T-6A INSTRUMENT NAVIGATION
Failure to recognize deviation from glideslope and direct the appropriate correction.
509. GROUND CONTROLLED APPROACH
GCAs use radar to vector the aircraft to a position for landing during conditions of low ceiling
and/or poor visibility. There are 2 types of approaches: PAR and ASR. The PAR provides the
pilot with precise course, glideslope, and range information; the ASR provides course and range
information and is classified as a non-precision approach. Upon request, for ASR approaches,
the controller will provide recommended altitudes on final to the last whole mile that is at or
above the published MDA.
Radar instrument approach minimums are published in the front of the FLIP terminal IAPs
(approach plates). PAR minimums may also be found in the minimum section of approach
plates, if PAR approaches are available. You should always reference the radar instrument
approach minimums in the front first. Published information includes the DH, weather
minimums, and glideslope angle. By comparing glideslope and GS, the pilot can determine
vertical speed required to maintain glideslope on final. For example, a 3° glideslope and a GS of
120 KIAS will result in a vertical speed of 600 FPM on the VSI (glideslope x miles per minute =
VSI). This math is already done for you. If you look on the last page (inside of the back cover)
of the approach plate, you will find a chart depicting required rate of climb/descent.
Figure 5-20 is a sample of the section in the approach plates that contains information on radar
approaches. For the purposes of illustration, we will consider the PAR approach to runway 5 at
APPROACH PLATE REVIEW
1. Radar - A list of frequencies and referenced notes. The notes in reference can be found at
the bottom of the minimums section. The Xs following the frequencies indicate ATC has the
capability to work on that frequency but does not monitor it continuously.
RWY - Runaway plus any referenced notes.
Glideslope - Glideslope of 3º.
4. Threshold Crossing Height (TCH) is 39 feet. This means that if you are on glideslope, as
you cross the runway threshold, you will be 39 feet above the runway surface.
5. Runway Point of Intercept (RPI) is 736 feet. If you remain on glideslope until
touchdown, you will land 736 feet down the runway.
6. Category of Aircraft (CAT) - "ABCDE" indicates the published minimums for this
approach applies to all five categories of aircraft.
7. DH, MDAVIS (Visibility) - The DH is 114 feet MSL. Minimum visibility required for
this approach is 1/2 mile.