Coulson Aviation and the relevant Western Australian Government Departments had not published a minimum retardant drop height in their respective operating procedures for large airtankers. Consequently, the co-pilot (pilot monitoring), who did not believe there was a minimum drop height, did not alert the aircraft captain (pilot flying) to a drop height deviation prior to the collision.
The amendment to the Western Australian Aerial Fire Suppression Procedures to incorporate drop heights should adequately address this safety issue.
In November 2023, the Department of Fire and Emergency Services, and the Department of Biodiversity, Conservation and Attractions released the Western Australian Aerial Fire Suppression Procedures 2023–2024. The draft version of this document was reviewed by their contracted operators and included a chapter for Large Air Tanker (LAT) Operating Procedures. The document included drop heights for the aircraft types employed, which included a LAT drop height of 200 ft.
