The report said Captain Sultan had slept little the night before the flight and had been unaware of new rules in Bangladesh that required international flights to have air clearance before departing from Dhaka, leading to confusion when he prepared for takeoff.

He was also considering whether to resign from US-Bangla Airlines over comments from a colleague who had questioned his competency. In the air, Captain Sultan seemed “very insecure,” the report said. He acted aggressively with other crew members, smoked in the cockpit and complained repeatedly about the colleague’s criticism. (She was not on board.)

Once in Nepalese airspace, Captain Sultan failed to follow standard procedures at a critical stage of the landing phase at Tribhuvan International Airport, the report said. This led to the loss of “situational awareness” that had prevented him from properly judging the angle of approach to the runway.

The report also blamed air traffic controllers in Nepal for a “lack of assertiveness” in safely guiding the plane, a twin-engine turboprop that can carry up to 78 passengers, to the ground.

“Landing was completed in a sheer desperation after sighting the runway, at very close proximity and very low altitude,” the report said.

Captain Sultan, his co-pilot and the two other crew members on board were among those who died in the crash. The report was compiled using cockpit voice recordings, closed-circuit television footage, a flight data recorder and interviews with air traffic controllers and Nepali and Bangladeshi officials.

Though an experienced pilot, Captain Sultan had struggled in the past. In 1993, he was let go from the Bangladesh Air Force in connection with his depression, the report said. He was later cleared to work again and flew planes for several airlines before joining US-Bangla Airlines in 2015, the year after it began operations.