What happened
On August 23, 2022, an Airbus A300B4-203F, registration YV560T, was performing a cargo flight from Maiquetía, Venezuela, to Bogotá, Colombia. After a successful initial leg, the aircraft departed Bogotá for its return flight to Venezuela. Shortly after takeoff, the crew attempted to retract the landing gear, but the lever failed to move to the fully upright position.
Following the application of the Quick Reference Handbook (QRH) procedures for the landing gear lever interlock, the crew was unable to resolve the issue and decided to return to El Dorado International Airport. During the landing roll, a significant explosion occurred accompanied by intense vibration and resistance on the right side of the aircraft. The aircraft decelerated and came to a stop near taxiway K3. Emergency services responded to the scene, applying extinguishing agents to the right main landing gear. There were no injuries among the six occupants.
The investigation
The GRIAA investigation focused on the mechanical failure of the landing gear and the subsequent tire bursts. Investigators examined the landing gear system, the maintenance records, and the hydraulic pressure levels in the pitch dampers. The investigation also reviewed the crew's execution of the landing checklist and the operator's maintenance inspection protocols.
Findings
- The primary cause of the tire explosions was the failure to deactivate the autobrake system prior to landing. Because the landing gear failed to retract, the autobrake system remained set to the 'MAX' position and did not disarm automatically.
- The high kinetic energy from a landing weight of 120 tons at a ground speed of approximately 130 knots, combined with the maximum braking force, exceeded the thermal absorption capacity of the braking system, causing the explosion of four main landing gear wheels.
- A loss of hydraulic pressure in the landing gear pitch damper created an asymmetry in the proximity sensors, which prevented the landing gear from retracting correctly.
- There was an identified asymmetry in the 'weight on wheels' sensors, contributing to the gear retraction failure.
- Maintenance deficiencies were noted, including inadequate inspection procedures for the 'weight on wheels' sensors and insufficient guidance in the operator's maintenance manual regarding the installation and adjustment of landing gear components.
- The crew omitted the 'AUTOBRAKES (AS REQUIRED)' item during the landing checklist, failing to notice the system was still in the 'MAX' setting.