When does MARSA between tankers and receiver aircraft begin?

MARSA, which stands for Military Assumption of Risk in the Separation of Aircraft, begins when the tanker and receiver aircraft enter the refueling airspace and the tanker advises Air Traffic Control (ATC). This point marks the transition into a controlled environment where the military assets take responsibility for separation and safety rather than relying solely on ATC.

At this stage, both aircraft are recognized as engaged in the refueling operation, and any required safety protocols can take precedence over standard civilian air traffic rules. The communication with ATC is crucial at this point because it notifies them of the operation and helps ensure that surrounding air traffic is adequately managed.

Understanding this context clarifies why the other options do not accurately describe the start of MARSA. For instance, synchronization of fuel levels or reaching the rendezvous point does not define the operational area and responsibility transfer. Completing refueling maneuvers would signify the end of that operation, rather than the initiation of MARSA.