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 airspace. The primary purpose of ATC worldwide is to prevent collisions, organize and expedite the flow of air traffic, and provide information and other support for pilots. In some countries, ATC plays a security or defensive role, or is operated by the military.
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 or a natural surface. Runways, as well as taxiways and ramps, are sometimes referred to as "tarmac", though very few runways are built using tarmac. Takeoff and landing areas defined on the surface of water for seaplanes are generally referred to as waterways. Runway lengths are now commonly given in meters worldwide, except in North America where feet are commonly used.
In aviation, the instrument landing system (ILS) is a radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. In its original form, it allows an aircraft to approach until it is 200 feet (61 m) over the ground, within a 1⁄2 mile (800 m) of the runway. At that point the runway should be visible to the pilot; if it is not, they perform a missed approach. Bringing the aircraft this close to the runway dramatically improves the weather conditions in which a safe landing can be made. Later versions of the system, or "categories", have further reduced the minimum altitudes.
The Pacific Missile Range Facility, Barking Sands is a U.S. naval facility and airport located five nautical miles (9 km) northwest of the central business district of Kekaha, in Kauai County, Hawaii, United States.
The Wide Area Augmentation System (WAAS) is an air navigation aid developed by the Federal Aviation Administration to augment the Global Positioning System (GPS), with the goal of improving its accuracy, integrity, and availability. Essentially, WAAS is intended to enable aircraft to rely on GPS for all phases of flight, including precision approaches to any airport within its coverage area. It may be further enhanced with the Local Area Augmentation System (LAAS) also known by the preferred ICAO term Ground-Based Augmentation System (GBAS) in critical areas.
An instrument landing system localizer, or simply localizer (LOC), is a system of horizontal guidance in the instrument landing system, which is used to guide aircraft along the axis of the runway.
In aviation, an instrument approach or instrument approach procedure (IAP) is a series of predetermined maneuvers for the orderly transfer of an aircraft operating under instrument flight rules from the beginning of the initial approach to a landing or to a point from which a landing may be made visually. These approaches are approved in the European Union by EASA and the respective country authorities and in the United States by the FAA or the United States Department of Defense for the military. The ICAO defines an instrument approach as a series of predetermined maneuvers by reference to flight instruments with specific protection from obstacles from the initial approach fix, or where applicable, from the beginning of a defined arrival route to a point from which a landing can be completed and thereafter, if landing is not completed, to a position at which holding or enroute obstacle clearance criteria apply.
In aviation, autoland describes a system that fully automates the landing procedure of an aircraft's flight, with the flight crew supervising the process. Such systems enable airliners to land in weather conditions that would otherwise be dangerous or impossible to operate in.
A blind approach beacon system or beam approach beacon system (BABS) is an automatic radar landing system developed in the early 1940s.
The microwave landing system (MLS) is an all-weather, precision radio guidance system intended to be installed at large airports to assist aircraft in landing, including 'blind landings'. MLS enables an approaching aircraft to determine when it is aligned with the destination runway and on the correct glidepath for a safe landing. MLS was intended to replace or supplement the instrument landing systems (ILS). MLS has a number of operational advantages over ILS, including a wider selection of channels to avoid interference with nearby installations, excellent performance in all weather, a small "footprint" at the airports, and wide vertical and horizontal "capture" angles that allowed approaches from wider areas around the airport.
Precision approach radar (PAR) is a type of radar guidance system designed to provide lateral and vertical guidance to an aircraft pilot for landing, until the landing threshold is reached. Controllers monitoring the PAR displays observe each aircraft's position and issue instructions to the pilot that keep the aircraft on course and glidepath during final approach. After the aircraft reaches the decision height (DH) or decision altitude (DA), further guidance is advisory only. The overall concept is known as ground-controlled approach (GCA), and this name was also used to refer to the radar systems in the early days of its development.
A transponder landing system (TLS) is an all-weather, precision landing system that uses existing airborne transponder and instrument landing system (ILS) equipment to create a precision approach at a location where an ILS would normally not be available.
Required navigation performance (RNP) is a type of performance-based navigation (PBN) that allows an aircraft to fly a specific path between two 3D-defined points in space.
Perth Airport is a general-aviation airport located at New Scone, 3 nautical miles northeast of Perth, Scotland. The airport is used by private and business aircraft, and for pilot training. There are no commercial scheduled flights from the airport.
An approach lighting system (ALS) is a lighting system installed on the approach end of an airport runway and consisting of a series of lightbars, strobe lights, or a combination of the two that extends outward from the runway end. ALS usually serves a runway that has an instrument approach procedure (IAP) associated with it and allows the pilot to visually identify the runway environment and align the aircraft with the runway upon arriving at a prescribed point on an approach.
In aviation a ground-controlled approach (GCA), is a type of service provided by air-traffic controllers whereby they guide aircraft to a safe landing, including in adverse weather conditions, based on primary radar images. Most commonly a GCA uses information from either a Precision Approach Radar or an Airport Surveillance Radar. The term GCA may refer to any type of ground radar guided approach such as a PAR, PAR without glideslope or ASR. When both vertical and horizontal guidance from the PAR is given, the approach is termed a precision approach. If no PAR glidepath is given, even if PAR equipment is used for lateral guidance, it is considered a non-precision approach.
A localizer type directional aid (LDA) or Instrument Guidance System (IGS) is a type of localizer-based instrument approach to an airport. It is used in places where, due to terrain and other factors, the localizer antenna array is not aligned with the runway it serves. In these cases, the localizer antenna array may be offset in such a way that the approach course it projects no longer lies along the extended runway centerline. If the angle of offset is three degrees or less, the facility is classified as an offset localizer. If the offset angle is greater than three degrees, the facility is classified as a localizer-type directional aid (LDA). Straight-in approaches may be published if the offset angle does not exceed 30 degrees. Only circling minimums are published for offset angles greater than 30 degrees. As a "directional aid", and only a Category I approach, rather than a full-fledged instrument landing system (ILS), the LDA is more commonly used to help the pilot safely reach a point near the runway environs, where he or she hopefully can see the runway, at which point he or she will proceed and land visually, as opposed to full Category III ILS systems that allow a pilot to fly, without visual references, very close to the runway surface depending on the exact equipment in the aircraft and on the ground.
The AN/MPN is a mobile Ground-controlled approach radar first used during World War II. "MPN" is Joint Electronics Type Designation System nomenclature for (Ground) Mobile (M), Pulsed (P), Navigation aid (N).
Wide area multilateration (WAM) is a cooperative aircraft surveillance technology based on the same time difference of arrival principle that is used on an airport surface. WAM is a technique where several ground receiving stations listen to signals transmitted from an aircraft; then the aircraft's location is mathematically calculated -- typically in two dimensions, with the aircraft providing its altitude. Aircraft position, altitude and other data are ultimately transmitted, through an Air Traffic Control automation system, to screens viewed by air traffic controllers for separation of aircraft. It can and has been interfaced to terminal or en-route automation systems.
An enhanced flight vision system is an airborne system which provides an image of the scene and displays it to the pilot, in order to provide an image in which the scene and objects in it can be better detected. In other words, an EFVS is a system which provides the pilot with an image which is better than unaided human vision. An EFVS includes imaging sensors such as a color camera, infrared camera or radar, and typically a display for the pilot, which can be a head-mounted display or head-up display. An EFVS may be combined with a synthetic vision system to create a combined vision system.
