Why missing planes are so difficult to find in Nepal
A Twin Otter that went missing on Sunday morning in bad weather in Nepal had still not been located till nightfall, and the Nepal Army said clouds and darkness had forced it to call off an aerial search.
However, ground teams are said to be trekking to a site near Lete that was geo-located through the missing pilot's mobile phone that is still working. There were also reports, including a photograph, reportedly taken by shepherds and not yet verified, that appear to show a burning wreckage near the top of a ridge.
The Tara Air DHC-6 aircraft with 22 people on board was on a flight from Pokhara to Jomsom in poor en route weather. One eye witness on the ground near Tukuche said he had seen the plane turn back in cloud.
The Twin Otter aircraft lost contact with Jomsom air traffic control after passing abeam Ghorepani Pass. There are 13 Nepalis on board, including three crew members, 4 Indians and two Germans.
Concerns had been raised about Nepal’s poor air safety record, but there has been no major mishap on a domestic flight since 2016.
The Pokhara-Jomsom air route is tricky because it passes through the world’s deepest gorge between Annapurna and Dhaulagiri and has treacherous winds and clouds. There have been several fatal accidents on this route mostly due to controlled flight into terrain (CFIT) during bad weather.
Most air accidents in Nepal happen around the monsoon season when disoriented pilots fly into mountains hidden by clouds. The terrain is also what makes it difficult to find the wreckage of missing aircraft, and this is made worse when there is bad weather.
In fact, one aircraft that went missing in 2002 has never been found. The helicopter ferrying mountaineering expedition guides from Makalu Base Camp to Lukla was lost almost exactly 20 years ago on 31 May 2002.
The Asian Airlines Mi-17 helicopter was carrying 8 mountaineering guides and two crew members including a Russian pilot and could not be found after weeks of aerial and ground search in rugged terrain during the monsoon, and the hunt was abandoned.
Members of an ornithological expedition in the Makalu Barun National Park had heard the plane circling over a remote part of the Arun Valley. It is thought that the helicopter hit a mountain and was buried in an avalanche triggered by its impact.
Because flying over the Himalaya is challenging due to terrain and weather, the same factors also make search and rescue more difficult. As far back as August 1962, a Royal Nepal Airlines DC-3 strayed off course on a flight from Kathmandu to Delhi and crashed killing all four crew and six passengers, including Nepal’s ambassador to India.
The plane was only located ten days later by an Indian Air Force plane on a remote mountain in Dhorpatan. A Pilatus Porter rescue plane that was sent to the area also crashed.
When a Thai International Airbus 310 disappeared on a flight from Bangkok to Kathmandu in July 1992, it could not be located for four days because it had gone completely off course during the monsoon and crashed in Langtang National Park 20km north of Kathmandu. With 113 fatalities, this was the second-worst disaster in Nepal’s aviation history.
Weather and terrain were also factors in difficulties to locate crashes of other flights, including the Lumbini Air Twin Otter that hit a mountain on a flight from Jomsom to Pokhara in the monsoon of 1996, killing 18 people.
When a Mi17 helicopter carrying 22 passengers, including Nepal’s top conservationists disappeared after taking off from Gunsha below Kangchenjunga in September 2006, the wreckage could not be found for several days.
In 2014, a Nepal Airlines Twin Otter in Argakhanchi could only be located after a day, and that only because the mobile phone of a passenger could be traced.