What happened
On December 21, 2015, during ground handling operations at Katowice-Pyrzowice Airport (EPKT), an Airbus A320 was being prepared for pushback. As a Goldhofer AST 3 towbar tractor approached the aircraft, the operator noticed the nose wheels were slightly turned. The operator attempted to correct the positioning of the tractor several times but ultimately proceeded with the connection despite noting an axial misalignment of approximately 3 to 4 cm from the centerline of the nose gear.
As the operator began lifting the aircraft, the nose wheels straightened upon contact with the towbar's lower cradle. This movement caused the wheels to shift toward the right side of the aircraft, resulting in direct contact between the towbar components and the nose gear nut, which caused damage to the component. Upon realizing the towbar arms were incorrectly positioned, the operator requested the flight coordinator to inspect the connection. The coordinator discovered that the right towbar arm was protruding beyond the wheel rim and was too close to the gear, with one element of the nose gear scissor mechanism making contact with the towbar rollers.
The investigation
The investigation, conducted by the user's commission (ground handling agent), focused on the actions of the ground crew and the training protocols of the operator. The investigation established that the towbar operator was properly trained in theory but had not received practical training on the specific Goldhofer AST 3 model, having only practiced on an AM210 model. The operator reported experiencing significant stress and uncertainty due to this lack of experience.
Furthermore, the investigation examined the actions of the flight coordinator, who was managing multiple simultaneous tasks, including communicating with the pilot regarding taxiway clearance and engine start procedures for engine number 2, as well as disconnecting the Ground Power Unit (GPU).
Findings
- The primary cause of the incident was the improper practical training process for the towbar operator, which left them unqualified to operate the specific Goldhofer AST 3 unit.
- The towbar operator failed to adhere to established operating procedures by proceeding with the connection despite the misalignment.
- The flight coordinator failed to follow established procedures by not properly supervising the towbar connection process due to task saturation.
- The coordinator's physical position during the inspection prevented a clear view of the towbar mechanism closing.
- Insufficient lighting at the parking stand acted as a contributing factor to the incident.