This SAE Aerospace Standard describes the system used by passenger boarding stairs (PBS) mobile passenger boarding ramps (PBS) and boarding bridges (PBB) to inform on-board cabin crew about the docking status of the PBS/PBR/PBB and whether it is positioned such that it is safe to open the aircraft door.

Current practice calls for the PBS/PBR/PBB operator to knock on the aircraft door to inform the cabin crew that it is safe to open the aircraft door.

New technologies being incorporated into PBS/PBR/PBB such as remote control systems and autonomous driving vehicles are entering the market. As such, new/updated controls and/or procedures are necessary to ensure continuing safe operations.