What happened
On 24 November 2013, a Boeing 757-200 operated by US Airways was undergoing pushback and towing operations at Brussels Airport. After being towed to position 210, the ramp operator instructed the flight crew to set the aircraft brakes. Following this, the pilot authorized the disconnection of the steering by-post pin and the headset cable.
As the ramp operator walked back toward the Goldhofer towbarless tug, the aircraft engines began to spool up, and the aircraft started moving forward. The operator attempted to signal the crew to stop, but the nose gear of the Boeing 757-200 struck the lifting mechanism of the tug. The impact propelled the tug forward several meters before the aircraft came to an abrupt halt. While the passengers were unharmed, the collision caused some cabin crew to be slightly injured when they were jolted during the impact.
The investigation
An investigation by AAIU(Be) focused on the sequence of events and the visibility of the ground equipment. Investigators found that the cabin of the towbarless tug was positioned such that it was obscured from the pilots' view by the aircraft's nose. Although the tug's amber lights were active, they were not visible to the crew due to the daylight and the aircraft's fuselage obstructing the line of sight.
The investigation also examined the communication protocols between the ground handler, Swissport, and the flight crew. It was noted that the flight crew's checklist involved verifying that the wings were clear, but they lacked a definitive visual cue from the ground operator to signal that the area was safe for taxiing. Furthermore, the crew's familiarity with single-operator pushback procedures was scrutinized, as they had initiated movement without receiving a clear 'OK-to-taxi' hand signal.
Findings
- The primary cause of the collision was the aircraft starting to taxi before the pushback procedure was completed.
- A lack of visible cues from the ground operator to the flight crew contributed to the incident.
- Procedures between the ground handler and the airline were not harmonized, specifically regarding the transition from disconnection to taxiing.
- The physical positioning of the towbarless tug created a blind spot for the flight crew.