Fix: A geographical position determined by reference to one or more NAVAIDS. A fix can be defined as
overhead the NAVAID, a radial and distance from the NAVAID, or a crossing point of two radials from two
Flight Level (FL): A surface of constant atmospheric pressure related to the standard pressure datum of
Flight Plan: Specified information relative to the intended flight of an aircraft provided to the cognizant air
traffic service unit.
Flight Service Station (FSS): A facility operated by the FAA to provide flight assistance service.
Ground Controlled Approach (GCA): A radar approach system whereby a controller interprets a radar
display and transmits approach instructions to the pilot to place the aircraft in a position for landing. The
approach may use surveillance radar (ASR) providing course and range information or precision approach
radar (PAR) providing course, range, and glideslope information. Do not request a GCA approach;
instead, you should specifically request either a PAR or an ASR approach.
HAA: See Height Above Airport.
HAT: See Height Above Touchdown.
Heading: The direction in which the longitudinal axis of the aircraft is pointed, usually expressed in
degrees from magnetic North.
Height Above Airport (HAA): Indicates the height of the MDA above the published airport elevation;
published in conjunction with circling minimums.
Height Above Touchdown (HAT): Indicates the height of the DH or MDA above the highest elevation in
the touchdown zone; published in conjunction with straight-in minimums.
Holding Fix: A specified fix used as a reference point to establish and maintain the position of an aircraft
Homing: Flight toward a NAVAID without correcting for wind by adjusting the aircraft heading to maintain
a relative bearing of zero degrees.