Background
On 27 November 2010, the crew of the mishap aircraft flew from Fujairah (UAE) to Jinnah International Airport (JIAP), Karachi, Pakistan, arriving at 1000 UTC. The aircraft carried a 9-ton packaged Boeing 747 engine and had previously flown from Kandahar to Fujairah. The crew consisted of an Aircraft Commander, Second Pilot, Navigator, Flight Engineer, Flight Radio Operator, and Flight Operator.
Pre-Flight Operations
After landing at JIAP, the crew was transported to the Regent Plaza hotel in Karachi, where they stayed for at least 8 hours. The aircraft was refueled at JIAP, with a total of 74 tons of fuel onboard. A cargo load of 30.5 tons was then loaded. The aircraft mass was 197 tons with its center of gravity at 30% Mean Aerodynamic Chord (MAC) before the mishap flight.
The flight was scheduled to depart at 2025 UTC on 28 November 2010, on a route from Karachi to Khartoum to Douala, Cameroon, delivering humanitarian aid (tents). The crew arrived at the airport around 1900 UTC. Weather conditions were satisfactory.
Departure and Accident
After starting engines, the crew taxied the aircraft to Runway 25L and informed the air traffic controller that takeoff would occur in 3 minutes. The aircraft took off at 2048 UTC. According to radar data, the aircraft climbed to 600 feet, then began descending and disappeared from the radar screen. The air traffic controller received no emergency communication from the crew. The aircraft crashed at approximately 2050 UTC on a bearing of 070 degrees, about 2 nautical miles from JIAP, at coordinates N24°53.651', E067°06.406'.
Probable Cause
The official investigation determined the probable cause: uncontained failure of the 2nd stage disk of the low-pressure compressor of Engine #4 due to fatigue fracture. This resulted in an in-flight fire and damage to adjacent areas of the right wing and flaps, to an extent that the flight could not be sustained. The engine had been used beyond its manufacturer's assigned life without assessment and life enhancement by the manufacturer, leading to the uncontained fatigue failure.