When should PCA be connected to an arriving aircraft?

Connecting the PCA (Pre-Conditioned Air) to an arriving aircraft should occur immediately after arrival. This practice is important for ensuring that passengers are comfortable as they deplane, especially in environments where outside temperatures could be extreme. By connecting PCA right after the aircraft has parked, the cabin can be climate-controlled, making it more pleasant for passengers disembarking from the aircraft.

This timing also aids in preventing the aircraft's systems from overworking in the event of extreme weather conditions. It ensures that environmental systems within the aircraft can operate more efficiently and that any necessary cabin depressurization or conditioning can occur smoothly.

Other options don't align with best practices because waiting until after refueling, before departure, or during the boarding process would delay the provision of comfortable conditions for the arriving passengers, which is a key objective in fleet service operations.