Accident Overview
On 28 June 2014 at 0546 UTC, a collision occurred on the apron at London Stansted Airport involving two Boeing 737-8AS aircraft. The taxiing aircraft, EI-ENL (manufactured 2011, serial no. 35037), had its right winglet detached. The aircraft being pushed back, EI-DLJ (manufactured 2005, serial no. 34177), sustained damage to the right tailplane and severe damage to the APU installation. Both aircraft were operating commercial passenger flights. There were no injuries among the 6 crew and 161 passengers on EI-ENL, nor among the 6 crew and 178 passengers on EI-DLJ.
Sequence of Events
EI-ENL had landed on Runway 22 and was instructed by Ground control to proceed via the 'C West' line to park on Stand 43R. Meanwhile, EI-DLJ requested pushback from Stand 44R. The Ground controller approved the pushback onto the 'C West' line. The crew of EI-ENL did not recognize that the pushback instruction conflicted with their own routing. The pushback team for EI-DLJ used hand signals because no headset was available. The tug driver saw EI-ENL on Taxiway J but lost sight during pushback. As EI-ENL turned onto the 'C West' line, the co-pilot noticed the tail of EI-DLJ moving toward them and called for a stop. The commander began a left turn and applied brakes, but the right winglet of EI-ENL struck the leading edge of the right horizontal stabiliser of EI-DLJ 3.5 seconds later. The winglet penetrated the APU bay, causing fuel leakage. The tug driver braked but could not prevent the collision.
Post-Collision Response
After the collision, EI-ENL stopped a few meters further on. The controller initiated Aircraft Ground Incident procedures after an Operations vehicle declared an emergency. Fire services arrived within two minutes. Both aircraft were later towed to their stands, and all occupants disembarked without injury. The commander of EI-DLJ made a public address instructing passengers to remain seated. The crew of EI-ENL started the APU and also instructed passengers to stay seated. Fire services upgraded the incident to an accident, prompting an enhanced emergency response.
Investigation Findings
Recorded data from the Flight Data Recorder and Cockpit Voice Recorder of EI-ENL, as well as CCTV footage, were used to reconstruct the event. The maximum groundspeed of EI-ENL was just under 30 kt, reducing to about 10 kt at the start of the turn. The pushback commenced as EI-ENL began the turn. The APU on EI-DLJ failed upon impact. The CVR on EI-DLJ stopped when electrical power was lost. The controller's view of the stands was obscured by a pier. Safety actions were taken by the operator, air traffic control agency, regulator, and ground handling company; therefore, no AAIB Safety Recommendations were issued.