What happened
On 2 November 2002, a Boeing 737-8AS, registration EI-CSM, was parked nose-in at the satellite terminal stand D62R at London-Stansted Airport. The aircraft was prepared for a scheduled public transport flight to Trieste, Italy, with 136 passengers and 5 crew members on board. The aircraft doors had been closed and the flight was ready for departure.
During this period, a ground driver returned to the stand to relocate a tug. Although the driver intended to disconnect a set of steps from the tug, the two remained attached. The driver proceeded to drive the combination across the stand rather than using the designated inter-stand clearway. Unaware that the steps were still connected, the driver drove underneath the right wingtip of the aircraft. The top of the steps struck the number eight slat, causing significant damage to the wing structure.
Inside the cockpit, the commander experienced a violent sideways movement and a rocking motion of the aircraft nose. Initially suspecting a collision with another aircraft, the commander inspected the terminal windows for reflections of nearby planes. Upon noticing liquid leaking from the right wingtip, the commander consulted with a ground engineer, who confirmed the liquid was water from wing surface accumulation rather than fuel. As a precaution, the APU was shut down and ground power was connected.
The investigation
The investigation established that the collision occurred because the driver failed to ensure the steps were disconnected from the tug before moving the vehicle. Furthermore, the driver deviated from the required transit path, driving across the stand instead of following the established clearway. Following the impact, the aircraft was withdrawn from service for necessary repairs, and the passengers were evacuated via the standard exit without injury.