Missed approach is a procedure followed by a pilot when an instrument approach cannot be completed to a full-stop landing. The instructions for the missed approach may be assigned by air traffic control (ATC) prior to the clearance for the approach. If ATC has not issued specific instructions prior to the approach and a missed approach is executed, the pilot must follow the (default) missed approach procedure specified for the approach. Prior to commencing the approach, pilots can make a specific request to ATC if a missed approach may occur. Such a request may include heading and altitude instructions to avoid in-flight delays (such as holds) and efficiently maneuver the aircraft into position for either its next approach or a diversion to an alternate airport.