Final approach (aviation)
Encyclopedia
A final approach is the last leg in an aircraft's approach to landing. In aviation radio terminology, it is often shortened to "final".
In a standard airport landing pattern
, which is usually used under visual meteorological conditions
(VMC), aircraft turn from base leg to final within one to two miles of the airport. For instrument approach
es, as well as approaches into a controlled airfield under Visual flight rules
(VFR), often a "straight-in" final approach is used, where all the other legs are dispensed with. Straight in approaches are discouraged, but, allowed at non-towered airport
s as well.
follows on its final approach to land
on a runway
. It takes its name from the fact that this path is ideally a gentle downward slope
. A commonly used approach slope is 3° from the horizontal. However certain airports have steeper approach paths based on, topography, buildings, or other considerations. E.g., London UK City airport
has a 5.5° approach, and only aircraft that can maintain such an approach are permitted to use the airport.
The term glide slope is often applied to mean approach slope although to be correct it applies to the vertical guidance element of the Instrument Landing System
.
The final approach fix on an instrument approach
with vertical guidance is glide slope or glide path intercept at the lowest published altitude (USA), the same definition applies in ICAO except that this fix is called the final approach point. In the USA it is marked on a NACO IAP plate by a lightning bolt symbol and on a Jeppesen terminal chart by the end of the glide slope path symbol. It is the point in space where the final approach segment begins on the instrument approach. The final approach fix on a non-precision approach is marked by a Maltese cross symbol. If the approach navigation aid is on the field then there is no final approach fix, the aircraft becomes established on the final approach course once it is established inbound and this is called the final approach point (USA).
Airfield traffic pattern
An airfield traffic pattern is a standard path followed by aircraft when taking off or landing, while maintaining visual contact with the airfield....
, which is usually used under visual meteorological conditions
Visual meteorological conditions
In aviation, visual meteorological conditions is an aviation flight category in which visual flight rules flight is permitted—that is, conditions in which pilots have sufficient visibility to fly the aircraft maintaining visual separation from terrain and other aircraft. They are the opposite of...
(VMC), aircraft turn from base leg to final within one to two miles of the airport. For instrument approach
Instrument approach
For aircraft operating under instrument flight rules , an instrument approach or instrument approach procedure is a series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing, or to a point...
es, as well as approaches into a controlled airfield under Visual flight rules
Visual flight rules
Visual flight rules are a set of regulations which allow a pilot to operate 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 than basic VFR weather minimums, as specified in the rules of the...
(VFR), often a "straight-in" final approach is used, where all the other legs are dispensed with. Straight in approaches are discouraged, but, allowed at non-towered airport
Non-towered airport
A non-towered airport, sometimes referred to as an uncontrolled airport, is an airport with no operating tower, or air traffic control unit...
s as well.
Approach slope
An approach slope is the path that an airplaneFixed-wing aircraft
A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...
follows on its final approach to land
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
on a runway
Runway
According to ICAO a runway is a "defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft." Runways may be a man-made surface or a natural surface .- Orientation and dimensions :Runways are named by a number between 01 and 36, which is generally one tenth...
. It takes its name from the fact that this path is ideally a gentle downward slope
Slope
In mathematics, the slope or gradient of a line describes its steepness, incline, or grade. A higher slope value indicates a steeper incline....
. A commonly used approach slope is 3° from the horizontal. However certain airports have steeper approach paths based on, topography, buildings, or other considerations. E.g., London UK City airport
London City Airport
London City Airport is a single-runway airport. It principally serves the financial district of London and is located on a former Docklands site, east of the City of London, opposite the London Regatta Centre, in the London Borough of Newham in east London. It was developed by the engineering...
has a 5.5° approach, and only aircraft that can maintain such an approach are permitted to use the airport.
The term glide slope is often applied to mean approach slope although to be correct it applies to the vertical guidance element of the Instrument Landing System
Instrument Landing System
An instrument landing system is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument...
.
Final approach fix
Instrument approach
For aircraft operating under instrument flight rules , an instrument approach or instrument approach procedure is a series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing, or to a point...
with vertical guidance is glide slope or glide path intercept at the lowest published altitude (USA), the same definition applies in ICAO except that this fix is called the final approach point. In the USA it is marked on a NACO IAP plate by a lightning bolt symbol and on a Jeppesen terminal chart by the end of the glide slope path symbol. It is the point in space where the final approach segment begins on the instrument approach. The final approach fix on a non-precision approach is marked by a Maltese cross symbol. If the approach navigation aid is on the field then there is no final approach fix, the aircraft becomes established on the final approach course once it is established inbound and this is called the final approach point (USA).