What happened
On the morning of 10 February 2022, a Boeing 737-800, registration ZS-ZWD, departed Lanseria International Airport for a scheduled service to Cape Town International Airport. The flight was carrying 157 passengers and seven crew members.
While climbing through flight level 260, the flight crew heard a loud bang, and the aircraft experienced a sudden leftward yaw. The pilot flying immediately halted the climb between flight level 2/60 and 270 to assess the situation. Following the incident, the autopilot disconnected, and warning lights indicated a failure in the number 1 engine. Although the engine continued to run at a reduced power setting, the crew declared a MAYDAY and initiated an emergency descent to flight level 230.
The crew decided to divert to O.R. Tambo International Airport. Following standard procedures, the pilots shut down the malfunctioning engine and performed a single-engine approach. The aircraft landed safely on runway 03R, where emergency services inspected the engine and runway for debris or leaks. No injuries were reported among the passengers or crew.
The investigation
An investigation by the SACAA AIID focused on the mechanical state of the engine and the circumstances surrounding the failure. A borescope inspection of the number 1 engine revealed significant internal damage, including discolouration in the hot section and the shearing of high-pressure turbine blades, some of which had broken out of the disk.
While the aircraft sustained substantial damage to the engine and the left-side leading edge of the horizontal stabilizer, the airframe itself was found to have no pre-existing defects that contributed to the event. The investigation was complicated by the fact that the operator, Comair Limited, entered liquidation in June 2022. Consequently, the engine could not be sent to the manufacturer for a full teardown inspection, and the definitive cause of the internal component failure remains undetermined pending the appointment of a new owner.