Here's some details about the TG311 crash on 31Jul1992. This is my summary of the facts from a published (non-copyrighted) case, Koirala v. Thai Airways Int'l, Ltd., 126 F.3d 1205 (9th Cir. 1997), so no infringement here.
Located in a valley surrounded by high mountains, Kathmandu's Tribhuvan Int'l Airport has a reputation of being one of the most difficult airports in the world in which to land. Planes face a steep approach with full extension of wing flaps during the entire descent. At the time of the crash, the airport had no radar, forcing ATC to determine aircraft location and provide instructions to planes by air-to-ground and ground-to-air radio communications. Flying TG311 were Captain Preeda Suttimai and FO Phuntat Boonyayej, both properly licensed and certified with substantial experience flying into Kathmandu.
The weather on the night of the crash was cloudy and rainy, providing little visibility and requiring the crew to depend entirely on navigational instruments to fly the plane. At 6:46:07 Coordinated Universal Time, ATC authorized the captain to execute a landing approach. At that time the aircraft was flying at heading 022, or twenty-two degrees east of due north. The crew realized at 6:47:34, however, that the wing flaps had failed to extend properly, making the landing too dangerous to attempt. The crew requested permission to divert to Calcutta, but the wing flaps properly extended at 6:49:05 before ATC had a chance to respond. At that time, however, the plane was too far north and too high to begin a safe descent to the runway.
The captain requested four times between 6:49:08 and 6:50:21 for clearance to turn left and fly south to point "Romeo", a position 41 miles south of the airport where the plane had made its initial approach. ATC did not respond to these requests.
Around 6:50:50, the flight crew began a climbing right turn, without first having reqested or obtained clearance from ATC. The FO notified ATC at 6:51:55 of the right turn and the flight crew's intention to climb to 18,000 ft. and return to point Romeo. ATC ordered the plane to descend to 11,500 ft. and maintain that altitude, which the crew did.
Between 6:52:06 and 6:59:39, ATC on six separate times authorized the plane to head south and return to point Romeo. Rather than turning 180 degrees on heading 202, the flight crew mistakenly executed a 360 degree turn, which put them on their original heading of 022 toward the mountains.
The flight crew tried to input and display the location of point Romeo on their Flight Management System, but the FMS was incapable of displaying navigational points located behind the plane. Preoccupied with their unsuccesful efforts to program the FMS, the flight crew ignored all the navigational instruments which indicated a northerly heading of the plane. The flight crew believed that they were heading south and could not understand why they weren't able to display point Romeo on the FMS.
By 6:59:56, the flight crew had been continously trying to program the FMS for approximately six minutes. At 6:59:58, the FO realized that the plane was heading north, but when he tried to communicate this fact to the captain, the captain did not understand the warning. Twenty-eight seconds later, at 7:00:26, the plane crashed into the side of mountain 23 miles north of Kathmandu at 11,500 feet altitude and a ground speed of 300 knots, killing all 99 passengers and 14 crew members instantly.
Relatives of seven of the passengers brought a succesful action in the U.S. under the Warsaw Convention. The court held that the crash resulted from the flight crew's "wilful misconduct" in failing to monitor their navigational instruments. This finding of wilful misconduct allowed the relatives to recover more than the $75,000 liability limit normally in place under the Warsaw Convention.