Event
On 23 February 2013, an Airbus A319-131 (registration G-EUOA) operated a commercial passenger flight from Basel to London Heathrow Airport. Upon arrival, the aircraft was directed to park at Stand 503. As the aircraft taxied onto the stand following the electronic guidance system, its left wingtip collided with a set of mobile steps that had been parked in the inter-stand clearway adjacent to the north end of Terminal 5. The steps were knocked over, landing on their side and protruding approximately five to six feet into the stand safety area. The flight crew, alerted by the Turn Round Manager (TRM), initiated an emergency stop. After assessing it was safe, the aircraft continued forward to its designated parking position without further incident. No injuries were reported among the 103 passengers or 6 crew members.
Investigation
The aircraft operator conducted an investigation and shared findings with the AAIB. It was established that the driver of the mobile steps had parked the vehicle at right angles to the aircraft's approach line with the engine running and steps raised. The vehicle was physically too large to park in that manner without infringing the sterile stand area, and it protruded into the safety area of Stand 503 by about 18 inches. The inter-stand clearway was determined to have a clearance of approximately 36 inches (0.925 m) between each wingtip and the edge for an A319 on the centreline.
The parked mobile steps vehicle was found to have a defective parking brake operating lever, which prevented full application of the brakes. Factors such as vehicle orientation and engine vibration could have caused the vehicle to move forward after being parked, contributing to its intrusion into the stand area.
The flight crew had assessed the stand as clear before taxiing, but were not aware of the relatively limited wingtip clearance at Heathrow's Terminal 5 stands.
Safety Actions
The aircraft operator implemented several safety actions to prevent recurrence. Ramp staff were reminded that vehicles must not be left unattended in inter-stand clearways, and a full walkaround inspection of the stand is required before aircraft arrival. Flight crews were reminded of the limited wingtip clearance at certain stands and airports, including Heathrow. Additionally, all ground equipment with parking brakes of the type fitted to the involved mobile steps were to be checked for similar defects and correct operation.
Based on the investigation, the airport operator's Operational Safety Instruction (OSI) 07/12 requires a nominated staff member to perform a safety check of the stand before aircraft arrival, ensuring it is free of vehicles, equipment, and foreign object debris. OSI/11/09 prohibits parking in inter-stand clearways and requires unattended vehicles to have engines off and brakes applied.