What happened
On November 17, 2013, a Boeing 737-300 QC, registration 9Q-CGD, was operating a scheduled passenger flight from Kinshasa to Kisangani, chartered by Air Kasai. The aircraft departed Kinshasa at 07:57 UTC with 127 people on board, including 120 passengers and 7 crew members.
While cruising at flight level 330, the aircraft experienced an initial engine surge (compressor stall) in the number one engine at 08:35 UTC. Although the engine stabilized temporarily, the flight continued for approximately 33 minutes under degraded conditions. At 09:05 UTC, a second, non-recoverable surge occurred in the left engine. This second event caused the N1 speed to drop and the engine' and fuel flow parameters to increase.
In response to the engine failure, the pilot in command initiated a drift-down procedure to a lower altitude. After notifying Kisangani/Bangboka approach control of the engine failure, the crew descended to flight level 190. The pilot eventually shut down the left engine completely at 09:21 UTC. The aircraft subsequently landed at Kisangani/Bangboka airport at 09:52 UTC. There were no fatalities or injuries among the 127 occupants.
The investigation
The technical investigation was conducted by a commission established by the Congolese Ministry of Transport. The investigators examined the aircraft's technical and administrative records, maintenance logs, and crew files. They also consulted with air traffic services at the relevant airports and coordinated with authorities from the United States (the state of design and manufacture) and France (the state of engine manufacture). The investigation focused on the engine's performance, the maintenance history of the aircraft, and the crew's response to the engine surges.