Nepal’s investigation committee revealed on Monday that a faulty engine might have been the cause of the country’s deadliest plane crash in over three decades, which left 72 passengers and crew members dead.
The committee made the revelation after analyzing data from the flight recorder and cockpit voice recorder of the Yeti Airlines ATR-72 aircraft that crashed in Pokhara, Nepal, on Jan. 15.
“In ATR-72 aircraft feather means to stay inclined to 90 degrees in spite of being in a certain degree as turned by the pilots,” the committee stated in its report, according to ANI News.
“In order to increase the speed, the pilot has to incline the propeller blade using the liver [sic] that is in the cockpit. With the propeller blade standing at 90 degrees, the plane would lose aerodynamic movement,” it added.
The twin-engine ATR-72 aircraft was flying from the capital of Kathmandu to Pokhara when it plummeted into a gorge as it approached the airport. The crash site is about 1.6 kilometers (1 mile) from the runway at an elevation of about 820 meters (2,690 feet).
Search teams found 71 bodies as of Jan. 18, and the search for the final victim continues. Police said it has been difficult to identify bodies owing to the condition of the remains.
Two Americans and two permanent residents living in the United States were among those killed in the crash, according to the U.S. Department of State.
Prime Minister Pushpa Kamal Dahal Prachanda has urged hospital authorities to expedite the remaining autopsies of some victims so their bodies can be handed over to their families.
Jagannath Niroula, a spokesperson for Nepal’s Civil Aviation Authority, said on Jan. 19 that Pokhara International Airport’s instrument landing system will not be working until Feb. 26—56 days after the airport began operations on Jan. 1.
An instrument landing system helps airplanes fly safely when the pilot is unable to maintain visual contact with surrounding obstacles and the ground, mainly owing to weather conditions or at nighttime. Pilots can also fly by sight rather than relying on instruments.
Pilots say mountainous Nepal, where in-flight visibility problems are common, can be a difficult place to fly, but conditions at the time of the crash were good, with low winds and temperatures well above freezing.
Amit Singh, an experienced pilot and founder of India’s Safety Matters Foundation, said the lack of an instrument landing system or navigational aids could be a “contributory cause” of the crash and pointed to a “notoriously bad air safety culture in Nepal.”
“Flying in Nepal becomes challenging if you don’t have navigational aids and puts an extra workload on the pilot whenever they experience problems during a flight,” Singh said. “Lack of an instrument landing system only reaffirms that Nepal’s air safety culture is not adequate.”
The crash is Nepal’s deadliest since 1992, when a Pakistan International Airlines plane plowed into a hill as it tried to land in Kathmandu, killing all 167 people on board. There have been 42 fatal plane crashes in Nepal since 1946, according to the Safety Matters Foundation.
A 2019 safety report from Nepal’s Civil Aviation Authority said the country’s “hostile topography” and “diverse weather patterns” were the biggest dangers to flights in the country.
The European Union has banned airlines from Nepal from flying to the 27-nation bloc since 2013, citing weak safety standards. In 2017, the International Civil Aviation Organization cited improvements in Nepal’s aviation sector, but the EU continues to demand administrative reforms.
The Associated Press contributed to this report.