Navigation/Displays Source Select Panel

 

The VHF NAV switch on the navigation/displays source select panel is a three position switch. The positions are; BOTH ON 1, NORMAL, and BOTH ON 2. This switch changes the source of the data that the DEUs use for the ILS displays.

In the NORMAL position, MMR 1 supplies data for the captain displays and MMR 2 supplies data for the first officer displays. When you select BOTH ON 1, the DEUs use MMR 1 as the source for the captains displays and first officers displays.

When you select BOTH ON 2, MMR 2 is the source for the captains displays and first officers displays.

Discrete signals also go to the flight control computers (FCCs) to signal that the switch is not in the normal position.