History of Flight
On September 12, 2023, about 2047 Alaska daylight time (AKDT), a Piper PA-18-150, N109T, sustained substantial damage when it was involved in an accident near St. Mary’s, Alaska. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 135 on-demand flight.
Two days before the accident, the pilot ferried a group of five hunters, a guide, and their equipment from the operator’s base in Holy Cross, Alaska, to an airstrip in St Mary’s. The group set up camp next to the runway, which was oriented north-south within hilly terrain about 70 miles northwest of Holy Cross. The day before the accident, the group successfully hunted a moose and coordinated with the pilot to ferry the meat the next day.
On the day of the accident, the pilot arrived at the camp about 1540 and loaded the airplane with the first batch of meat. After takeoff, the airplane made an uneventful climbing right turn over an adjacent ridgeline and continued toward Holy Cross. The pilot returned about 1940 for the second and final load. The meat was strapped into the rear passenger seat area and loaded into the belly pod; moose antlers were tied to the right wing strut, cupped outward and perpendicular to the direction of flight.
The group discussed the weather, noting generally calm north winds but intermittent gusts, stronger at the departure end. The pilot then positioned the airplane for takeoff to the north. Hunters observed a longer ground roll than before; the airplane appeared heavily loaded and labored. At the end of the airstrip, it pitched up, turned sharply right, and flew behind the ridgeline. The airplane did not reappear; the hunters found it had crashed.
A hunter recorded a video showing the airplane beginning ground roll at the southern end, departing uphill. Flaps were retracted; the tail rose as engine power was applied. Ground roll lasted about 530 ft. Immediately after takeoff, the airplane pitched up and rolled right, then returned to wings-level; the engine was heard operating.
Personnel and Aircraft Information
The pilot was first issued his pilot certificate in 1993. At the time of his last FAA medical examination on August 11, 2023, he reported 6,707 flight hours. He was the operator’s sole pilot and had been added to the company’s operating specifications; he underwent a checkride with an FAA inspector ten days before the accident.
The airplane was originally manufactured in 1952 as a Piper PA-18-105. It underwent major alterations via STC in 2013, including a replacement fuselage, new stabilizers, a Lycoming O-320 160-hp engine, belly pod, extended flaps, vortex generators, and 35-inch Alaska Bushwheels. The airplane was involved in a 2017 accident requiring replacement of the vertical stabilizer, rudder, and wing components. As a result of repairs and alterations, almost none of the original airplane remained.
Meteorological Information
The National Weather Service Surface Analysis Chart for 2200 AKDT depicted a low-pressure system and trough near the accident site. The station model closest to the accident showed an air temperature of 42°F, dew point 40°F, cloudy skies, and northwest wind at 10 knots. Witnesses and video corroborated these conditions. Archived low-level wind data from 2045 indicated a 10- to 15-knot north wind over the accident site. The Winds and Temperature Aloft forecast valid for 3,000 ft msl reported north wind at 12-13 knots. The pilot did not request weather information from Alaskan Flight Services.
Wreckage and Impact Information
The runway was at the crest of a hill; terrain fell rapidly to a valley at the northern departure end, then climbed to 400 ft higher within ¾ mile. The airplane came to rest on a 30° downward slope on the other side of the adjoining ridgeline, at 1,210 ft msl, about 10 ft lower and 600 ft east of the departure end. The first identified point of impact was a divot containing right wingtip fragments. The right wing landing light assembly and window frame were nearby. A larger divot matched a main landing gear tire; adjacent was the separated propeller. The engine contained oil; no evidence of catastrophic failure. Residual fuel was in both tanks. Both propeller blades exhibited similar damage: tip twisting, leading-edge nicks, trailing-edge S-bending, and chordwise scratches.
Medical and Pathological Information
The pilot reported high blood pressure and used atenolol; his condition met CACI criteria. He was issued a second-class medical certificate requiring corrective lenses. Autopsy determined cause of death as multiple blunt force injuries. The autopsy identified hypertensive and atherosclerotic cardiovascular disease, including left ventricle thickening and 90% narrowing of a proximal diagonal coronary artery branch. Toxicological testing detected metoprolol in femoral blood and urine; metoprolol is not generally considered impairing.
Survival Aspects
A hunter approached the wreckage and found the pilot conscious with facial injuries. He unbuckled the pilot’s lap belt, extricated him, stabilized him by the airplane, covered him with blankets, and set up a heater. The pilot succumbed to his injuries within about two hours. Damage to the cabin was consistent with a high-energy forward impact; the surrounding structure suffered significant loss of occupiable space. The accident site was outside Medevac range; the closest hospital was in Anchorage, about 400 miles away. A hunter activated a satellite SOS; the airplane’s ELT triggered at impact. An Alaska Air National Guard helicopter arrived between 0130 and 0200 the following morning.
Tests and Research
Video analysis estimated a pitch angle of 16.2° and right bank of 16.6° after rotation. The cargo pod bottom sloped up 13° relative to the fuselage; at maximum pitch, it sloped down 3.2°. Engine speed throughout takeoff was about 2,500 rpm. Engine monitor data for the outbound flight showed 2,600 rpm at takeoff; cruise was 2,450 rpm and 7.3 gph. The accident flight monitor recorded the first 1.5 minutes; CHT and EGTs were stable; the last 5 seconds showed engine speed advancing to 2,000 rpm and fuel flow to 6 gph, consistent with takeoff roll.
GPS data from the previous flight showed a ground speed of 49 kts just before takeoff and 52 kts as terrain dropped; the airplane performed a climbing right turn. In the accident flight, the ground speed was 41 kts when data ended; the wreckage was about 500 ft east southeast of the last recorded position.
Weight and balance: About 520 lbs of cargo (meat and antlers) were weighed post-accident. The airplane’s maximum gross weight was 2,000 lbs for takeoff (after STC). Using pilot weight and estimated 15 gallons of fuel, the airplane was 117.2 lbs over maximum takeoff weight. There was no evidence the antlers interfered with flight controls. FAA Order 8400.34 classifies antlers as a major alteration; the airplane had no approval for such an alteration.