60 years of living dangerously

Most aviation accidents in Nepal between 1952-2022 were caused by planes flying into mountains hidden in clouds, known to air crash investigators as Controlled Flight into Terrain (CFIT).

Major air crashes in 60 years: 67

Total CFIT: 30

Total air crash fatalities in 50 years: 818

CFIT fatalities: 752 (92%)

What is it about air crashes in Nepal that very similar accidents tragically keep happening again and again in the same kind of terrain and weather?

A Nepali Times analysis of plane crash data from the past 60 years shows that 92% of the fatalities have been in accidents categorised as Controlled Flight Into Terrain (CFIT) in which an airworthy aircraft slams into a mountain hidden in cloud.

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Nepal is the most challenging country in the world for aviation because of treacherous terrain and weather. Short runways carved out of mountains add to the challenge. Weak regulatory oversight, commercial pressure, failure to follow procedures by flight crew are cited as reasons for most crashes. These sentences from past air crash investigations in Nepal all point to only one type of malfunction:

‘Crew made incorrect judgment of the deteriorating weather condition’

‘Violation of regulation to fly in VFR at all times’

‘Probable cause was continuation of the flight despite unfavorable weather conditions’

‘Ineffective safety and crew training by airline’

‘Inappropriate and insufficient crew coordination’

‘Crew’s over-confidence, casual non-compliance of SOPs about VFR.’

Nearly all major crashes in the past 60 years have occurred on mountain routes. Most mishaps were in the monsoon or during winter rains. Very few were caused by mechanical failure, loss of control, or bird strikes. There have been no fatal crashes on Tarai trunk routes in that period (see map, above).

After every CFIT, investigation reports have pointed to the same reason: failure to abide by Visual Flight Rules (VFR) while flying in the mountains in poor weather. Most cockpit crew, including the ones flying the Tara Air Twin Otter that crashed near Jomsom on 30 May, appear to have been caught unawares by a sudden change in en route weather.

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Aviation safety experts say this means pilots need to be mindful of not just the weather at the origin and destination airports, but also have precise real-time information of conditions along their flight path. A past crash report recommended equipment to beam live weather conditions on accident-prone routes like Pokhara-Jomsom. The equipment was never installed.

The Civil Aviation Authority of Nepal (CAAN) ought to take a lead by coordinating with the Department of Meteorology and Hydrology to use existing and proposed Doppler radar stations, locating them along dangerous air routes.

Webcams at critical waypoints like Lamjura, Ghorepani, Lete, and Virgin Pass could stream live images of visibility and cloud. Such weather cameras have proved their worth for bush pilots in Alaska and other far flung areas of the world. Following the latest crash near Jomsom that killed 22 people, flights are now required to have go, no-go clearance from air traffic controllers of en route weather. This requirement has grounded most Pokhara-Jomsom flights.

Read more: Crash Course, Editorial

This rule pre-supposes that CFIT incidents are mostly due to pilot error, and therefore hands the decision to controllers who may actually have even less information about en route weather.

It is the flight crew which has visual reference to conditions along the way, and are in the best position to make a judgment to fly on or turn back.

Capt Prabhakar Ghimire was a former air traffic controller with 30 years of experience flying Twin Otters and knew the terrain like the back of his hand. Initial reports of the 29 May crash say he made a steep banking climb to remain VFR and avoid cloud before impact.

Handing flight clearance based on en route weather to controllers may lead to needless cancellations, or increase pressure on pilots to fly even when the weather along the way is bad.

More loss of lives can be reduced with VFR training compliance for crew, and real-time visual en route weather information.

Serial tragedies

In 1962, a C-47 on a flight from Kathmandu to Delhi went missing. The plane with 10 passengers, including Nepal’s ambassador to India, was only found a week later.

A MI-17 helicopter carrying mountaineering guides disappeared in pre-monsoon clouds in 2002 on a flight from Makalu Base Camp to Lukla. It has never been found.

In 1991, two Airbus 310s crashed within two months of each other during the monsoon while on final approach to Kathmandu airport, killing a total of 280 people.

Another MI-17 helicopter slammed into a mountain below Kangchenjunga in 2006 in bad weather, killed 24 people that included Nepal’s pioneer conservationists.

A US Marine Corps Bell UH-1Y Venom evacuating survivors of the 2015 earthquake impacted on high terrain obscured by cloud cover in Dolakha, killing all 13 on board. In 2008, a MI-17 chartered by UNMIN flew into a mountain in Sindhuli killing all 10 passengers.

Two Twin Otters from the same airline on the same route flying in similar weather crashed at nearly the same place along the Kali Gandaki gorge about eight years apart.

Read more: Why missing planes are so difficult to find in Nepal, Nepali Times