Investigations into the Yeti Airlines crash in Nepal that killed 71 people last month indicate the strong possibility of a startling error by one of the pilots. Five Indians were also killed in the crash.
The Yeti Airlines flight 691, which took off from Kathmandu's Tribhuvan International Airport on January 15, crashed on the Seti River gorge between the old airport and the new airport in the resort city of Pokhara.
The preliminary crash report reveals that instead of using the flaps lever in the cockpit to configure the aircraft for landing, one of the pilots operated levers which "feathered" the engines - bringing engine power to zero.
Less than a minute later, the ATR-72 aircraft crashed and stalled.
The plane lost thrust and fell after the propellers of both engines went into the feathered position. It is rare for the propellers of both engines to come to a feathered position, the report notes.
"When Air Traffic Controller (ATC) gave the clearance for landing..., the Pilot Flying (PF) mentioned twice that there was no power coming from the engines," the report says.
The engines of the aircraft were fully functional at the time of the accident.
Flaps are rectangular panels on the wings that are extended to increase their surface area and give the aircraft more lift at slow speed during landing and taking off. If the flaps aren't extended before landing, the plane loses the lift and crashes. Bringing the engine to idle speed with no flaps extended during landing is a gravely unstable configuration.
The flight was being operated by two Captains - one was in the process of being familiarised for operations into Pokhara. The co-pilot was an instructor pilot.
The pilot landing the aircraft for the landing is believed to have been Anju Khatiwada, one of six women pilots in the airline. Her husband, Dipak Pokhrel, flew for the same airline and was killed in a crash in 2006.
The crash was captured live by some Indian passengers who were also killed.
There were 72 people, including four crew members, on the flight. Rescuers have managed to find only 71 bodies, with the missing passenger presumed dead.
According to the preliminary report, the flight crew had made two flights between Kathmandu and Pokhara earlier in the morning. The flight that crashed was the third in a row by the same crew.
Nepal has one of the worst aviation safety records in the world.