2020 Coulson Aviation Lockheed EC-130 crash

Investigation

The ATSB investigation's final report detailing the occurrence, findings, and safety recommendations was released on 29 August 2022.

The accident site was located near Peak View, New South Wales, with the debris trail distributed linearly over around 180 m of terrain. The on-site examination found that the aircraft collided with a tree before colliding with the ground. An intense post-impact fuel-fed fire destroyed the aircraft. There was no evidence of pre-impact structural damage.

The aircraft's cockpit voice recorder did not record the accident flight, when the data was downloaded, the ATSB found thirty-one minutes of audio data from a flight in the previous year. It was likely that an inertial switch in the unit was activated during a previous landing of the aircraft and consequently disconnected power to the device.

Cause

The ATSB's investigation identified the following to be factors contributing to the aircraft's collision:

Hazardous weather conditions, including strong gusting winds and mountain wave activity, produced turbulence which was also exacerbated by the fire and local terrain.

The NSW RFS continued with the exercise despite no other aircraft continuing to operate due to the weather conditions. In addition, the NSW RFS relied on the pilot-in-command to assess the viability of the task without providing them with all the available information to make an informed decision on flight safety.

Once the aircraft's crew concluded that a fire retardant drop was too unsafe at the Adaminaby Fire-ground due to poor weather conditions, they proceeded to the Good Good Fire-ground which was subject to similar weather conditions, in line with their company's policy.

Following the partial retardant drop and left turn, the aircraft was very likely subjected to low-level wind shear and an increased tailwind, which would have decreased the aircraft's climb performance. While at a low height and airspeed, it was likely the aircraft stalled, leading to a collision with terrain.

The ATSB's investigation also identified the following to be factors that increased risk levels associated with the flight:

The aircraft's crew were, very likely, unaware that the observation aircraft had ceased operations in the area, due to the hazardous environmental conditions.

Due to the limited reaction time available to the crew, the remainder of the fire-retardant load was not dumped prior to the aircraft stalling.

Findings and recommendations

The ATSB highlighted a number of safety issues and issued a number of recommendations in its final report. The ATSB found that:

The NSW RFS did not have a policy or procedures in place to manage when pilots rejects a task, nor to communicate this information internally, or to other pilots that are working in the same area and recommended that the NSW RFS establish such policy.

The NSW RFS had limited policies and procedures outlining the aerial supervision requirements for large air tankers and no procedures for deployment without aerial supervision and recommended the NSW RFS establish such policy.

The NSW RFS procedures allowed aircraft operators to determine when their pilots were initial attack capable. However, they intended for the pilot in command to be certified under the US Forest Service certification process.

Coulson Aviation's risk management processes did not adequately manage the risks associated with large air tanker operations. There were no operational risk assessments conducted or a risk register maintained. Further, safety incident reports were mainly for maintenance issues, or operational risks, and were less likely to be considered or monitored. Overall, this limited their ability to identify and implement policy to reduce the risks associated with their aerial firefighting operations.

Coulson Aviation did not include a wind shear recovery procedure or scenario in their C-130 Flight Manual and annual simulator training to ensure that crews consistently and correctly responded to a wind shear encounter with minimal delay. Coulson Aviation has since amended its manuals and simulator training to include wind shear recovery procedures.

Coulson Aviation fleet of C-130 aircraft were not fitted with a wind shear detection system, which increased the risk of a wind shear encounter and/or delayed response to a wind shear encounter during low-level operations. Coulson Aviation responded by stating that "unless evidence that Predictive wind shear Detection equipment would provide detection in an extremely dry atmosphere (found around fires)... any discussion regarding Predictive wind shear Detection equipment for these types of operations, is irrelevant." The ATSB acknowledged that predictive wind shear warning systems may have a reduced effectiveness in drier environments. However, they also stated that on the day of the accident, the wind shear system on the B137 activated when operating in similar environmental conditions to what was very likely experienced by the N134CG crew. The ATSB recommended that Coulson Aviation further consider the fitment of a wind shear detection system to their C-130 aircraft to minimise the time taken for crews to recognise and respond to an encounter particularly when operating at low-level and low speed.

Coulson Aviation did not provide a pre-flight risk assessment for their fire-fighting large air tanker crews that would have provided predefined criteria to ensure consistent and objective decision-making with accepting or rejecting tasks, including factors relating to crew, environment, aircraft and external pressures. The ATSB recommended that Coulson Aviation incorporate foreseeable external factors into their pre-flight assessment tool to ensure the overall risk profile of a tasking can be consistently assessed by crews.