What is the term for the clearance given to an aircraft to execute an instrument approach?

The term for the clearance given to an aircraft to execute an instrument approach is approach clearance. This clearance is crucial as it authorizes the pilot to proceed with the approach to the runway, following the specified procedures that guide the aircraft down to a safe landing. The issuance of an approach clearance signifies that air traffic control has ensured the necessary spacing and safety of other aircraft in the system, allowing for a structured and safe execution of the approach.

In contrast, landing clearance is specifically granted when the aircraft is cleared to land on the runway, which occurs after the approach clearance has already been given and executed. Final approach instruction relates more to the guidance provided during the last segment of the approach, while takeoff clearance is entirely different, as it pertains to the authorization for an aircraft to take off from the runway. Each of these terms denotes a specific phase of flight operations and has its own unique procedures and implications in aviation.