Description (AMM 34-31-02)

 

A.- Two coaxial relays are installed on shelf No. 4 of electronic equipment rack E3 in the main equipment center. The relays are energized by mode logic in the DFCS when the associated navigation unit is tuned to an ILS frequency. The logic requires that an ILS frequency be tuned; DFCS approach or VOR/LOC mode must be selected; and either VOR/LOC arm or VOR/LOC engage logic available in the associated DFCS flight computer.

 

The relays, when energized, switch the navigation unit VOR/LOC if input from the fin tip VOR/LOC antenna to the nose random localizer antenna. The forward antenna selected ground signals to flight computers A and B of the DFCS are also routed through energized contacts of the relays.