When at a controlled airport, what must a pilot do before proceeding?

In a controlled airport environment, obtaining clearance is an essential procedure that ensures the safety and coordination of aircraft movements on the ground and in the airspace. When a pilot proceeds without clearance, it can lead to unauthorized movements that may conflict with other aircraft or airport operations, thus increasing the risk of accidents.

Pilots are required to communicate with air traffic control (ATC) before taxiing, taking off, or landing to receive clearance that confirms they have permission to execute these movements safely. This process is designed to manage traffic efficiently and to maintain safe separation between aircraft within the controlled airspace.

While other options may involve important procedures, they do not fulfill the fundamental requirement of receiving clearance from ATC, which is a crucial step for ensuring operational safety at controlled airports.