On 15 January 2023, Yeti Airlines Flight 691 crashed in Nepal, killing all 72 people onboard.
The ATR 72-500 took off from Kathmandu and crashed just before landing in the city of Pokhra.
It is one of Nepal’s worst aircraft accidents in the past three decades, and the deadliest incident involving an ATR 72 aircraft.
Overview of the airplane crash over Nepal
Yeti Airlines 691 departed from Kathmandu’s Tribhuvan International Airport on the morning of Sunday 15 January 2023 at approximately 10.33 am (Nepal Standard Time).
While on its final approach to Pokhara International Airport, the aircraft crashed onto the Seti Gandaki River bank.
Pilot Anup Joshi had stated that the mountains were clear, and that “visibility was good”. Mr Joshi also reported that there was no issue with the weather.
All 72 onboard were killed.
Authorities stopped searching for survivors and have now focused on determining what caused the incident.
How did Yeti Airlines Flight 691 crash?
The Nepalese Government have established a panel to investiate the cause of the crash. A preliminary investigation report published by the Nepalese Aircraft Accident Investigation Commission in February 2023 found that the cause was pilot error.
During the descent, one of the pilots selected the incorrect lever, feathering the propellors when he should have lowered the flaps. The aircraft stalled and then crashed.
According to K.B Limbu, aviation expert, propellors when going into feather result in no thrust in the engine. That means that no power was being produced.
It has been reported that the pilot, when approaching the airport, did not report anything untoward.
Ron Bartsch: Nepal terrain “terribly difficult to fly”
Professor Ron Bartsch, founder of Avlaw Aviation Consulting, suggested shortly after the crash occurred, that the tragedy may have been caused by Nepal’s strong winds.
Speaking to The Sun, Bartsch suggested that Nepal’s terrain is “terribly difficult to fly” because of the country’s winds and high altitude.
He also commented that the runways are some of the world’s “most challenging”.
Nepal’s thin atmosphere, coupled with a possible speed miscalculation by the pilot, could have caused the accident. Bartsch said that, usually, aircraft fly faster when they are travelling through thin air at higher altitudes.
This is because air density falls at such altitudes, lowering the engine’s performance.
At the same time, aircraft burn less fuel when flying so high.
Bartsch therefore suggested that the pilot may have misjudged the situation, thinking the plane was flying faster than it really was. This caused the engine to stall, and thus crash.
More details will become known about the Nepal airplane crash when the Commission releases their final report.