Which of the following is required for all aircraft operations in controlled airspace?

Communication with Air Traffic Control (ATC) is essential for all aircraft operations in controlled airspace. Controlled airspace is where air traffic control services are provided to manage the flow of air traffic and ensure safety. Therefore, maintaining communication with ATC allows pilots to receive important instructions, clearances, and traffic advisories, which are crucial for navigating and operating safely within this airspace.

In this regulated airspace, pilots must be in contact with ATC to ensure that their movements are coordinated with other aircraft, especially in busy urban areas or near major airports where traffic may be dense. This communication helps prevent collisions and allows for efficient traffic management.

While other options, such as flight plan submission or compliance with visual flight rules, might be applicable in certain circumstances or types of operations, they are not universally required for all operations within controlled airspace. For instance, not every flight needs to file a flight plan if it is operating under visual flight rules in uncontrolled airspace. Therefore, consistent communication with ATC stands out as the definitive requirement in controlled airspace operations.