History of Flight
On May 24, 2022, at about 1510 Alaska daylight time, a de Havilland DHC-3 Turbine Otter aircraft, registration N703TH, sustained substantial damage when it impacted terrain near Yakutat, Alaska. The pilot and three passengers were seriously injured. The flight was operated by Yakutat Coastal Airlines as a Title 14 Code of Federal Regulations Part 135 on-demand charter, having departed from Yakutat Airport (PAYA) bound for Dry Bay Airport (3AK).
During takeoff from PAYA, the pilot reported that the tail rose slightly then fell back to the runway when he applied forward elevator, which he considered unusual and attributed to an aft-loaded condition. He added nose-down trim and departed without further incident. En route, he noticed vertical tail movement that he ascribed to turbulence.
Approaching 3AK, the pilot entered a left downwind for runway 23. At about 600 ft altitude, he reduced power and extended flaps to 10° abeam the runway end. Turning base leg about half a mile from the approach end, he slowed to 80 mph. On final, the airplane pitched up, prompting him to apply full nose-down trim and extend flaps an additional 10°. On short final, with full flaps selected, the airplane pitched up abruptly to about 45°. The pilot applied full nose-down elevator, verified trim, and reduced power to idle. At about 300 ft above ground level, the airplane stalled; the left wing dropped slightly, and the airplane entered a 45° nose-down dive. After allowing airspeed to increase, he applied full back elevator. The airplane then struck forested terrain near the approach end of runway 23 at an elevation of about 18 ft, resulting in substantial damage to the fuselage, wings, and tail.
A Garmin aera 796 was recovered from the site. GPS data logs indicated the airplane departed at about 1446, climbing and flying southeast for about 18 minutes at GPS altitudes between 492 and 1,280 ft with groundspeeds between 111 and 127 knots. About 2 minutes before the accident, the airplane began a gradual left turn eastward, entering the traffic pattern for 3AK. Groundspeed thereafter varied from 10 to 255 knots. The last fully recorded in-flight data point, at 1509, showed a GPS altitude of 335 ft, groundspeed of 13 knots, and a track of 56°.
Wreckage and Impact Information
The cargo was removed from the airplane after the accident without National Transportation Safety Board (NTSB) knowledge or consent. Postaccident examination of the airframe and engine, including an Electronics International MVP-50T engine monitor, revealed no pre-accident mechanical malfunctions or failures that would have precluded normal operation. Elevator control continuity was established from the control column through cables to the quadrant at fuselage station 427, then via the control rod to the elevators. Rudder control continuity was similarly verified.
Additional Information
Weight and Balance
As a single-engine operation, the flight was not required to carry a load manifest. The pilot stated he computed a weight and balance for the accident flight on paper, but it could not be located after the accident. At NTSB request, the pilot provided two sets of documents indicating cargo and passenger weights and locations; the second set (June 10, 2022) is believed to more accurately reflect actual loading. One passenger reported that freight was weighed on pallets and loaded with his assistance, including a pallet of garbage cans near the front and a pallet of ATV tires, wheels, and a portable sawmill head. Another passenger stated the airplane was partially loaded on his arrival, his weight was not asked, his bags were not weighed, and he sat in the back with a saw at his feet.
According to the airplane's weight and balance data dated March 15, 2017, the basic empty weight was 4,425 lbs with a center of gravity (CG) of 141.1 inches. At maximum takeoff gross weight of 8,000 lbs, the CG range was 135.8 to 152.2 inches. Using the pilot's June 10 documentation, the airplane departed with about 618.8 lbs of fuel and 1,996 lbs of cargo. Assuming a fuel burn of about 360 lbs/hr over about 23 minutes, fuel onboard at the time of the accident was about 480.8 lbs, giving an estimated gross weight of about 7,796.8 lbs. A CG range of about 155.4 to 157.8 inches aft of datum was computed based on two possible fuel loading extremes.
Regulatory Context
The accident flight was conducted under Part 135 on-demand charter rules and the operator's operations specifications (OpSpecs). Per 14 CFR 135.399, the operator was required to comply with takeoff weight limitations in the Approved Flight Manual. Section 135.87 prohibits carrying cargo that obstructs access to or use of the aisle between crew and passenger compartments. Neither Part 135 for single-engine operations nor the operator's OpSpecs required physical documentation of weight and balance for any flight. However, OpSpec paragraph A096 authorized the operator to use actual measured weights for all passengers, baggage, and cargo, or solicited passenger weights plus 10 lbs with actual weights for baggage and cargo. For routine operations, the operator had to follow weight and balance control procedures in the pilot operating handbook.
The NTSB has previously issued Safety Recommendations A-89-135, A-99-61, and A-15-29, asking the Federal Aviation Administration to amend record-keeping requirements of 14 CFR 135.63(c) to include single-engine aircraft. These recommendations were classified "Closed—Unacceptable Action" in 1990, 2014, and 2021, respectively.