Accident Overview
On November 29, 2019, about 1911 Alaska standard time, a Piper PA-31-350 airplane, registration N4087G, was destroyed when it was involved in an accident near Cooper Landing, Alaska. The three occupants—the airline transport pilot, a flight nurse, and a flight paramedic—were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 135 air ambulance flight by Medevac Alaska through its charter provider Security Aviation, designated as flight SVX36.
Flight History and Dispatch
Dispatch records indicate that on November 29, Providence Seward Medical Center emergency clinic personnel contacted multiple air ambulance companies for a "weather check" regarding possible transport of a patient from Seward Airport (PAWD) to Ted Stevens Anchorage International Airport (PANC). Guardian Flight declined at 1624 due to limited daylight hours; LifeMed Alaska declined at 1637 due to weather. Medevac Alaska was the third company contacted, and its dispatch officer, unaware of previous declinations, forwarded the request to Security Aviation. At 1731, Security Aviation accepted the flight, and the flight was staffed with a nurse and paramedic.
Radar and Witness Accounts
FAA radar and ADS-B data show the airplane departed PANC and flew south at about 3,000 ft msl toward the Sterling Highway. It then descended to 2,200 ft msl while flying a right racetrack pattern before entering the valley toward Cooper Landing. The last data point at 1911:14 placed the airplane over the west end of Jean Lake at 2,100 ft msl, on a 127° course, at 122 kts groundspeed. Ground witnesses on the Sterling Highway near milepost 63 reported seeing the airplane's lights. One witness observed the airplane west of the mountains turn in a circle as it descended, then enter the valley, with wings rocking back and forth; he then heard an explosion and saw a large fire on the mountainside. Another witness saw the airplane flying low and explode on impact. Witnesses called 911 and observed the wreckage burning for a long time.
Weather Conditions
The closest weather reporting facility was Soldotna Airport (PASX), about 30 nautical miles west, with an 1856 observation: wind 250° at 3 knots, 10 sm visibility, broken clouds at 8,000 ft and 9,500 ft, temperature 36°F, dewpoint 36°F, altimeter 29.56 inHg. Sunset was at 1554. Witnesses reported dark night conditions and gusting winds. PAWD observations around the accident time showed light rain and mist, with visibility from 3 to 8 sm. Unofficial surface sites closer to the accident site reported gusty winds between 13 and 27 knots from the east to southeast, with precipitation. Satellite data depicted a low-pressure system over the Gulf of Alaska with an occluded front northward over the southern Kenai Peninsula. Graphical forecasts warned of MVFR to IFR conditions, surface winds >30 knots, LLWS, and moderate icing above 6,000 ft msl. The area forecast warned of occasional broken ceilings at 2,500 ft with light rain showers, visibilities 3-5 miles in light snow and mist. A WRF simulation indicated the airplane was in an area of rapidly transitioning updrafts and downdrafts of 1,500 fpm, with 30-40 knot winds and >50 knots near mountain tops.
Examination Findings
The wreckage was located on December 1, 2019, by Alaska State Troopers and the Alaska Mountain Rescue Group at an elevation of about 1,425 ft msl in steep, heavily tree-covered terrain near the southeast end of Jean Lake. The airplane was highly fragmented and burned, but all major components were accounted for. Multiple large trees around the wreckage were fractured, indicating an easterly heading prior to impact. Postaccident examination confirmed flight control continuity from cockpit to controls; broomstraw features at separation points indicated no fatigue. Aileron trim screw measurement roughly correlated to neutral trim. The left engine was impact-separated; the left propeller was separated at the crankshaft flange with blades showing bending opposite rotation, aft 90°, and curled forward 90°. The right engine remained attached with thermal and impact damage; the right propeller remained attached with blades exhibiting leading edge dents, chordwise scraping, chips, S-bending, and tip deformation.