An investigation into the crash at Kathmandu airport on 28 September last year of a Lukla-bound Sita Air flight has concluded that it was caused by passenger and cargo payload that exceeded the plane’s maximum takeoff weight.
Nineteen people, including 12 tourists, five Nepali passengers and crew were killed when the Dornier aircraft stalled soon after takeoff, crashed and burned only 450m east of the runway on the banks of the Manohara. The investigation report said the plane weighed 5,914kg when the maximum takeoff weight allowed for a Lukla flight is 5,836 kg. The aircraft manifest logged 5,834 kg, but this did not include extra baggage onboard.
Airlines usually calculate passenger load based on 75kg per passenger, but many of the non-Nepali passengers weigh much more on average. The pilots had a conversation about bird activity, but took off anyway. However, air traffic control noticed abnormal climb after takeoff and asked if there was a problem. The pilot replied “Uncertain … bird hit.” Airport CCTV cameras also show sparks coming out of the starboard engine during the takeoff run. The plane then turned and nosedived into Manohara soon after. Stall warnings sounded in the cockpit before impact.
The report concludes that the crash was a combination of overloading, engines producing deficient power, and a possible bird strike. It has recommended increasing the calculation for average weight of a foreigner to 95kg and for a Nepali to 75kg.