become dislodged, and its exact preimpact location could not be determined.
The pilot's seat floor mounts were separated from the fuselage. The pilot's restraint system consisted of a 3-point lap belt and shoulder harness. The lap belt was secured around the pilot with both tongues engaged in the buckle, and the shoulder harness remained attached to the roof mount but had pulled loose at the Y-junction stitching. First responders observed the shoulder harness loose upon arrival.
There was a strong smell of fuel near the front of the airplane; the fuel tanks and lines were compromised. The gascolator was intact and about half full of fuel, which tested negative for water contamination. The engine remained partially attached to the engine mounts and firewall, and the cowling had separated. The engine sustained minimal impact damage. The two-bladed propeller remained attached to the crankshaft flange, with blades displaying leading edge gouging, torsional twisting, chordwise striations across the cambered surface, and trailing edge "S" bending. Examination of the airframe and engine revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation.
Flight Recorders
The Garmin aera 660 GPS was in good condition, and data were downloaded normally. The data included 27 track logs from June 12, 2022, to August 11, 2022. The accident flight recording started at 19:46:31 UTC and ended at 19:52:52 UTC on August 11, 2022. The GPS stored several user-set waypoints, including "MSHFRK 02" near the beginning of the accident recording. Initially, data consistent with taxiing lasted about half a minute at GPS altitudes between 2,780 and 2,790 ft. At 19:49:07 UTC, the airplane began accelerating, departed to the south, and made a sharp right turn west. Throughout the flight, GPS groundspeed ranged from 40 to 50 kts. The maximum GPS altitude of 3,412 ft was reached at 19:52:06, after which the airplane made two turns. The groundspeed increased to 70 kts at 19:52:21 before decreasing to 0 kts when the data ended at 19:52:52 UTC, about 2.25 nautical miles west of the initial data point.
The JPI Engine Data Monitor EDM-700 sustained minor impact damage but was operable, and data were downloaded normally. The recording contained multiple hours of data over several power cycles, with the accident flight being the last. The data showed a constant and steady increase in cylinder head temperatures (CHT) and exhaust gas temperatures (EGT) until the end of the recording. No anomalies were noted.