The flight carrying 71 people from Dhaka caught fire as it landed in Kathmandu.

The pilot of a US-Bangla Airlines plane that crashed in Nepal, killing 51 people aboard last March "seemed to have an emotional breakdown", according to a final report on the Himalayan nation's worst aviation disaster in 26 years.



The flight carrying 71 people from Bangladesh's capital Dhaka caught fire as it landed in Kathmandu. It was initially thought that poor communication with air traffic control was to blame for the disaster.



But investigators now say the pilot was ranting to crew members and even smoking in the cockpit, due to stress, the BBC reported.



Nepal's Accident Investigation Commission said in its report that the 52-year-old captain of US-Bangla Airlines flight BS211 was "very much emotionally disturbed and stressed" because a female colleague, who was not on board the plane, had "questioned his reputation" as a good flight instructor.



Investigators say the pilot's vocal pitch and the language he was using "indicated that he was agitated and experiencing high levels of stress" even when speaking to ground control in Dhaka before take-off.



According to the black box voice recorder and reports from surviving passengers, the pilot smoked in the cockpit and "engaged in unnecessary, unprofessional and lengthy conversation even in the critical phase" of the flight.



The pilot was released from the Bangladeshi Air Force in 1993 because of depression, the report said, but was later declared fit to fly civilian aircraft.



"This state of mind with high degree of stress and emotional state might have led him to all the procedural lapses. This, together with the failure on the part of both the crew to follow the standard operating procedure at the critical stage of the flight, contributed to the loss of situational awareness," the report said.



It added that the 25-year-old first officer may have been reluctant to be more assertive during the final approach and landing because of the captain's experience and authority.



Because they had lost "situational awareness", the crew failed to realise the flight had deviated from its intended path until it was too late.



They missed the runway at Kathmandu's Tribhuvan International Airport and ended up flying in an incorrect position in the dangerous mountainous terrain.



Both pilots, the two cabin crew and 47 passengers died as a result of the accident.