What happened
On July 23, 2015, an incident occurred at Bydlarsczka (EPBY) airport during the pushback of a Boeing 737-800 from parking stand number 3. While the aircraft was being pushed from its position, the pushback tug driver executed a turn to the left that was too sharp. During this maneuver, an alarm light indicating the disconnection of the nose gear strut activated within the tug vehicle.
In an attempt to address the alarm, the operator disconnected the aircraft's nose gear from the tug. This action caused the tug's wheel to become jammed against the aircraft's landing gear door. As a result of the maneuver, the nose gear strut was twisted by 90 degrees. Following an assessment of the damage, the captain decided to disembark all passengers, and the scheduled flight was subsequently completed using a replacement aircraft.
The investigation
The investigation, conducted by Bydgoszcz Airport S.A., focused on the actions of the tug operator and the operational environment at the ramp. The investigators examined the operator's training history, the physical constraints of the parking stand, and the existing ground handling procedures at the airport.
Findings
- The primary cause of the incident was the lack of experience of the pushback vehicle operator, who had only completed the required training in 2013 and had not performed any aircraft pushbacks since that time.
- The maneuver at parking stand number 3 is inherently difficult, requiring three separate turns of up to 90 degrees within a very confined space.
- There was a lack of timely reaction from the Ramp Supervisor during the event.
- A recent regulatory change required a minimum number of monthly pushbacks for all operators regardless of experience, yet there was no system in place to monitor the actual number of pushbacks performed by individual operators.
- Operational challenges included frequent changes to technical staff schedules.
- The airport's pushback and towing procedures lacked a specific description of the 'OVERTORQUE' alarm function and the necessary corrective actions to be taken upon its activation.