What is a key requirement for flight operations within controlled airspace?

In flight operations within controlled airspace, coordination with Air Traffic Control (ATC) is essential. This requirement ensures that the UAS pilot receives instructions and clearances necessary to operate safely in airspace where manned aircraft are also present. ATC manages the flow of air traffic, helping to prevent collisions and ensuring safe distance between aircraft. By coordinating with ATC, UAS operators can receive vital information, such as temporary flight restrictions or changes in traffic patterns, which are critical for maintaining a safe operational environment.

Other options may be relevant to certain situations or types of flying but do not address the specific necessity for operations in controlled airspace. Approval from local authorities could be needed for specific airspace permissions but does not replace the need for ATC coordination in controlled environments. Maintaining visual line of sight is primarily a requirement for safety, but it does not directly relate to the operational rules in controlled airspace. Flying only during daylight hours is a general operating limitation and does not pertain specifically to the operation within controlled airspace, as night operations can be conducted under certain conditions with proper authorization.