Toxic gas slowly filling the cabin of a seaplane flying over a river in Sydney s north was the likely cause of a tragic crash that killed six people, a final report into the incident has found. Gareth Morgan was carrying five passengers on the Sydney Seaplanes DHC-2 Beaver when it took off at Cottage Point and crashed in Jerusalem Bay, in the Ku-ring-gai National Park, on New Year s Eve in 2017. Elevated levels of carbon monoxide seeping into the plane left him confused, disoriented and unable to safely fly the aircraft, the Australian Transport Safety Bureau has ruled. On board the flight bound for Rose Bay was the chief executive of catering giant Compass, Richard Cousins, his sons Edward and William, fiancee Emma Bowden and her 11-year-old daughter Heather.