NTSB Cites Inadequate Training In Fatal Crash
Commercial fixed-wing pilots who fly under Part 135 (commuter and on-demand) should get the same FAA-approved CFIT training as helicopter pilots, the NTSB said Tuesday, in its report on a fatal accident in 2016. Two commercial pilots and a passenger died when a Cessna 208B Grand Caravan operated by Hageland Aviation Services crashed into mountainous terrain near Togiak, Alaska. “This crash involved a well-equipped airplane with not one but two professional pilots on board,” said NTSB Chairman Robert Sumwalt. “But the many layers of protection against controlled flight into terrain failed to protect the pilots and their passenger.’’ The investigation found that while Hageland aircraft were equipped with a terrain avoidance warning system, pilots routinely turned off the aural and visual alerts while flying at altitudes below the TAWS alerting threshold, to avoid receiving nuisance alerts.
During the last four minutes of the flight, the airplane was flying at about 1,000 MSL, the NTSB said, with terrain clearances of about 500 to 700 feet. Shortly before the crash, the airplane climbed as it approached a mountain ridge, and likely entered IMC. The airplane struck terrain at about 2,300 feet MSL. Hageland flights operated under VFR were allowed to fly as low as 500 feet AGL, which was below the TAWS alerting threshold, the NTSB said. The TAWS system was equipped with a switch that enabled the pilot to manually inhibit all aural and visual caution and warning alerts. A simulation that used an estimated flightpath for the accident airplane showed that if the alerts were not inhibited, the TAWS would have provided continuous alerts for most of the flight. The investigation concluded that the TAWS alerts were likely inhibited for most, if not all, of the flight, eliminating a margin of safety.
Currently, only Part 135 helicopter operators are required to train their pilots using an FAA-approved CFIT avoidance training program, the NTSB said. While Hageland offered CFIT training based on guidance from the nonprofit Medallion Foundation, the investigation found the training was outdated and did not address specific CFIT risks faced by Hageland pilots while flying under VFR near Alaska’s mountainous terrain. The complete accident report will be available in several weeks. The executive summary, including the findings, probable cause and safety recommendations, is available online.