Investigation Summary
The approach to Kathmandu is notoriously difficult due to the surrounding high terrain. Flight 268 was performing a 'Sierra' approach from the south. This approach required the aircraft to pass over seven specific reporting points at designated altitudes. Due to a navigational error or misinterpretation of the approach chart, the crew consistently flew the aircraft exactly one step ahead of the required profile—descending to the altitude required for the next waypoint before they had actually reached the current one. This resulted in the aircraft being approximately 1,000 feet lower than it should have been throughout the final stages of the approach.
Final Conclusions
The primary cause of the accident was the flight crew's failure to follow the established instrument approach profile. Specifically, the crew initiated each step of their descent one reporting point too early. Contributing factors included the lack of a Ground Proximity Warning System (GPWS) that could provide timely warnings in such steep terrain, and approach charts that were deemed complex and potentially confusing to the flight crew.
Video Analysis
Did This Chart Error Crash Flight 268? — A PIA jet crashes into a Himalayan mountainside during approach to Kathmandu. With no radar and a complex descent chart, investigators ask: did a simple misreading seal the fate of Flight 268—and its 167 passengers?
Watch on YouTube ↗If playback is blocked, the owner has disabled embedding — use the link above.
Systems & Failure Modes
GPWS
The Ground Proximity Warning System did not provide sufficient warning due to the steepness of the terrain and the aircraft's configuration.
Approach Charts
The Jeppesen charts used by the crew were scrutinized for being difficult to read, potentially contributing to the altitude errors.
Interesting Facts
- 01This remains the deadliest aviation accident to occur in Nepal.
- 02The aircraft was 1,000 feet below its cleared altitude at every step of the approach.
- 03The crash site was located on Bhattedanda Hill, just south of the Kathmandu Valley.
- 04The flight crew consisted of four members: Captain, First Officer, and two Flight Engineers.
- 05Investigation found no evidence of technical failure or engine malfunction prior to impact.
Safety Actions & Advisories
Approach Chart Redesign
Recommendations were made to simplify the presentation of altitude constraints on approach charts for high-terrain airports.
Radar Installation
The accident accelerated the installation of modern secondary surveillance radar at Kathmandu to better monitor aircraft altitudes.