Nepal plane crash: Did Yeti Airline's pilot ‘unintentionally’ switch off engines, plunging 71 to death?

Yeti Airlines plane crash at Pokhara: The fatal airplane crash that killed all 72 people on board a month ago, might have been due to a human error. The preliminary reports of the crash has been released wherein the investigators have suspected a human error that took the lives of 72 people on the Yeti Airlines flight including five Indians. 

 The fatal crash

On 15 January, The Yeti Airlines flight 691 took off from Kathmandu's Tribhuvan International Airport, crashed on the Seti River gorge between the old airport and the new airport in the resort city of Pokhara. 

There were 72 people including four crew members onboard the ATR-72 aircraft when it crashed, but rescue officials have so far managed to recover only 71 bodies with the other missing passenger presumed dead.

What caused the crash?

According to the preliminary report, the Yeti Airlines flight lost thrust and fell after the propellers of both engines went into a feathered position

Investigation

The black boxes recovered from the crash site had been sent to Singapore for further investigation as to why the crash happened.  However, Gyanendra Bhul, information officer at Civil Aviation Authority of Nepal (CAAN) had confirmed that the weather was not the issue, but ‘technical reasons’ caused the fatal carsh.

While initially onlookers had blamed the weather in the Himalayan country for the crash, a preliminary probe's official statement suspects human error. 

Did the pilots accidentally shut down power to the engines?

The plane had crashed just ‘10 to 20 seconds’ before landing.  The investigation report said the pilot who was primarily flying the aircraft handed over the controls to the pilot monitoring before it crashed.

An analysis of the cockpit voice recorder and flight data recorder showed the propellers of both engines went into "feather in the base leg of descending."

However, investigators have mentioned that ‘it is rare for the propellers of both engines to come to a feathered position’. This factor has also been mentioned in the 14-page preliminary report posted on the website of the Ministry of Tourism, Culture and Civil Aviation of Nepal.

“During the time of the crash, the prevailing visibility was 6 km and the sky was almost clear with only a few clouds,” points out the preliminary report, further eliminating the bad-weather-low-visibility aspect of causing a crash.

According to experts, the pilots unintentionally pulled the condition levers causing the engine to shut down and feather the propellers. Each lever starts and stops the fuel supply, and controls the idle speed for its respective engine.

“We are waiting for a detailed report. We cannot ascertain what happened before that,” said a probe committee member.

“Yes, there is also the issue of flaps. There are questions about why the pilots delayed extending the flaps. The routine checklists were not followed. There are many factors to look at,” Joint Secretary at the Tourism Ministry Buddhi Sagar Lamichhane - a senior member of the probe committee -- was quoted as saying by The Kathmandu Post newspaper.

There were two captains on the plane. Captain Anju Khatiwada was in the process of obtaining aerodrome familiarisation for operating in Pokhara, and Captain Kamal KC was the instructor pilot on this training flight.