How carbon monoxide played fatal role in Sydney seaplane tragedy

An inquest into the deaths of a British family and Canadian pilot, who died when the seaplane they were travelling in nosedived on New Year’s Eve, has heard how elevated levels of carbon monoxide may have played a role in the tragic accident.

An inquest into the deaths of a British family and Canadian pilot, who died when a seaplane they were travelling in plummeted into the Hawkesbury River on New Year’s Eve 2017, has heard how carbon monoxide may have caused the tragic accident.

Richard Cousins, 58, his sons Edward, 23, and William, 25, as well as his fiance Emma Bowden, 48, and her 11-year-old daughter Heather, had travelled to Australia from Great Britain in 2017.

Mr Cousins, the chief executive of catering giant Compass, and his two adult sons had previously attended the MCG for the Ashes’ Boxing Day test and had tickets for the final test at the SCG.

But the Cousins’ and Bowdens’ holiday reached a tragic end when they embarked on a seaplane flight from Cottage Point, in Sydney’s northern most reaches, to Rose Bay.

The plane, flown by experienced pilot Gareth Morgan, veered off course and nosedived into Jerusalem Bay shortly after taking off.

Richard Cousins and his fiancee Emma Bowden.

Emma Bowden and her daughter Heather. Picture: Facebook.

An investigation by the Australian Transport Safety Bureau (ATSB) previously concluded the plane’s passengers and pilots all had higher than normal levels of carboxyhaemoglobin in their blood.

“This was almost certainly due to elevated levels of carbon monoxide in the aircraft cabin,” the ASTB’s report reads.

Pilot Gareth Morgan, who died along with his passengers.

Wreckage of the seaplane after is crashed into Jerusalem Bay. Picture: Richard Dobson.

“(The) wreckage examination established that several pre-existing cracks in the exhaust collector ring, very likely released exhaust gas into the engine/accessory bay, which then very likely entered the cabin through holes in the main firewall where three bolts were missing from the magneto access panels,” the report states.

Professor Con Doolan and professor Steven Armfield told the inquest on Tuesday how they believed carbon monoxide might have entered the pilot’s cabin.

Professor Armfield said there must have been some pathway from the exhaust gases into the cabin and the question was what that pathway was.

Referencing the ASTB’s report, Professor Doolan told the inquest given the carbon monoxide concentration in the cabin, the most obvious pathway for the gas was through the missing bolt holes and into the firewall — the part of an aircraft which separates the engine.

“It seems to be the most obvious pathway, that’s not to say there couldn’t be another one,” he said.

The inquest continues.