Last Sunday a Yeti airlines flight from Kathmandu to the tourist town of Pokhara crashed when making its descent onto the runway.
Mobile phone footage of the crash shows the plane rolling onto its side sharply as it approached the runway before crashing into a nearby gorge.
In the following 24 hours search parties looked through the scattered parts of the plane. This included one portion of the aircraft that was on its side and still had its windows intact, as well as blue airline seats and other parts of the wreckage.
It is believed that none of the 72 passengers aboard the plane survived the crash, making it the country’s deadliest plane crash in 30 years.
Whilst authorities look through the black box and voice recorder, which was recovered by rescuers earlier this week, little is known about why the plane crashed. However, the area’s unforgiving conditions, changing weather and remote runways make aviation accidents in the region more common.
With these factors in mind, what could have caused the plane to crash?
Some aviation experts, including Amit Singh, an experienced pilot and founder of India’s Safety Matters Foundation, have suggested that the plane could have stalled mid-air.
This theory has come to light due to a video which has surfaced online of the plane's crash.
In the video, the nose of the plane is extremely high before the left wing rapidly drops and the plane falls behind the view of the camera.
Mr Singh explained to The Associated Press in an interview that when a plane stalls one wing tends to fall down. This reduces the airflow, which makes it harder for the plane to fly, causing it to nose dive and crash.
This explanation was also suggested by Professor Ron Bartsch, aviation safety expert and founder of Australia’s Avlaw Aviation Consulting, who explained that because of its proximity to the ground and the plane’s speed, the plane could have stalled.
Additionally, there are questions about the plane’s functionality.
The ATR-72 began flying in the late 1980s and although the model had been involved in some crashes, on the whole, it has a decent track record.
There is therefore the possibility that the Yeti Airlines crash was due to a technical failure. This could have provided the pilots with poor data, causing the plane to crash when it came to land.
Although this is a plausible theory, footage streamed via Facebook live by four friends from India suggested that when the plane came in to land all was calm.
The video then takes a more dramatic turn when the plane appears to veer off with a loud roar, before viewers hear the sound of it crashing.
The video suggests that no staff or passengers were aware that the plane was in any sort of danger before landing.
Additionally, recordings of the pilot asking to change the runway during descent have also surfaced.
The plane had been assigned to runway three but the pilot had asked to change to runway one. Due to the fair weather, the request was granted and the plane was cleared for landing.
This suggests that the plane could have had a technical failure when changing runways.
One private Indian airline pilot, who had flown such a plane but did not want to be named, described it as an “unforgiving aircraft” which would be hard to manoeuvre if the pilot wasn’t highly skilled or familiar with the region’s terrain.
This gives rise to another theory, that poor Nepalese safety standards could be to blame.
A lack of investment in new air technology and poor regulation has previously been an issue in Nepalese aviation.
Famously, the European Union (EU) banned Nepalese plans from entering its airspace due to safety concerns.
Following two crashes last year and in 2018 the Nepalese government had been making regulatory changes and increasing innovations to improve this poor track record.
This included the opening of the new Pokhara airport which would give easier access to the Annapurna mountain, a popular tourist destination.
Before its opening, some people had expressed concerns about the area, due to it being near two rivers as well as a landfill site which is a habitat for a large number of birds.
But even in the case of a bird strike, causing the aircraft to discontinue its approach and stall, a pilot should be able to handle this type of failure.
This point was reiterated by Mr Singh, who said that “Go-arounds are most often mishandled by crew … so again the issue is, how did the pilot cope with the failure?”
It could be a while until we find out exactly why the Yeti Airlines plane crashed during its descent to Pokhara airport. As search and rescue crews continue to look through the plane wreckage it will become clearer what circumstances led to the tragedy.