INSTRUMENT FLIGHT RULES WORKBOOK
305. NONPRECISION APPROACHES
A nonprecision approach provides directional (azimuth) guidance only; altitude restrictions are
listed in the approach procedure (FLIP Low Altitude Approach Plates). The pilot flies the
aircraft along the depicted or directed course, keeping the aircraft within the published altitude
restrictions as it descends toward the airport. Nonprecision approaches may be based upon
VOR, VOR/DME, TACAN, NDB, GPS, or Localizer radio aids, or upon communications from a
306. ASR APPROACH
The ASR approach is a nonprecision radar ground controlled approach. During an ASR
approach, the radar controller will provide the pilot with azimuth information in the form of
headings to fly. All altitude information will be advisory. The controller will state, if the pilot
requests, the recommended altitude at each mile of the approach.
The ASR ground controlled approach also requires two-way radio communications and cannot
be used for selection of an alternate airport for single-piloted aircraft
An example of the controller's instruction would be:
"ON COURSE, TWO MILES FROM RUNWAY, ALTITUDE SHOULD BE ONE
THOUSAND EIGHT HUNDRED FEET."
307. LOCALIZER APPROACH
A localizer (LOC) approach is a nonprecision approach using the ILS localizer for course
guidance (no glidepath information is provided). To execute a LOC approach, an aircraft must
be equipped with a VHF navigation receiver able to receive the LOC frequency range of 108.1 to
111.9 MHz. LOC frequencies will always end in odd tenths. When executing a LOC approach
the CDI is used to display course information.
With a localizer frequency tuned the CDI becomes four times more sensitive, displaying .5º per
mark instead of 2º. Additionally, the OBS knob has no effect on CDI movement and the
TO/FROM flag disappears from view. The VOR needle will freeze at the 3 o'clock position.
Additional navigation equipment (LF/MF ADF, marker beacon, or DME) is required for the pilot
to know the distance from the runway. A Localizer approach may be executed when the Initial
Approach Fix, Final Approach Fix, and Missed Approach Point can be identified. Approach
Control can use radar to assist in determining these fixes during practice approaches.
NDB (Non-directional Beacon) approaches are published for both LF/MF and UHF Non-
directional Radio Beacons. The T34C is not equipped to receive either type of signal, and
therefore cannot execute either approach.
INSTRUMENT APPROACH PROCEDURES 3-7