What happened
During the arrival of an aircraft, ground personnel from another operator marshalled the plane onto a stop bar designated for a 727. This stop bar was located approximately 25 feet forward of the standard 737 stop bar line. Once the aircraft was parked, the loading bridge operator moved the bridge toward the plane. During this maneuver, the loading bridge impacted the aircraft's left engine pylon fairing. At the time of the impact, the wheels of the loading bridge were positioned within the painted hash-mark box.
The investigation
The investigation into the ground operations revealed that the Supervisor on Duty had specifically directed the marshaller to bring the aircraft to the 727 stop block, which is roughly 25 to 30 feet ahead of the 737 stop block. This instruction was only communicated to the marshaller and was not shared with other personnel involved in the arrival. Additionally, the supervisor was not present during the aircraft's arrival. The ground personnel involved typically handle regional jets, making the marshalling of this specific flight an irregular operation for them.