Centurion Air Cargo Flight 164

Investigation

The Colombian Grupo de Investigacion de Accidentes opened an investigation into the crash. The U.S National Transportation Safety Board sent five investigators to assist the Colombian investigation team. The Federal Aviation Administration, aircraft-maker Boeing Co. and engine-maker Pratt & Whitney also assisted the investigation.

The 51-year-old Captain Bryant Beebe (8,874 hours total, 2,874 hours on type) was the pilot flying; the 49-year-old First officer Ivan Dankha (11,373 hours total, 2,853 hours on type) was the pilot monitoring. The 59-year-old Flight engineer Joseph Kendall had a total flying experience of 10,665 hours, with 2,665 hours on type.

Both the flight data recorder and the cockpit voice recorder were recovered and taken for an analysis. The aircraft was configured for takeoff with flaps at 10 degrees (the flaps remaining in that position until impact) with the engines at EPR between 1.69 and 1.72, when it accelerated through Vr (152 knots) and rotation was initiated. When the aircraft rotated, engine 4 lost power as the pitch went through 13 degrees nose up and the airspeed already exceeded V2 (162 KIAS), with the engine rolling down from about 1.7 EPR to 1.0 EPR within two to three seconds. That engine surged four times during that time. Engineers determined that the high-pressure turbine of engine 4, which had been installed during the last work shop visit in January 2008, was inefficient due to too large a blade tip clearance, the reduced chord, and wear of leading edges of fan blades, which resulted in an estimate loss of engine power of 5.8% and impaired stability and operability of that engine.

Engine 1 then suffered a failure of the low-pressure turbine, which resulted in ejection of engine parts through the engine exhaust. The failure originated in the third stage of the LPT, and engineers believe the failure started with the loss of a number of guide vanes or the loss of a large piece of outside air seal due to thermal damage. Although an overboost condition existed outside regular engine operation range, the application of such engine power for a short period of time should not have caused an engine failure. The exact cause of the engine failure could not be determined.

Investigators noted that engine 2 suffered a rapid decline of EPR and recovery of EPR for five times, each lasting for about two to three seconds, with the surges occurring at eight-seven, thirty-three, thirteen, and three seconds before impact, respectively. Eventually, the aircraft crashed.

On 22 August 2011, the investigation board finally published the final report. The crash was caused by the failure of two engines of the aircraft, engine 4 and engine 1. Engine 4 suffered a non-recoverable surge during rotation. The aircraft then struggled to climb. As the flight crew were conducting the emergency procedure, the engine 1 failed. With two engines malfunctioning, the aircraft was unable to sustain flight in its configuration. It began to experience problems with a third engine, the inboard left-hand JT9D, which repeatedly surged.