On September 28, 1992, Pakistan International Airlines Flight 268 was approaching Kathmandu when a seemingly routine descent turned into one of Nepal’s deadliest aviation disasters.
The Airbus A300B4-103, registration AP-BCP, was flying from Karachi to Tribhuvan International Airport with 155 passengers and 12 crew members. None survived.
The flight had proceeded normally until it entered Nepalese airspace for the demanding Sierra approach to Kathmandu. Because the airport is surrounded by high mountains, aircraft had to follow a carefully controlled series of altitude and distance restrictions.
Flight 268 was cleared to approach from the south, with the crew required to remain at specific altitudes while passing successive reporting points before descending toward the airport.
The aircraft contacted Kathmandu controllers and reported its position and altitude. But during the approach, the crew began descending earlier than required. The descent profile gradually placed the A300 below the prescribed altitude while it remained on the correct approach track.
At 16 nautical miles from the Kathmandu VOR, the aircraft was already about 1,000 feet below its cleared altitude. By 10 DME, it was approximately 1,300 feet too low.
At about 2:30 p.m. local time, Flight 268 struck the southern slope of Bhattedanda in the Mahabharat Range at roughly 7,300 feet above sea level. The aircraft broke apart on impact, killing everyone aboard.
The mountain was around 8,250 feet high, leaving the aircraft dangerously low as it followed the approach path through cloud and poor visibility.
The investigation found no evidence of an aircraft malfunction, extreme weather, or terrorism. Flight recorder data revealed that the aircraft had effectively flown the approach “one step ahead,” beginning each descent segment too early.
The cockpit voice recorder did not provide useful flight-deck conversation, but the flight data recorder established the aircraft’s altitude and flight path before impact.
Investigators concluded that pilot error was the principal cause, but several contributing factors were identified. The Kathmandu approach was exceptionally complex, the approach charts provided to PIA crews were considered unclear, and the lack of radar meant controllers could not see the aircraft’s dangerously low altitude.
Investigators also found that controllers did not intervene despite receiving accurate altitude reports from the crew.
The steep terrain and cloud conditions further reduced the opportunity for visual recovery, while the ground-proximity warning system was unlikely to provide sufficient warning because of the rapidly rising terrain.
The crash prompted recommendations for clearer and standardized navigation charts and a less complicated approach procedure into Kathmandu.
The disaster remains the deadliest accident in Pakistan International Airlines’ history and one of Nepal’s most significant aviation tragedies, claiming 167 lives in a matter of seconds.
