A Yeti Airlines plane crash that killed 72 was caused by the flight’s pilots mistakenly feathering the propellers, a government-appointed investigative report has found.
The feathering caused a loss of thrust, which then led to an aerodynamic stall.
The ATR 72 aircraft, operated by Yeti Airlines, crashed just before it was due to land in the tourist city of Pokhara on January 15, 2023. It was Nepal’s deadliest plane crash in 30 years.
Among the 72 victims of the flight were two infants, four crew and 15 foreign nationals. There were no survivors.
According to the report, the 72-hour history of both pilots did not indicate fatigue or health issues to be a factor in the fatal mistake. “Both pilots were reported to have eaten routine foods, went to bed, and rose at routine hours,” the report said.
The twin-engine aircraft was found to have been maintained properly, with no maintenance work overdue.
Furthermore, the report stated that the most probable cause of the accident had been determined to be the inadvertent movement of both condition levers to the feathered position in flight. This feathering of both propellers resulted in a loss of thrust, leading to an aerodynamic stall and eventual collision with terrain.
“Following the unintentional feathering of both engine propellers, the flight crew failed to identify the problem and take corrective actions despite the Crew Alerting Panel cautions,” the report said.
The report also identified human considerations such as high workload and stress and non-compliance with standard operating procedures as factors that had contributed to the accident.