(e)
The data received and transmitted between the FMC and IRS is low speed digital data.
(19) Automatic Direction Finder (ADF) (Fig. 15)
(a) The FMC transmits a frequency, to be tuned by the ADF, via the master FMC master switching relays. This commanded frequency can be manually tuned by the crew or automatically tuned through data contained in the NDB. The frequency command will be sent over a low speed ditigal bus.
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(20)
Distance Measuring Equipment (DME) (Fig. 15)
(a) The FMC receives distance and frequency data from both left and right DMEs. The FMC also sends a commanded tuning frequency to each DME via the FMC master switch relays. The DME is capable of automatically tuning 252 frequencies, five of these tuned frequencies will be used by the FMC for VHF NAV radio position updating. The FMC will control the tuning of these five frequencies as well as control the allocation of the DME data for the five tuned navaids. This is explained further in the navigation function section.
(21)
VHF Omnidirectional Receivers (VOR) (Fig. 15)
(a) VOR receivers are used for VHF NAV radio positioning. The FMC receives bearing and frequency data from both the left and right VORs for navigation purposes. The FMC transmits a commanded tuning frequency via the FMC master switch relays. The data transmitted and received will be over low speed digital busses.
(22)
Instrument Landing System (ILS) (Fig. 15)
(a) The ILS is used for VHF NAV radio positioning during approach only. The data received from both left and right ILSs is glideslope deviation, ILS frequency and localizer deviation. The FMC will control the tuning by sending a frequency command to the ILS via the FMC master switch relays. The data transmitted and received will be sent over a low speed digital bus.
(23)
Flight Control Computer (FCC) (Fig. 16)
(a)
The FMC transmits data pertaining to airplane control. This data consists of the following: 1) FMC discretes 2) Horizontal steering 3) Selected altitude 4) Selected airspeed 5) Selected mach 6) Vertical steering rate 7) Vertical steering
(b)
The FCC uses these low speed digital signals to control pitch and roll of the airplane. The FCC also send ILS tune inhibit signals to the FMC. These tune inhibit signals are analog input discretes for all three, left, right and center ILS.
(24)
Automatic Flight Director System Control Panel (AFDS CP) (Fig. 16)
(a) The AFDS CP transmits pilot entered selections on the control panel. This pilot selected data consists of the following: 1) AFCS mode status 2) AFCS request modes 3) Altitude selected 4) Elevation speed command 5) Flap position 6) Flare retard rate 7) Heading selected 8) Mach selected 9) Speed break handle position
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10) Speed selected
11) Stabilizer position
12) Vertical speed selected
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