It helps a pilot to integrate with any air traffic pattern near an airfield, join any circuit, and land.
Aircraft may arrive at the landing site from any direction, so a safe means of integrating into existing traffic and aligning with the runway is required.
The overhead join is the standard method used in the UK, South Africa and other Commonwealth countries at smaller airports by general aviation aircraft flying under the visual flight rules (VFR), and especially at airfields with no regular radio service.
Prior to arrival, the pilot might talk with air traffic control (ATC) over the radio to establish the runway in use, the circuit height and direction (left or right hand), and the QFE (atmospheric pressure) of the field.
This involves positioning the aircraft so that it is flying across the direction of the runway and typically at 300 m (1,000 ft) higher than the circuit pattern for the airfield.