What is an acceptable response when receiving an altitude request from another controller?

When receiving an altitude request from another controller, the response must clearly confirm the altitude and aircraft identification in a concise and standardized manner. The response "AAL121 at one five thousand (initials)" signifies that the flight AAL121 has been cleared to an altitude of 15,000 feet and is communicated directly and effectively, making it clear to the other controller what has been approved.

This format adheres to the common aviation communication standards by providing both the aircraft call sign and the specific altitude it is cleared to, ensuring that there is no ambiguity in the communication. Using the word "at" implies that the aircraft is now operating at that altitude, which is essential in ensuring that both controllers are on the same page regarding the aircraft's status and altitude clearance.

The other responses do not provide the same clarity or necessary information. For example, simply saying "approved" may not specify what is being approved, leaving potential room for confusion. Similarly, requesting confirmation or suggesting a change might imply uncertainty or a need for further clarification, which is not ideal in a standardized communication setting. Therefore, the selected response establishes a clear and effective communication protocol between controllers.