Investigation Summary
During the approach to Kathmandu, the crew experienced a technical fault with the inboard flaps. The Captain, who had 13,173 total flying hours (including 3,552 on the A310), became increasingly frustrated while communicating with a trainee air traffic controller who had only nine months of experience and limited English proficiency. The First Officer, with 6,058 flight hours, failed to challenge the Captain's erratic decisions, representing a significant CRM breakdown. The crew requested a diversion to Calcutta but then decided to attempt the approach again. They attempted to input a 180-degree turn into the Flight Management System (FMS) to return to the Romeo waypoint, but because the aircraft had already passed the waypoint, the FMS failed to execute the turn. The captain then manually initiated a turn but inadvertently completed a full 360-degree circle, leaving the aircraft on its original fatal northerly heading toward the Himalayas. The Ground Proximity Warning System (GPWS) sounded for 16 seconds, but the crew dismissed it as a false alarm until seconds before impact at approximately 16,000 feet.
Final Conclusions
The investigation concluded the primary cause was the crew's failure to follow established approach procedures and maintain situational awareness. Contributing factors included ineffective communication between the crew and ATC, the controller's failure to alert the crew of their incorrect heading, and the crew's preoccupation with a minor mechanical flap malfunction.
Video Analysis
The Kathmandu Disaster | Thai Airways Flight 311 — An analysis of the 1992 crash of Thai Airways Flight 311 into the Himalayas due to navigational errors and communication breakdowns.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Systems & Failure Modes
GPWS
Ground Proximity Warning System; provided alerts that were ignored by the crew.
Inboard Flaps
A mechanical fault in the flap system initially distracted the crew from navigation.
FMS
Flight Management System; the crew failed to properly program or monitor the heading during the missed approach.
Interesting Facts
- 01The aircraft was only 5 years old at the time of the accident.
- 02Kathmandu Airport lacked primary radar at the time of the crash.
- 03The crash site was located approximately 37 miles north of Kathmandu at an altitude of 16,000 feet.
- 04All 99 passengers and 14 crew members perished in the impact.
- 05The investigation was hampered by the extremely rugged terrain and monsoon weather.
Safety Actions & Advisories
Radar Installation
Following the crash and the subsequent PIA 268 disaster, a modern Raytheon radar system was commissioned at Kathmandu in 1997. This system was funded by a grant from the Japanese government to provide controllers with better situational awareness in the mountainous region.
CRM Training
Thai Airways enhanced Crew Resource Management training to address captain-centric authority issues and communication.
Location
APPROXIMATE AREA ONLY · This position predates coordinate provenance tracking. Treat it as an approximate marker for the area, not the accident site. No map is shown, because a marker here would imply a precision the record does not have.
Reported location: Langtang National Park, Nepal