What happened
On 4 October 2023, a Boeing 737-8AS, registration EI-EGD, was taxiing to stand D62R at London Stansted Airport. The aircraft was operating with one engine shut down as it prepared to turn from a taxiway onto the apron stand. Simultaneously, a Bulmor SideBull OMNI 135 passenger assistance vehicle was travelling along the back-of-stand road, heading towards a different stand.
As the aircraft began its turn onto the stand, the vehicle continued along its path. Although the vehicle driver attempted an emergency stop and tried to reverse, the right wing leading edge of the Boeing 737-8AS struck the roof of the vehicle. There were no fatalities and no injuries to the 6 crew members or 103 passengers on board the aircraft.
The investigation
Investigators reviewed CCTV footage, aircraft flight data, and cockpit voice recordings. The analysis of the vehicle's internal monitoring system revealed that the driver's visual attention was primarily focused on the road ahead and searching for other vehicles or aircraft performing push-back manoeuvres. While the aircraft was visible through the vehicle's windows, the driver did not appear to notice the aircraft's movement onto the stand.
At the time of the collision, the flight crew was focused on the stand guidance system and preparing for parking. A ground handling agent at the head of the stand attempted to signal the pilots using hand signals, but the crew did not observe the signals. The investigation also noted that the driver had completed 13 tasks earlier that day and had expressed frustration regarding recent task assignments.
Findings
- The primary cause of the collision was that the vehicle driver failed to see the aircraft or failed to anticipate its turn onto the stand.
- The driver may have been experiencing inattentional blindness, a phenomenon where attention is so focused on specific stimuli (such as searching for push-back traffic) that highly visible objects are overlooked.
- The driver's performance may have been degraded by task-related fatigue and the high workload of a busy morning.
- The layout of the apron area created a high potential for conflict, as vehicles and aircraft can approach from multiple directions.
- The flight crew's attention was diverted by the requirements of the stand guidance system during the complex manoeuvre of turning with one engine shut down.