Synopsis
On 17 December 2023, at approximately 14:09 UTC, a Boeing B737-36N registered as TN-AKC, operated by Africa Airlines, experienced a wheel detachment during takeoff from runway 23 at Maya Maya Airport (FCBB) in Brazzaville, Republic of Congo. The aircraft was performing flight AAT108, a commercial passenger service to Agostinho Neto Airport (FCPP) in Pointe Noire. On board were two flight crew, three cabin crew, and 54 passengers (including one child and two infants). The incident resulted in the detachment of wheel No. 2 from the left main landing gear, along with damage to the associated brake assembly and the outboard bearing.
Sequence of Events
The crew established contact with FCBB tower at 13:54. After pushback and taxi, takeoff clearance was received at 14:10. During the takeoff roll, a fire and rescue service agent observed a wheel detaching from the aircraft and informed the tower at 14:11. The controller relayed this to the crew, who decided to continue the flight to Pointe Noire. The crew requested to level off at Flight Level 240, which was approved. At 14:23, the crew deviated 30 degrees from course due to weather. Shortly after, they reported a cracked L1 cockpit windscreen and a pressurization problem, requesting descent to FL 100, which was authorized. The aircraft landed safely on runway 17 at Pointe Noire with emergency services standing by.
Damage to Aircraft
The left main landing gear wheel No. 2 detached in flight. Subsequent examination revealed damage to the outboard bearing and the wheel brake assembly. No other structural damage was reported.
Aircraft Information
The aircraft was a Boeing 737-36N (MSN 28560), registered TN-AKC, operated by Africa Airlines. The maintenance history indicated recent inspections by South African maintenance organizations.
Investigation and Analysis
The investigation was conducted by the Bureau des Enquêtes et des Accidents d'Aviation (BEA) of the Republic of Congo, with assistance from the U.S. NTSB, the South African CAA, the FAA, and Timken (bearing manufacturer). Analysis focused on the detached wheel and its components.
Findings and Causes
Probable Cause
The main cause of the incident was the premature failure of the outboard bearing of wheel No. 2 on the left main landing gear, due to a lubrication deficiency in service. This deficiency led to overheating and failure of the bearing, resulting in the wheel separating in flight.
Contributing Factors
- Insufficient lubrication during wheel maintenance operations.
- Failure to detect the anomaly during periodic visual inspections.
- Non-compliance with manufacturer's instructions for bearing checks.
Safety Recommendations
The BEA issued safety recommendations to address maintenance practices and inspection procedures to prevent recurrence.