yesEtti Airways Flight 691 crashed on Sunday, 27 minutes after taking off from Kathmandu, before landing in the Nepalese tourist city of Pokhara, the gateway to a popular Himalayan hiking region.
At least 69 of the 72 people on board have been confirmed dead.
The pilot said Nepal could be a challenging place to fly, but conditions at the time of the crash were good, with light winds, clear skies and temperatures well above freezing. So what caused the ATR 72 to crash?
Did the plane stall?
A dramatic video captured on the ground with a smartphone showed the final moments before the plane crashed into a canyon about 1.6 kilometers (one mile) from the newly opened Pokhara International Airport. Amit Singh, founder and experienced pilot of India’s Safety Matters Foundation, said the plane’s nose was visibly high before the left wing suddenly drooped and the plane fell out of view of the video, indicating a possible stall .
“If you look at the trajectory of the plane, it’s nose up, and nose up is associated with a drop in speed,” he told the Associated Press. “When they have a stall, it’s usually one wing down, and the wing basically So, as the airflow decreases, there isn’t enough lift to keep the plane in flight, the wings droop and the plane plummets.”
Aviation safety expert and founder of Australia’s Avlaw Aviation Consulting, Professor Ron Bartsch, told Sydney’s Channel 9 he also believed the plane appeared to have stalled. Its proximity to the ground may have made pilots think they were going faster than they really were, he said.
“I think the plane has gone into an aerodynamic stall,” he said after reviewing the video before the crash. “Probably pilot error.”
Yeti Airlines spokeswoman Pemba Sherpa said the cause of the crash was under investigation.
Questions about the ATR-72 aircraft
The ATR-72 was introduced in the late 1980s as a French-Italian joint venture, and while it has had several fatal accidents over the years, several of them due to icing issues, it generally has a “very good record,” Bartsch said .
Searchers recovered a flight data recorder and a cockpit voice recorder from the crash site on Monday, but investigators cannot determine what happened until they are carefully analyzed.
“The human element is going to be one factor that investigators are going to look at to see if there’s been proper training,” Bartsch said. “But usually airplanes don’t fall out of the sky, especially modern ones.”
Singh said there may have been some sort of technical glitch in the plane’s instruments that was giving the pilot incorrect data, but even so, recovery from the stall was possible.
“Pilots should be trained to deal with technical failures,” he said.
Singh noted that despite “challenging airports and conditions”, Nepal’s aviation industry has a poor record on safety and training. Although it has been improving, he noted that its aircraft are banned from flying into European airspace.
A pilot who regularly flies the ATR-72-500 from India to Nepal said the area’s terrain, with its peaks and narrow valleys, increases the risk of accidents and sometimes requires pilots to fly by sight rather than by instruments.
The pilot, who works for a private Indian airline and did not want to be named due to company policy, called the ATR-72-500 a “ruthless aircraft” if the pilot is not highly skilled and not familiar with the terrain and wind speeds in the area.
ATR said on Twitter on Sunday that its experts had “full support for the investigation and clients” and that its “first thoughts are with all individuals affected by this.”
The company did not immediately respond to a request for further comment.
Concerns over Pokhara’s new airport
Nepal, home to eight of the world’s 14 tallest mountains, has a history of air disasters. There have been 42 fatal air crashes in Nepal since 1946, according to the Safety Matters Foundation.
According to a 2019 safety report by the Nepal Civil Aviation Authority, the country’s “harsh terrain” and “various weather patterns” were major challenges and also led to “numerous incidents” of small aircraft. The majority of such accidents occurred at airports with short takeoff and landing runways and were due to pilot error, the report said.
Pokhara’s airport, at an altitude of about 820 meters (2,700 ft), is a popular tourist destination and the gateway to the Annapurna mountain range.
Before the airport opened two weeks ago, some expressed concern that bird populations in the area – thanks to habitat provided by two rivers and a landfill near the airport – could make it more dangerous.
When the airport was officially opened, the mayor said work was done to mitigate the impact of the landfill, but it was unclear exactly what measures had been taken, according to local media reports.
If the plane experiences a bird strike on landing, it could prompt the pilot to stop the approach and go around again, which could also lead to a stall, Singh said.
“High thrust settings can cause a stall,” he said. “A go-around is most often mishandled by the crew…so the question is, how do the pilots cope with failure?”
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Associated Press Writer Sheikh Saaliq in New Delhi contributed to this report.
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