What aircraft was involved and where did it happen?

The accident on 2018-03-14 involved a Eurocopter EC135 P2+, registration VH-ZGA, operated by Heli-Aust Whitsundays, at 37 km north-north-west of Port Hedland Heliport, Western Australia.

What was the probable cause of the accident?

The accident was caused by the crew's failure to monitor flight instruments and maintain the standard circuit profile during a descent in a degraded visual environment, compounded by the lack of autopilot vertical navigation coupling.

Night Training Flight Ends in Fatal Helicopter Water Impact

A supervised night training flight involving an EC135 helicopter resulted in a fatal impact with the ocean near Port Hedland, driven by pilot disorientation and procedural deviations.

What happened

During a night positioning flight near Squireship, approximately 20 NM offshore from Port Hedland, an EC135 helicopter descended into the ocean. The flight was part of a third-line training session intended to induct a newly employed pilot into night operations. The pilot in command was being supervised by a company instructor.

While circling the bulk carrier, the crew operated in a degraded visual environment characterized by low celestial lighting and minimal coastal landmarks. Following a missed approach and a climb to 1,100 ft, the crew initiated a descent without utilizing the autopilot's vertical navigation mode, deviating from standard practices. During the downwind and base segments of the circuit, the aircraft experienced a rapid descent and decaying airspeed. The crew failed to monitor flight instruments effectively, and neither pilot reacted to the abnormal flight path until a radio altimeter alert triggered at 300 ft. Although the instructor attempted to reduce the descent rate, the aircraft struck the water with significant force. The cabin submerged and flooded immediately; the instructor managed to escape through a gap in the windscreen, but the pilot under supervision died in the cockpit.

The investigation

Because the EC135, registration VH-ZGA, was not equipped with a flight data recorder or cockpit voice recorder, the ATSB utilized GPS-based ADS-B data and interviews with the surviving pilot. The ADS-B analysis confirmed that the aircraft's vertical path and airspeed were abnormal during the period leading up to the impact. The investigation also examined the operator's training procedures, fatigue management systems, and the cockpit configuration of the aircraft.

Findings

The crew operated in a degraded visual cueing environment, which increased workload and the risk of spatial disorientation.
The decision to descend without coupling the autopilot's vertical navigation mode increased attentional demands and the risk of procedural deviation.
The pilots failed to monitor flight instruments, leading to an undetected descent below the standard circuit profile.
The aircraft's instrumentation was configured for single-pilot IFR operations, which hindered the instructor's ability to monitor the flight path and intervene effectively during training.
The pilot under supervision had transitioned to a new aircraft type and environment without sufficient night-flying preparation or consolidation.
The operator's fatigue management system was flawed, relying on a sleep log that was susceptible to inaccurate entries and contained coding errors.
The pilot under supervision lacked recent underwater escape training (HUET) recency.
The operator's approach procedures lacked mandatory go-around policies and stabilized approach criteria.