An overhead join is a conventional method for an
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...
to approach and safely land at an airfield. It helps a pilot to integrate with any air traffic pattern near an
airfield
An aerodrome (Commonwealth English) or airdrome (American English) is a location from which aircraft flight operations take place, regardless of whether they involve air cargo, passengers, or neither, and regardless of whether it is for publ ...
, join any
circuit
Circuit may refer to:
Science and technology
Electrical engineering
* Electrical circuit, a complete electrical network with a closed-loop giving a return path for current
** Analog circuit, uses continuous signal levels
** Balanced circu ...
, 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
According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt concrete, as ...
is required. The overhead join is the standard method used in the
UK,
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...
and other
Commonwealth
A commonwealth is a traditional English term for a political community founded for the common good. Historically, it has been synonymous with " republic". The noun "commonwealth", meaning "public welfare, general good or advantage", dates from th ...
countries at smaller airports by
general aviation
General aviation (GA) is defined by the International Civil Aviation Organization (ICAO) as all civil aviation aircraft operations with the exception of commercial air transport or aerial work, which is defined as specialized aviation service ...
aircraft flying under the
visual flight rules
In aviation, visual flight rules (VFR) are a set of regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Specifically, the weather must be better ...
(VFR), and especially at airfields with no regular radio service.
Prior to arrival, the pilot might talk with
air traffic control
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airsp ...
(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. If the airfield is not equipped with ATC or radio, the pilot will establish these things before arrival by contacting the airfield prior to departure, or by using weather forecasts and the like.
This information is verified on arrival by overflying the airfield and looking out for the wind direction indications from a wind sock, smoke from fires, etc., or any ground signals in the signals square (if present). This involves positioning the aircraft so that it is flying across the direction of the runway and typically at 1000 feet higher than the circuit pattern for the airfield.
The pilot crosses the runway from the normal circuit for that runway, looking out for other traffic in the circuit, and descends to circuit height (often 1000 feet
AGL for GA aircraft or 500–600 feet for helicopters or at microlight airfields) on the ''dead side'' (opposite that of the normal circuit). With no traffic in circuit, the circuit is joined by crossing the upwind threshold and then turning downwind. With other traffic present in the circuit, the aircraft might be positioned downwind in the circuit behind or between other traffic in order to land in turn.
Alternatives to the overhead join are to directly join the circuit by entering at a suitable corner, or a straight-in approach. If available, ATC will negotiate with the pilot which is the most appropriate method according to the current traffic situation.
See also
Standard Overhead Join 3-D diagramStandard Overhead Joinposter reference
Air traffic control
Aircraft operations