Before entering controlled airspace, what must an aircraft obtain?

• A. Approval from ground crew
• B. Weather clearance
• C. Prior clearance from ATC
• D. Transponder activation

Answer: (C)

An aircraft must obtain prior clearance from Air Traffic Control (ATC) before entering controlled airspace to ensure safety and organization within the national airspace system. This clearance is essential because controlled airspace has specific regulations and procedures that govern aircraft operations, including requirements for separation from other aircraft, communication protocols, and altitude restrictions. The ATC provides instructions related to these factors to maintain safe and efficient air traffic flow.

Other factors like weather clearance and transponder activation may be relevant for specific types of flights or circumstances, but they do not directly address the need for obtaining permission to enter controlled airspace. Ground crew approval is generally not a requirement for airspace entry; rather, it pertains more to operational readiness and pre-flight checks. Thus, gaining prior clearance from ATC is paramount in ensuring the safety and compliance with airspace regulations.