What happened
On 28 June 2014, at London Stansted Airport, two Boeing 737-8AS aircraft were involved in a ground collision. The first aircraft, EI-ENL, was taxiing towards Stand 43R after arriving from Germany. Simultaneously, the second aircraft, EI-DLJ, was being pushed back from Stand 44R.
While the crew of EI-ENL was navigating the 'C West' line, the aircraft being pushed back, EI-DLJ, moved into its path. The right winglet of EI-ENL struck the right horizontal stabiliser of EI-DLJ. The impact was forceful enough to cause the winglet to detach and penetrate the APU bay of EI-DLJ, resulting in severe damage to the APU and a small fuel leak. There were no fatalities and no injuries to the crew or the hundreds of passengers on board both aircraft.
The investigation
The AAIB investigation examined ATC recordings, CCTV footage, and flight data from both aircraft. The investigation established that the Ground controller had issued a pushback clearance to EI-DLJ that conflicted with the taxi route previously assigned to EI-ENL. The controller had failed to notice the conflict on the electronic flight progress strips, possibly due to confusion between similar aircraft callsigns.
On the pushback team for EI-DLJ, a headset was unavailable, forcing the operator to use hand signals to communicate with the cockpit. This limited the operator's ability to monitor the area behind the aircraft. Furthermore, the pushback team lacked a guide person to check for hazards at the rear of the aircraft. The investigation also noted that the crew of EI-ENL did not identify the conflicting instructions on the radio frequency before the collision occurred.
Findings
- The primary cause was the issuance of conflicting ATC instructions that permitted a pushback into the path of a taxiing aircraft.
- The Ground controller's situational awareness was compromised by a lack of monitoring and the absence of an automated alert system for conflicting movements.
- The pushback team's effectiveness was reduced by the lack of a headset, necessitating non-standard hand signals, and the absence of a guide person.
- The geometry of the taxiway and the obscured view from the control tower contributed to the difficulty in detecting the hazard.