ATSB investigators suspect a pilot had a medical episode that led to the fatal crash of a Cessna 150 in WA earlier this year, according to an investigation report released this week.
C150M VH-WWU was on a ferry flight from Geraldton to Shark Bay in March when the aircraft entered a left-hand spiral dive and crashed 21 nm north-west of Northampton. The pilot, the only person on board, died in the crash.
It was the pilots second flight of the day, having ferried another C150 from Shark Bay to a maintenance hangar in Geraldton earlier that morning, swapping the aircraft for WWU.
Investigators found that the pilot had a history of medical issues and witnesses reported them feeling ill in the days leading up to the flight. The ATSB believes the pilot was incapacitated at the time the aircraft entered the spiral dive and was unable to regain control.
“Wreckage examination found no evidence of any in-flight failure of the airframe or flight controls, and the engine was producing power throughout the descent,” ATSB Chief Commissioner Angus Mitchell said.
“Based on the pilot’s significant aviation experience and medical history, and the established sequence of events, it was determined the pilot likely experienced an incapacitating medical event resulting in a deviation off track and the uncorrected spiral dive.”
Data recovered from a Garmin 296 on board WWU showed that the aircraft deviated to the right of its path, with the pilot attempting to regain the track with two shallow left turns. It was the second turn that steepened into the spiral dive.
Consultations with medical professionals led investigators to consider medical events that could have caused the incapacitation, including cardiovascular conditions and acute gastroenteritis.
"On the day of the accident while at the maintenance facility in Geraldton, aircraft maintainers noted that the pilot’s skin appeared pale, the pilot had yellow, sunken eyes and appeared to have lost a significant amount of weight," the ATSB report states.
"They recalled the pilot stating they had gastroenteritis, had not been eating and had lost 4 kg of weight in the preceding days."
“While it is very likely the pilot experienced an incapacitation event, the evidence available did not allow the exact nature of the incapacitation to be determined,” Mitchell said.
The ATSB is encouraging pilots to use the IMSAFE checklist to prioritise pilot fitness to fly and protect the safety of the people on board the aircraft.
The full investigation report is on the ATSB website.