Incident Overview
On June 18, 2017, at approximately 21:48 local time, a Boeing 737-400 aircraft came to a stop while taxiing to a parking position at Warsaw Chopin Airport (EPWA). The aircraft was scheduled for another flight later that day. Due to Schengen-NonSchengen rotation requirements, the assigned parking stand was a remote position without a passenger boarding bridge.
Incident Details
The operator of a ground support equipment (GSE) set, consisting of a diesel tractor (type Mulag) and passenger stairs, parked the assembly between the green line marking the snow storage area and the service road line. This placement caused the GSE to intrude into the equipment restriction area (ERA) of the parking stand. As the aircraft was taxiing, the GSE obstructed the path, prompting the aircraft to stop. After the equipment was moved outside the ERA, the aircraft continued taxiing to its designated parking stand.
Cause
The cause of the incident was the incorrect positioning of the diesel tractor-passenger stairs assembly. The operator of the GSE set held valid training for operating the Mulag tractor and other GSE, as well as the necessary authorization to drive on the airport apron.
Safety Actions
Following the incident, the airport operator revoked the employee's authorization to operate motorized vehicles on the apron due to violations of the Operator's Procedures and the Airport Operations Manual. The employee underwent an explanatory and awareness meeting, was retrained on driving procedures at Warsaw Chopin Airport, and attended refresher training on GSE handling and equipment positioning during aircraft servicing. The principles of apron movement and obligations from the Airport Operations Manual have been incorporated into daily briefings with operational staff, including a detailed discussion of this incident and its consequences. The Polish State Commission on Aircraft Accident Investigation did not issue any safety recommendations.