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 approaches, 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 airports as well.[1]
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, 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).[2]