What happened
On 4 August 2001, an Airbus A320-111, registration F-GLGG, was undergoing a pushback maneuver from Stand F11 at London Heathrow Airport. The aircraft was being moved as part of a passenger flight involving 157 passengers and 6 crew members. During the operation, the pushback tug—an older model featuring a high cabin roof and a sliding door positioned across the longitudinal axis—was being operated with its cabin door open. This configuration increased the effective width of the tug's cabin.
As the pushback progressed, the angle between the tug and the aircraft's longitudinal axis became acute, positioning the upper corner of the open tug door directly beneath the aircraft's nose. While traversing a concrete joint on the apron, the aircraft's nose dipped momentarily. This movement caused the top corner of the tug's cabin door to strike the aircraft, resulting in a small dent and approximately 10 cm of scoring on the nose-cone skin. There were no injuries to the crew or passengers.
The investigation
The investigation examined the equipment and procedures used during the pushback. It was noted that the tow bar utilized for this specific maneuver was approximately 0.5 metres shorter than the standard tow bars maintained in the handling agent's inventory.
While the handling agent had previously conducted a risk assessment for the specific combination of the tug, tow bar, and aircraft, the investigation found that the assessment focused on clearance during standard movement. The potential for clearance to be compromised by vertical movement caused by uneven apron surfaces, such as concrete joints, had not been factored into the original risk evaluation.
Findings
- The primary cause of the contact was the aircraft nose dipping due to a bump in the apron surface.
- The use of an open cabin door on an older-model tug increased the width of the vehicle, reducing available clearance.
- The tow bar in use was significantly shorter than the agent's standard equipment.
- The existing risk assessment failed to account for the impact of apron surface irregularities on clearance margins.