What happened
On 10 January 2006, a Boeing 777-236, registration G-ZZZC, was being prepared for departure from Stand 422 at London Heathrow Airport. Due to the specific layout of the stand, the pushback required a non-standard procedure involving a turn onto the taxiway centerline and a subsequent reversal of the turn.
During the maneuver, the aircraft's left wingtip made contact with the right winglet of a parked Boeing 747-400. The collision resulted in minor damage to the G-ZZZC left wingtip, including damage to the navigation light assembly and three static discharge wicks. There were no injuries to the 14 crew members or 106 passengers on board.
The investigation
The investigation established that the pushback team was operating with only one wing/tail observer instead of the required two due to staffing shortages. While the towbarless tractor driver and headset operator had identified cargo containers and dollies at the edge of the stand, they had determined these items did not pose a direct hazard to the aircraft.
However, the third team member, the wing tip observer, arrived at the stand just as the pushback was commencing. As this observer moved to his position, he had to navigate around the parked cargo equipment. This movement caused a momentary distraction from his primary duty of monitoring clearance. Although the observer eventually signaled the driver to stop, the signal was either not seen or not received in time to prevent the collision.
Findings
- The primary cause of the collision was the driver's initial over-steering, which placed the aircraft on a path toward the parked Boeing 747-400.
- The presence of cargo containers and dollies in the observer's path distracted the wing tip observer from monitoring clearance.
- The wing tip observer's movement around the equipment temporarily obstructed his line of sight to the driver.
- Staffing shortages resulted in an insufficient number of observers for the complex pushback maneuver.