When receiving an approach clearance while radar vectored, what altitude should be maintained?

When receiving an approach clearance while being radar vectored, the pilot should maintain the altitude until established on a published route or approach procedure. This is because the purpose of maintaining this altitude is to ensure safe separation from other aircraft and terrain while following the controller's instructions during the transition to the approach. Being established means that you are correctly aligned and following the course of the approach as per air traffic control guidance.

Maintaining altitude until established ensures that pilots do not inadvertently descend too early or deviate off the prescribed approach path which can lead to safety concerns. In most cases, the controller will guide you to the final approach course through radar vectors, and only when you have successfully intercepted and are on the published route should you begin any descent procedures in accordance with the approach protocol.

While other options may imply different methods of altitude management, they do not align with the standard procedure as outlined in aeronautical regulations and guidelines. For instance, waiting until the final approach fix or until advised by the controller does not provide a clear framework for maintaining safe altitude management throughout the approach sequence. Similarly, remaining at a specific holding altitude may not always be applicable during radar vectors unless instructed by ATC.