An interim report into a deadly seaplane crash off Rottnest Island has revealed a critical stall warning horn may have been intentionally turned off prior to the accident. The Australian Transport Safety Bureau (ATSB) released its preliminary findings, which will now lead to a deeper investigation into the aircraft's crashworthiness and the pilot's decision-making.
What the Interim Report Found
The tragic incident occurred in January 2025, claiming the lives of 34-year-old pilot James Wong and two tourists, Torben Poulsen and Danielle Grundbacher-Mosching. The group was aboard a Cessna 208 Caravan floatplane, operated by Swan River Seaplanes, attempting a take-off from Thomson Bay.
According to ATSB Chief Commissioner Angus Mitchell, the pilot had assessed the conditions twice that afternoon. Facing strong winds in the usual take-off area, the pilot opted for an alternative, easterly path closer to shore, believing the swell to be less severe.
The aircraft accelerated in a strong crosswind and light tailwind but encountered sea swell and chop as it passed Phillip Rock. This caused the seaplane to strike the water at a speed of approximately 57 knots.
The coroner confirmed the pilot and a front-seat passenger died from drowning. The second passenger also drowned, but this was a consequence of a head injury sustained in the impact.
Focus on the Stall Warning System
A significant finding in the report centres on the aircraft's stall warning system. The ATSB noted that pilots of similar Caravan aircraft have previously reported false alarms from this system during water take-offs, which has led to the practice of disconnecting it.
Evidence supporting this emerged from passenger video footage. No stall warning horn was audible in the cabin audio as the plane approached Phillip Rock and became airborne. After the accident, investigators found the stall warning circuit breaker in the 'out' position, meaning power to the horn was cut.
Ongoing Investigation and Future Focus
The ATSB has stated that its final report is not expected until the second half of 2026. The ongoing investigation will expand into several critical areas:
- Crashworthiness: Examining the design of the Cessna Caravan and its performance in an impact with water.
- Emergency Procedures: Assessing the suitability of the manufacturer and operator's emergency equipment and protocols for water immersion accidents.
- Operator Oversight: Scrutinising Swan River Seaplanes' risk assessment procedures for Thomson Bay operations, their identification of suitable take-off areas, and overall operational oversight.
While the pilot's actions and decision to change course remain a key part of the inquiry, Mr Mitchell emphasised the investigation is equally focused on the systemic safety controls and procedures in place at the operating company.
