KATHMANDU, March 3: A probe commissioned by the government on Buddha Air’s Twin Otter crash, in which all 19 persons on board lost their lives, has concluded human error as the major cause of the accident.
The final investigation report prepared by the five-member commission concluded that flight crew did not follow standard route that led to a loss of situational awareness, resulting in the accident.
Buddha’s Beach B1900D 9N-AEK crashed at Kotdanda, Bishankhu Narayan, in Kathmandu on September 25, 2011 while returning from a mountain flight. Sixteen passengers and 3 crew members lost their lives in the crash.
“The aircraft flown by Captain Padma Adhikari entered into a cloud and started descending while still inside the cloud. This caused the aircraft to hit tree tops on the hills,” reads a synopsis of the report distributed to the press.
“Incompatible and incorrect procedure contrary to standard operating procedure contributed to the accident,” said Rajesh Raj Dali, Chairman of the commission.
According to him, the pilot had flown the aircraft 5000 feet above the ground, whereas existing standards required her to fly at 6,000 feet before descending.
“Sadly, this lack of compliance to Standard Operating Proceedure and fatigue of pilot led to the accident,” he said, adding that the commission during its investigation had found that Captain Adhikari was undergoing irritation due to comments passed on by airport staffs on her personal life.
Likewise, J B Tamrakar, the other captain on board, was found to be flying ATR, Twin Otter and Beechcraft, even though international practice requires pilots to operate one type of aircraft only.
“Just a day before the accident, Captain Tamrakar had flown an ATR, and was assigned to fly the ill-fated aircraft early next morning. This shows that Captain Tamrakar did not have enough rest before the operation of the aircraft,” Dr Ranjit Singh Baral one of the commission members said.
The commission said the fatigue of Captain and poor visibility could have led to the error, causing the accident.
The commission has recommended Civil Aviation Authority of Nepal (CAAN) to enforce all operators to install Terrain Awareness Warning System.
The commission has also recommended operators to develop line operations safety audit (LOSA), critical organizational strategy aimed at developing counter-measures to operational errors.
The commission urged operators to regularly download and analyze dialogues recorded in Cockpit-Voice Recorder to discourage unnecessary communications in the cockpit.
The other safety recommendation of the commission asks CAAN and operators to develop flight time and duty period limitations based on the numbers of sector per day, type and time of flight operations. “This will help ensure that pilots have enough rest before operating flights,” Suresh Acharya, member secretary of the commission.