Poor weather conditions contributed to an airplane crash last summer outside the Interior community of Cantwell that left three people dead, according to a probable cause report released Monday by the National Transportation Safety Board.
The plane crashed and caught fire on June 28, 2013, about 500 feet from the Parks Highway near Cantwell. Three people perished in the plane crash: Pilot Dale Hemman, 61, of Steilacoom, Washington, and passengers John Ellenberg, 74, of Greenville, South Carolina, and Laurie Buckner, 52, of Simpsonville, South Carolina.
The NTSB found that the plane had flown into instrument meteorological conditions -- weather that requires pilots to fly primarily using instruments, and in closer contact with air traffic control -- but that the pilot was flying operating under visual flight rules. That circumstance "resulted in an in-flight collision with mountainous terrain," the report states.
Weather at the time was reported as broken clouds about 250 to 300 feet above ground level, overcast clouds about 350 feet above ground level, with thin wispy fog hanging in the trees.
The probable cause report mirrors the findings of the NTSB's preliminary report released last summer.
Hemman was the director of operations at Let's Fly Alaska, a flightseeing company that organizes sightseeing squadrons in which visitors can fly their own airplanes across remote parts of Alaska and Canada.
On the day of the crash, Hemman was leading a group of 18 airplanes, flying from Fairbanks to the Southcentral community of Homer.
The planes were divided into two groups, with a group leader for each one. Hemman was flying ahead of both groups, as a separate leader for the entire tour, according to the NTSB.
Hemman departed about 10 minutes before the other two groups to make arrangements at their next destination and to check weather along the route, which took them through Windy Pass, Alaska Dispatch reported last summer.
Neither of the two group leaders heard from Hemman after departing Fairbanks, Alaska's NTSB office chief Clint Johnson told Alaska Dispatch.
As the other group leaders approached the mountain pass, one group leader reported that weather conditions began to deteriorate, with low clouds, haze and restricted visibility. A radio broadcast from another airplane in the area indicated that the mountain pass was not open due to poor weather. The group leader decided to land his group at nearby Healy River airport, and the second group leader followed suit.
A witness on the ground who happened to be a pilot reported that he saw Hemman's plane flying in and out of the clouds at an altitude of around 400 feet above ground level, according to the report.
The airplane's wreckage was discovered near the summit of the mountain pass in brush and tundra-covered terrain near where the second group leader turned around, according to the report. Johnson said last summer that the plane was about 500 feet from the road, near mile 195.5 of the highway that connects Fairbanks and Anchorage.
The twin-engine Beech Baron 95-B55 was severely fragmented, Johnson said at the time. Alaska State Troopers spokesperson Beth Ipsen told Alaska Dispatch that debris field from the plane's wreckage was 500 to 700 feet long.
Post-accident investigation revealed no mechanical malfunctions or anomalies, according to the report.