The runway (RWY), plus any referenced notes.
The PAR approach to runway has a glideslope (GS), of 3º.
The 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
Runway point of intercept (RPI). If you remain on glideslope until touchdown, you
will land 736 feet down the runway.
Category of aircraft (CAT). "ABCDE" indicates that the published minimums for
this approach applies to all five categories of aircraft.
Decision Height (DH), Minimum Descent Altitude (MDA) is the MSL altitude of
114 feet in this case. Minimum visibility required for this approach is ½ mile.
Runway Visibility Range (RVR) may be listed if used.
Height above touchdown (HAT) and Height above airport (HAA) is the AGL
altitude of the published (DH) or (MDA).
CeilingVisibility, (CEILVIS), is used during filing to determine alternate
The T34C is considered a singlepiloted aircraft. OPNAV requires
that singlepiloted aircraft use 200 feet ceiling/HAT and ½ mile/
2400 feet RVR as absolute minimums for Instruments approaches.
Consider the above example. When you reached the published
decision height of 114 feet MSL, you will be at an HAT of 100 feet
AGL. In order not to break the 200 feet HAT absolute minimum,
you must increase the decision height. In this case, an increase of
100 feet is necessary. This would result in a modified DH of 214
feet MSL resulting in a HAT of 200 feet AGL. In addition, the
minimum visibility required to commence the approach would
become ½ mile instead of the ¼ mile, had that been the case.
6-118 RADIO INSTRUMENT FLIGHT PROCEDURES