A final approach is the last leg in an aircraft's approach to landing. In aviation radio terminology, it is often abbreviated to "on final".
In a standard airport landing pattern, aircraft turn from base leg to final within one to two miles of the airport. For instrument approaches, as well as approaches into a controlled airfield under VFR, often a "straight-in" final approach is used, where all the other legs are dispensed with.
Approach slope
An approach slope is the path that an airplane 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 the topography and buildings. 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 this is technically incorrect, it is now a standard part of aviation talk. The technical incorrectness arises because an aircraft aiming for a perfectly failsafe landing or one that is landing without engine power will use its glide slope as its approach slope. However, in non-emergencies, approach slopes for non-gliders are usually shallower than the glide slope as this makes for a softer landing.
Final approach fix
The final approach fix is the point in space where the final approach begins in an instrument approach. The final approach fix is indicated when the aircraft crosses the outer marker of the airport's marker beacon. The location of the marker beacon varies from airport to airport, usually between 4 to 7 miles from the runway.
It is at this point in its forward flight that a landing aircraft should be established on the airport's Instrument Landing System (ILS) glideslope (the prescribed height above the terrain as the aircraft descends towards the runway) and localizer (which lines the aircraft up with the direction of the runway).
No comments:
Post a Comment