Marker Beacons (Fan Markers)

APPENDIX F

INTERMEDIATE FLIGHT PREPARATION WORKBOOK

Gulfport), then you will have to select the TACAN channel, the ILS frequency, and TCN/LOC.

VOR/LOC will give you ILS and ILS-DME information, TCN/LOC will give ILS and TACAN-

DME information.

F104. MARKER BEACONS (FAN MARKERS)

Marker beacons are available with some ILS/localizer systems. Ordinarily there are 2 marker

beacons associated with an ILS: the Outer Marker (OM) and the Middle Marker (MM). The

OM always transmits at 400 Hz, and is indicated with an aural signal and an "OM" flashing on

the Attitude Directional Indicator (ADI) (or a flashing "blue" light on some aircraft). The OM is

collocated with the FAF and the approximate position for glideslope interception. The MM

always transmits at 1300 Hz, is collocated with the MAP or DH, and is indicated by an aural tone

and the "MM" flashing on the ADI (or a flashing "amber" light on some aircraft). Simply pull

the marker beacon knob(s) on the comm panel (see Dash-1, pg. 1-354) and make sure the volume

is at least halfway, no frequency input is necessary.

F105. COMPASS LOCATORS

A compass locator is a Nondirectional Beacon (NDB) used in conjunction with, or in place of a

MM and/or OM. They are tuned up on the ADF (see Mobile Regional ILS 14). You will need to

select the ADF on the bearing needle on the DSP. Upon station passage it will swing from 12 to

6 o'clock.

F106. TIMED ILS

As a backup, a timing box near the bottom of an approach plate will give the time required to

travel from the OM (FAF) to the MM (DH/MAP).

F107. SET UP

While initiating the "Approach brief" on the Descent Checklist, the ILS frequency should be

entered in NAV 1 and 2 (unless one of the NAVs need to be used for a radial to define the

OM/MM - see ILS 17 at Pensacola Regional. Saufley is used to define the FAF). Select

VOR/LOC or TCN/LOC (see Dash-1 pg. 1-194). Select the marker beacon (you can select 1 or 2

or both) and compass locator, if available. Zeroize your clock and be ready to start it passing the

OM/FAF. Initiate landing checks between 8-10 DME or between 1 to 2 dots below glideslope

(see Dash-1, pg. 1-174).

For more on the ILS/localizer system, refer to the AIM (a copy is located in the Ready Room).

Your instructor will brief and assist you with your first ILS approach, but you must still function

as a crewmember, so try to do as much as you can on your own. If you have any questions,

contact your PA, any T-1 instructor or P.

F-2 INSTRUMENT LANDING SYSTEM (ILS) BASIC