Cessna U206 with door unable to be opened more than 8 cm when flap is extended. Source: TSB Canada, annotated by ATSB
The collision with water of a Cessna 206 near Fraser Island, Queensland highlights known issues with evacuating from the aircraft where extended flap obstructs the opening of its rear clamshell cargo doors.
The Australian Transport Safety Bureau (ATSB) investigation into the 29 January 2020 accident has identified two safety issues associated with the Cessna 206 with a cargo door that can lead to fatal consequences in the event of a ditching. As a consequence, the ATSB has issued safety recommendations to the manufacturer and regulatory authorities in Australia and the United States to address the issues.
“The Cessna 206 procedure for ditching and forced landing states that the flaps are to be extended to 40°,” said ATSB Director Transport Safety Stuart Macleod.
“While that permits the aircraft to land at a slower speed, it also significantly restricts emergency egress via the cargo door. However, there is no warning about that aspect in the pilot’s operating handbook emergency procedures for a ditching or forced landing.”
The ATSB also found that the Cessna 206 with the cargo door does not meet the aircraft certification basis for the design of cabin exits, due to the complexity associated with opening the cargo door if it is blocked by the flaps.
“This significantly hampers emergency egress and has previously resulted in fatalities.”
To address these issues the ATSB has issued safety recommendations to Textron Aviation (Cessna’s parent company) and the US Federal Aviation Administration and Australia’s Civil Aviation Safety Authority.
“The ATSB is recommending that Textron amend the procedure for ditching and forced landing in the pilot operating handbook for the Cessna 206 to ensure pilots are aware that extending the flaps beyond 10° will significantly restrict emergency egress via the cargo door,” said Mr Macleod.
“Separately, the ATSB also recommends that the Federal Aviation Administration and Civil Aviation Safety Authority take safety action to address the certification basis for the design of the cargo door in the Cessna 206.”
The accident aircraft, a Cessna U206G operated by Air Fraser Island, was being used to conduct emergency procedures training at a beach landing area on Fraser Island with two pilots (a training pilot and trainee pilot who had just commenced flying with the operator) on board. During a simulated failure of the left main wheel during landing, a section of the nose landing gear attachment failed just after landing, resulting in the rudder becoming jammed in the full‑left position.
The aircraft veered to the left, toward the sea, and the training pilot elected to conduct a go-around. With the rudder jammed in the full‑left position, the pilot had to apply full opposite aileron to maintain control.
Subsequently, fuel starvation, due to either the uncoordinated ‘crossed controls’ flight (using opposite aileron to counter the jammed rudder) or damage associated with the nose gear failure, led to the engine losing power at a height too low for recovery, and the aircraft impacted the water.
After hitting the water, the aircraft remained upright, and the cabin quickly began to fill with water.
With the trainee unable to open the pilot door, the training pilot moved to the back of the aircraft and attempted to open the forward door of the ‘clamshell’ rear double cargo doors. In order to escape the training pilot had to force the door open by kicking it, as it was partially blocked by the partially-extended flap (set at 20°).
The pilot managed to leave the cabin through the cargo door, while the trainee exited through the pilot door window. Both swam to shore.
The aircraft, without the engine, washed up on the beach the morning after the accident.
“Cessna 206 pilots should be aware that lowering the flaps will block the cargo door exit and significantly increase the difficulty of opening the door,” said Mr Macleod.
“In the event that a ditching is required, pilots should consider not extending the flaps.
“Additionally, all passenger pre-flight briefings should also include a practical demonstration of how to open a partially-obstructed cargo door.”
Mr Macleod noted that research by the Transport Safety Board of Canada found that in the 20 years leading up to 2009, 70 per cent of fatalities where an aircraft collided with water were caused by drowning.
“That statistic reflects the inherently disorienting nature of underwater exit from an often-inverted aircraft,” he said.Last update 08 July 2021