What is the appropriate response when AE64 calls Mayday over the radio?

When AE64 calls Mayday over the radio, the appropriate response is to acknowledge the distress call and confirm that the transmission has been received. Responding with "AE64, copy mayday standing by" indicates that the communication has been understood, and the responding party is prepared to assist or await further instructions. This response is crucial in emergency situations because it ensures that the distressed aircraft is aware that help is being mobilized, and that their safety is being prioritized.

Other responses may seem plausible but would not effectively address the urgency of the need for assistance. For instance, asking AE64 to repeat the message could delay vital support and is not appropriate when an emergency has already been established. Similarly, instructing AE64 to proceed to their next waypoint or maintain altitude does not directly address the Mayday call and could jeopardize their safety. In emergencies, clear and concise communication is vital, which makes the chosen response the most appropriate.