What happened
On December 30, 1998, at 07:56 UTC, an Aéropostale Boeing 737-348, registration F-GIXL, departed Lyon-Satolas airport for Nantes-Atlantique. Shortly after takeoff, while climbing through approximately 500 feet, air traffic control notified the crew that an object had been lost on the runway. The aircraft was in a clean configuration with the landing gear retracted and flaps at 5°.
After confirming no immediate issues on board, the crew entered a holding pattern at the MEDEN waypoint at 6,000 feet. To assess the extent of the damage, the crew performed a low-altitude pass with the landing gear extended and flaps at 15°. This maneuver revealed that the inner wheel of the left main landing gear (wheel number 2) was missing, though no fluid leaks were visually detected.
In preparation for a precautionary landing, the crew instructed the cabin crew to move all 59 passengers to the right side of the aircraft and prepare the cabin for an emergency situation. The aircraft returned to the circuit and initiated an approach under the callsign "Air France Juliet Victor Mayday". The pilot landed on runway 18R at 09:16 UTC, utilizing a specific technique of favoring the right gear to mitigate risks to the remaining left gear. The aircraft taxied to an adjacent taxiway to allow for passenger disembarkation via buses and jet bridges.
The investigation
The investigation focused on the loss of the wheel and the condition of the landing gear assembly. Investigators examined the recovered wheel, an Allied Signal (Bendix) model, and various fragments found on the runway. The maintenance history of the wheel was reviewed, noting it had undergone recent inspections and had 5,515 total landings since manufacture. The investigation also included a survey of similar bearings used in the airline's fleet to determine if a systemic issue existed.
Findings
- The loss of the inner wheel of the left main landing gear was the primary event.
- The crew successfully managed the emergency by performing a visual inspection and preparing the cabin for a precautionary landing.
- The loss of the wheel component occurred during the initial climb phase of the flight.
- A survey of 54 similar bearings revealed that 3.7% showed signs of damage, suggesting a potential for component wear in this specific type of bearing.