The Australian Transport Safety Bureau (ATSB) has issued a recommendation to the US Federal Aviation Administration (FAA) to amend fixed-wing aircraft certification to reduce the chances of post-impact fire following the fatal crash of a crop sprayer in 2021.
An agricultural pilot was killed near Moree, NSW, in 2021 when Air Tractor AT-400 VH-ACQ stalled in a procedure turn, according to an ATSB investigation report released late last week.
The pilot had completed five spray runs from the eleventh load that day when the aircraft crashed whilst turning for another run. The ensuing fire destroyed the aircraft and fatally injured the pilot.
ATSB investigators determined that the aircraft was too close to the start of the next spray run, which probably prompted the pilot to steepen the turn.
“This almost certainly resulted in an aerodynamic stall at a height too low to recover before colliding with the ground," said ATSB Director Transport Safety Dr Stuart Godley.
"Mishandling the turn was probably a result of the combined effects of the pilot experiencing high workload and fatigue due to long flight and duty times, inexperience, the complexity of the task and the weather conditions."
The pilot had already radioed the company operations manager expressing concern about the weather and the potential for the chemical to drift onto a neighbouring property. About five minutes later, the pilot returned to the target block, and conducted two "smoker" runs to assess the drift, followed by five parallel spray runs.
At the end of the fifth spray run, the aircraft entered a right procedure turn, resulting in the crash.
Investigators found that the pilot was almost certainly wearing a helmet and four-point harness, which increased their chances of survival. However, the aircraft’s fuel tanks ruptured during the accident, resulting in a fire that killed the pilot.
“The aircraft was not fitted with a crash-resistant fuel system, nor was it required to be,” Godley said.
“As such, post-impact fire presents a significant risk of fire-related injuries and fatalities to occupants of general aviation aeroplanes.
“As such, the ATSB has issued a formal Safety Recommendation to the US Federal Aviation Administration to take action to address certification requirements for crash-resistant fuel systems for fixed wing aircraft to reduce the risk of post-impact fire.”
ATSB data shows that a person is killed in a post-impact aircraft fire in Australia once every two years.
The FAA initially responded saying they were "forming a cross-organisational team to review the topic of post-crash fires and identify potential risk mitigations."
However, as the FAA gave no timeframe or commitment to new safety standards, the ATSB issued a formal recommendation for change.
The full accident investigation report is on the ATSB website.