What happened
On the morning of 7 March 2022, a Boeing 737-800, registration ZS-ZWB, was operating a scheduled domestic flight from Lanseria International Airport to Cape Town International Airport. The aircraft was carrying 135 passengers and six crew members.
While climbing through flight level 210, the flight crew heard a loud bang originating from the left engine. Flight data recorder analysis confirmed that the number 1 engine experienced a sudden drop in fan and core speeds, followed by a total loss of power and a drop in oil pressure to zero. The crew immediately initiated an emergency descent and declared a MAYDAY, requesting a diversion to O.R. Tambo International Airport. The aircraft landed safely on runway 03R approximately 20 minutes after the failure, operating on a single engine. There were no injuries to the passengers or crew.
The investigation
An investigation by the SACAA AIID focused on the mechanical state of the engine and the crew's response. Investigators performed a borescope inspection of the failed engine, which revealed internal discoloration and the failure of components within the hot section. Physical inspection also showed that debris from the engine failure had caused substantial damage to the left engine, the left leading edge of the horizontal stabilizer, and the lower surface of the inboard flaps.
However, the investigation reached a standstill regarding the specific root cause. Because the operator, Comair Limited, entered liquidation following a High Court order in June 2022, the engine could not be shipped to the manufacturer for a full teardown inspection. The investigation remains subject to reopening once a new owner of the aircraft is identified and agrees to proceed with the technical teardown.
Findings
- The flight crew was properly licensed, medically fit, and followed all standard operating procedures and emergency checklists.
- The aircraft was properly maintained and had no recorded defects prior to the incident.
- Weather conditions at the time of the incident were clear and did not contribute to the failure.
- The failure of the hot section components within the number 1 engine was the primary driver of the incident.
- The decision to divert to O.R. Tambo International Airport was appropriate given the aircraft's position during the climb.