What happened
On 23 January 2020, a Lockheed Martin C-130, operating as ‘Bomber 134’ (B134), departed Richmond Royal Australian Air Force Base, New South Wales, for a firefighting mission. After determining that conditions at Adaminaby were unsuitable for a fire-retardant drop, the crew accepted an alternative tasking at the Good Good fire near Peak View.
During a left turn following a partial drop, the aircraft's climb performance ceased. The aircraft's pitch and wing attitude shifted, and it was observed in a left wing-down position at low altitude before striking the ground. The accident resulted in 3 fatalities and the destruction of the aircraft.
The investigation
The investigation examined the aircraft's mechanical state and the environmental conditions at the time of the crash. While the impact damage and subsequent fire prevented a full systems verification, investigators found no known defects affecting serviceability, and all engines were producing power at impact. The crew was found to be appropriately qualified, and there was no evidence of fatigue or medical incapacitation contributing to the event.
Meteorological data confirmed that the area was experiencing hazardous weather, including mountain wave activity, severe turbulence, and strong winds. Analysis of ADS-B data suggested wind speeds between 20-40 knots from the north-west. The investigation also noted that the aircraft lacked a windshear detection system and that the cockpit voice recorder failed to capture the flight.
Findings
- The aircraft likely experienced an aerodynamic stall caused by low-level windshear and an increased tailwind component during the turn.
- The crew was likely unaware that other aircraft had already ceased operations in the area due to the dangerous weather.
- Safety management processes at Coulson Aviation were insufficient for managing the risks of large air tanker operations, specifically regarding the lack of operational risk assessments and a risk register.
- The New South $Wales$ Rural Fire Service lacked comprehensive policies for large air tanker supervision and procedures for managing task rejections.
Safety message
- Coulson Aviation should implement pre-flight risk assessments to provide objective criteria for accepting or rejecting flight tasks.
- Windshear recovery procedures should be integrated into flight manuals and simulator training.
- The New South Wales Rural Fire Service should establish clear procedures for aerial supervision and the communication of task rejections to all pilots in the area.