Narrative
On May 1, 2017, at about 1350 Alaska daylight time, a Cessna 208B airplane, registration N803TH, sustained substantial damage after impacting steep, mountainous terrain near Chignik Lake, Alaska. The airline transport pilot was fatally injured. The airplane was operated by Grant Aviation, Inc., as a Title 14 Code of Federal Regulations Part 135 non-scheduled mail contract flight. Instrument meteorological conditions existed at the accident site. Company flight following procedures were in effect for the visual flight rules flight, which had departed Port Heiden Airport at 1325, destined for Perryville Airport.
The pilot reported for duty at about 0800 that morning and was scheduled for a six-segment route. The accident occurred during the second segment. The first segment departed at 1215 and arrived at Port Heiden at 1313 with one passenger, who reported that the pilot flew lower than usual due to low clouds and flew through clouds. The airplane departed Port Heiden at 1325. The destination was about 80 miles south in a remote coastal area without official weather reporting or instrument approaches. The route crossed the Aleutian Peninsula with mountainous terrain elevations between 2,900 and 4,600 ft. No radar coverage or tracking equipment was available for this segment.
At 1353, the United States Coast Guard received a 406-MHz emergency locator transmitter signal from the accident airplane. The wreckage was located at 1730 about 24 miles northeast of Perryville Airport on a steep, snow-covered mountain. A rescue crewman determined that the pilot, inside the cockpit and strapped in his seat, had sustained fatal injuries.
Aircraft Information
The accident airplane, a 1992 Cessna 208B, had accumulated 17,990.7 total flight hours. It was powered by a Pratt & Whitney PT6A-114A engine rated at 675 shaft horsepower, with 13,120.1 hours total time, 2,882.3 hours since last overhaul. The propeller was a McCauley model 3GF34C703-B. The airplane was equipped for instrument flight and flight into icing conditions, and certified for single-pilot operation. It had a Garmin GNS 530 navigation system with integrated class B terrain awareness and warning system (TAWS) with visual and aural terrain alerts. A TAWS inhibit switch and light were included. The Garmin GNS 530 does not retain memory. The airplane was not equipped with ADS-B, flight tracking, flight data recorder, or cockpit voice recorder.
The aircraft logbook indicated a recurring chip detector light issue, with illumination on three occasions in February. Small slivers of fuzz material were found on the accessories gearbox magnetic chip detector. An oil sample analysis dated March 31, 2017, reported trace metallic elements consistent with alloy steel flakes similar to AMS6260 or AMS6265, used for engine gears. The pilot's flight log for the accident flight showed a load of 1,322 lbs of mail, takeoff weight of 8,100 lbs, and center of gravity of 200.5 inches.
Personnel Information
The pilot, age 54, held an airline transport pilot certificate with multi-engine land rating and commercial privileges for single-engine land, sea, and glider. He also held a flight instructor certificate. Company records showed 4,989 hours total flight experience, with over 904 hours in Cessna 208B airplanes. His most recent FAA second-class medical certificate was issued March 13, 2017, with a limitation to wear corrective lenses. Personal logbooks were not found.
The pilot completed initial company training and was assigned as pilot-in-command on the Cessna 207 in October 2014, on the Gipps Aero GA-8 in May 2015, and on the Cessna 208B in March 2016. His most recent proficiency check in the Cessna 208B was on April 9, 2017, including an instrument proficiency check and line check. He completed recurrent ground training including CFIT avoidance computer based training on November 19, 2016, and his most recent CFIT avoidance simulator training on January 31, 2016. He had accumulated 87.6 flight hours in the previous month, with 73.5 in the previous two weeks while based at King Salmon. He had no flights scheduled the day before the accident and had flown the accident route on 9 of the previous 10 days.
Meteorological Information
At the time of the accident, an AIRMET valid for the accident site forecast mountain obscuration due to clouds and precipitation. The area forecast issued at 1214 predicted scattered clouds at 2,000 ft agl and broken ceilings at 2,000 and 5,000 ft with tops to 10,000 ft, with isolated light rain showers and a freezing level at 1,500 ft. No turbulence or icing was forecast. The Alaska Aviation Weather Unit flying weather graphic indicated marginal VFR conditions for the route.
The nearest official weather reporting station, Chignik Airport, reported at 1239: variable wind 4 knots, 10 statute miles visibility, light rain, overcast at 1,700 ft, temperature 39°F, dewpoint 36°F, altimeter 29.51 inHg. Satellite data from GOES-15 at 1300 showed an overcast layer with likely mountain obscuration and cloud tops at 9,000 ft. FAA weather camera images from Chignik Lake (elevation 45 ft) revealed ceilings between 900 ft msl and 2,700 ft msl, with forward visibilities between 1.5 and 5 miles near the accident time, and mountain obscuration with likely rain showers.
The Perryville village agent stated that weather at the destination was generally good, with scattered clouds at 3,000 ft and 10 miles visibility. She could see north over the pass to Chignik, indicating a ceiling of at least 2,500 ft in the mountain pass. The accident pilot did not call her for a weather update. The dispatch agent recorded weather at Perryville as 10 miles visibility and overcast at 3,500 ft at 1021, with no further entries. She did not talk to the pilot during the flight. The company's General Operating Manual permitted personal observation or other competent persons if official weather was unavailable. The accident pilot did not request an official weather briefing.
Wreckage and Impact Information
On May 4, 2017, the Alaska State Troopers coordinated a recovery mission with the Alaska Mountain Rescue Group. The National Transportation Safety Board did not travel to the site due to remote location and hazardous terrain. The wreckage came to rest in deep snow at about 2,993 ft msl on the west face of a steep mountain in the Alaska Peninsula National Wildlife Refuge, about 500 ft from the ridge top. It was partially submerged on its left side with the nose under the snowpack. The fragmented wreckage was in an area 100 ft long by 35 ft wide, heading about 031° true. The right wing was separated about 40 ft forward, with a debris trail 30 ft behind the empennage. A narrow, 30-ft-long curved indentation in the snow about 65 ft behind the wreckage indicated a wing tip strike.
Postrecovery examination revealed structural damage including a large hole and buckling on the left fuselage, and inward compression in the forward fuselage and cockpit. The right wing separated inboard of attachment points with forward spar deformation; the left wing showed rearward overload tension signatures. Flight controls were continuous except for separated aileron cables with overload signatures. Deice boots had impact tears. Propeller blades exhibited trailing edge S-bending consistent with engine power at impact. The engine had moderate impact damage, and rotational rubbing marks indicated power at impact. Both magnetic chip detectors had fuzz material. The oil scavenge pumps showed scoring marks, and a small crushed plastic cap was found in the oil sump. No preaccident anomalies were noted that would have precluded normal operation.
Additional Information
The company had a CFIT Avoidance Manual defining CFIT and flat light conditions. Grant's policy allowed VFR flight in flat light if the pilot increased minimum altitude to 2,000 ft above the highest obstacle within 5 miles over mountainous terrain, or obtain IFR clearance. The CFIT avoidance program was voluntary. The pilot's most recent CFIT simulator training was 15 months before the accident, exceeding the program's annual requirement.
The company's Operational Control program included a flight risk assessment. The pilot and dispatch agent shared the decision to dispatch. The weather information used for the risk assessment was nearly 2 hours old and only provided landing area assessments. Both signed a risk assessment indicating a "2 yellow" value, acceptable. The assessment did not consider en route hazards. Company VFR minimums were 500 ft ceiling and 2 statute miles visibility regardless of terrain. Multiple company pilots described the route as hazardous due to terrain, rapidly changing weather, and lack of weather reporting. The route was acquired from another company about 3 years prior without a broad risk assessment.
The company's safety program was reactive, with a vacant safety officer position since February. The director of operations assumed those duties after the accident.
Autopsy attributed the pilot's death to multiple blunt force injuries. Toxicology testing was negative for drugs and alcohol.
Examination of the Garmin GNS 530W memory cards revealed a valid aviation database. The TAWS inhibit switch was in the neutral (off) position; the TAWS light filament did not show stretching, suggesting the light was not illuminated during impact.