Flight History
On May 14, 2020, about 2200 Alaska daylight time, a Cessna A185F, registration N5454E, was involved in an accident approximately 72 miles northwest of Nuiqsut, Alaska. The airplane was operated by Webster’s Flying Service as a Title 14 Code of Federal Regulations Part 135 on-demand passenger flight, supporting a research project conducted by the University of Alaska Fairbanks.
The airplane had departed Fairbanks International Airport on May 13, 2020, and was repositioned to a cabin on Teshekpuk Lake in the North Slope Borough. According to the passenger, the “Old Knarl Cabin” on the northwest corner of the lake served as the base of operations. One flight had been completed earlier that day, returning to the cabin at about 1700. After dinner, the pilot checked weather via satellite internet and filed an FAA flight plan. About 1945, they departed for multiple off-airport landing sites near Teshekpuk Lake. Upon return, they overflew the North Slope Borough Wildlife Cabin on the northern shore at an estimated altitude of 200-300 ft above ground level (AGL) and deemed the area unsuitable for landing. The passenger stated that after overflying the cabin and proceeding over the lake, they entered a left turn toward the shoreline for the 4-mile flight back to the Old Knarl Cabin and subsequently impacted the ground. The passenger noted that flat light conditions were a concern over the lake where no terrain features were visible, but off the pilot’s side of the airplane and in the left turn, the cabin and vegetation sticking through the snow provided some definition. Following the accident, the passenger manually activated the airplane’s emergency locator transmitter and sent a distress signal via personal satellite communicator. The passenger reported that the pilot had not voiced any preaccident mechanical concerns and that the plane sounded “good”.
GPS data from the accident flight revealed that the airplane flew along the north shore of Teshekpuk Lake at a GPS altitude of about 136 ft to 232 ft before initiating a left turn and descending. The last fully recorded in-flight data point showed a GPS altitude of 232 ft, groundspeed of 89 knots, on a track of 335°.
Wreckage and Impact Information
Due to the remote arctic location, the wreckage had not been recovered at the time of the report. The accident site was evaluated using photographs provided by the North Slope Borough Police Department. The airplane impacted on its left side in a nose-low attitude and came to rest inverted in an area of flat snow-covered terrain. An area believed to be the initial impact site was marked by disturbed snow and small wreckage debris. The three-blade propeller separated from the engine’s crankshaft and was found within the debris field. Two blades exhibited torsional bending, and one blade showed substantial torsional twisting and S-bending.
Additional Information
The FAA Handbook 8086-23, Seaplane, Skiplane, and Float/Ski Equipped Helicopter Operations Handbook discusses lighting conditions encountered when flying skiplanes, including flat light, whiteout, and nighttime conditions. Flat light occurs due to overcast or broken skies with intermittent sunlight, altering depth perception and potentially causing serious consequences when operating near hilly terrain. The handbook advises that when flat light is encountered, pilots should avoid or discontinue flight operations, especially at unfamiliar strips.