Inquest into the deaths of Emma Bowden, Heather Bowden-Page, Edward Cousins, Richard Cousins, William Cousins & Gareth

Unknown·Multiple blunt force injuries and immersion secondary to seaplane crash caused by pilot impairment from carbon monoxide exposure

On 31 December 2017, a de Havilland DHC-2 Beaver seaplane crashed into Jerusalem Bay, Sydney, killing all six occupants. The coroner found the crash was caused by pilot impairment due to carbon monoxide (CO) exposure. Pre-existing cracks in the aircraft's exhaust manifold allowed CO to enter the cabin through breaches in the firewall (three missing AN3-3A bolts in magneto access panels and a misoriented panel). The pilot had a carboxyhaemoglobin level of 11%, which impaired his cognitive function and aircraft operation. Maintenance contractor Airag Aviation Services used non-standard bolts and parts without approval or testing, and failed to establish written safety policies or adequately supervise staff. A critical investigative delay occurred—toxicology was not tested for CO initially, only in March 2020 nearly two years after the crash. The coroner made eight recommendations to Airag, NSW Health Pathology, CASA, and the ATSB addressing maintenance procedures, pathology protocols, and aviation safety regulations.