Final answer:
An AVOP is a permit that authorizes individuals to operate vehicles on the apron and taxiways of an airport, and a controlled taxiway refers to a taxiway under the control of ATC. Only vehicles operated by or escorted by a D AVOP holder can enter or cross a controlled taxiway, with clearance from ATC being mandatory.
Step-by-step explanation:
An AVOP (Apron Vehicle Operator Permit) is a credential issued by an airport authority to authorize individuals to operate vehicles on the apron and taxiways of an airport. In the given context, a controlled taxiway refers to a taxiway that is under the control of Air Traffic Control (ATC).
Only vehicles operated by or escorted by an individual holding a D AVOP (Driver Apron Vehicle Operator Permit) are allowed to enter or cross a controlled taxiway. It is mandatory to obtain clearance from ATC before entering or crossing a controlled taxiway to ensure safety and proper coordination.
By implementing these restrictions, airports can regulate access to controlled taxiways and maintain the efficient flow of aircraft and ground vehicles, minimizing the risk of accidents or incidents.