Severe weather, negligence, and a malfunction in the plane’s terrain awareness and warning system led to the crash of Tara Air Flight 197 on May 29 last year, killing all 22 people on board, a government investigation has concluded.

The de Havilland Canada DHC-6 Twin Otter with registration number 9N-AET departed at 09:55 from Pokhara airport and lost contact with air traffic controllers about 12 minutes later at 10:07. The wreckage was located 20 hours later on a mountainside of Sano Sware Bhir in Thasang of Mustang.

There were three crew members and 19 passengers on board, including two German nationals, four Indians, and 13 Nepali citizens.

This was Tara Air's second deadly accident on this route, after the Flight 193 crash in 2016.

The investigation commission on Wednesday issued a press statement identifying the malfunction in the plane’s terrain awareness and warning system—the key cause behind the flying pilot losing situational awareness and hitting the mountain.

The commission has identified other eight contributing factors.

According to the report seen by the Post, the investigators found that the plane’s terrain awareness and warning system, the mandatory equipment installed to forestall unintentional impacts with the ground, was not functioning.

“The terrain awareness and warning system provided the warning for the flying pilots to avoid the terrain three times, but the sound was not heard in the cockpit,” said one investigator, who wished not to be named.

The Post talked to two investigators working on the case.

“As the ground proximity alerts were inhibited or switched off or malfunctioned, Captain Prabhakar Ghimire, the pilot-in-command, did not know how close he was with the terrain as he was flying in bad weather.”

“There would have been no crash if the ground proximity alert system was switched on or in a proper condition to alert the flying captain,” the first investigator said.

The Pokhara-Jomsom is a challenging route. Pilots have to fly at the world's deepest gorge that goes down three miles vertically between Dhaulagiri and Annapurna mountains.

The investigators observed that Captain Ghimire knew the terrain awareness and warning system was malfunctioning and decided not to take the risk to land at the Jomsom airport in such weather conditions.

“Captain Ghimire decided to climb and gain altitude to a safer position to avoid the fast-moving clouds,” said the first investigator. “It was an instrument meteorological condition (IMC), and as per the rules pilots are not allowed to fly with visual references under visual flight rules (VFR) in such conditions,” said the investigator. “Typically, this means he was flying in cloudy or bad weather.”

But Ghimire was a “zero risk” taker, his peers say.

What forced him to fly by violating the standard operating procedure?

“Captain Ghimire made a shocking statement before the crash,” investigators say.

“Yesto weather ma pani udnee ho? [Why fly in such weather?],” the second investigator who heard the conversation recorded in the cockpit voice recorder of the crashed plane quoted Captain Ghimire as saying.

“Who would have instigated him to fly in such bad weather conditions?” asked the investigator. “As per the International Civil Aviation Organization Annex 13, we cannot blame anyone. The Civil Aviation Authority of Nepal, the country’s civil aviation regulator, however, has to conduct a separate investigation on this issue.”

Tara Air Flight 197 from Pokhara to Jomsom, at 6:15 am, was the first scheduled flight on that day.

But it got delayed due to the poor weather condition. Before it took off, two planes of Summit Air departed for Jomsom, one of them just minutes ahead.

Then Captain Ghimire followed. He was in communication with the pilots of Summit Air about the weather condition.

Both Summit Air’s planes flew in bad weather conditions, the report said.

Luckily for the passengers of Summit Air, the planes completed their flights without any problem.

The third plane flown by Ghimire, however, crashed.

“Summit Air’s pilots made two differing weather reports,” the second investigator said.

“The air traffic controller in Jomsom had been informed of good en route weather conditions, while Captain Ghimire was told that there were a few patches of clouds.” “The conversation recorded in the cockpit voice recorder shows Summit Air pilots instigated Captain Ghimire to follow them by maintaining 12,500 ft flight level.”

He flew.

After a few minutes into the flight Ghimire lambasted the Summit Air pilots.

He said, “Why do you fly in such weather?”

“The bad reporting culture led to the loss of 22 lives,” said the first investigator.

“This kind of accident happens due to the country’s regulatory body’s poor supervision capacity.”

The investigators concluded that the probable cause of the accident was the flight crew's failure to monitor and maintain proper course while inadvertently flying in bad weather conditions.

The contributing factors to the accident were: the flight crew's failure to follow the company’s standard operating procedure, loss of situational awareness, deteriorating en-route weather, a less experienced co-pilot for the sector and high crew gradient, which means the crew would not at all contest the captain’s decision.

According to the report, the flight on such a critical route should not have had a little-experienced co-pilot.

The investigators found that all cockpit duties were undertaken by Captain Ghimire, which impaired his performance.

“There are issues in Nepal’s flying sector on the command and decision-making power hierarchy,” said the second investigator.

The co-pilot did not respond to the situation.

“This is only one case. There are many autocratic cockpits in Nepal, where the seniors take no account of the opinions of the other crew. They rarely delegate power to the co-pilot.”

Buddhi Sagar Lamichhane, member secretary of the investigation commission, said that they have sent the final draft report of the crash to ICAO and other countries concerned for a review before making it available to the public.

“The report will be publicly available after 60 days.”