Position Reference
On position reference page 3, the flight crew can observe the calculated positions from the left and right GPS receivers and the left and right FMC calculations. This page also allows the flight crew to enable or disable GPS position updates.
This page can display the bearing/distance or latitude/longitude format. The bearing/distance format displays the positions relative to the active FMC position on the POS REF 2/4 page. In the example, both the left and right GPS agree with the left FMC position.
GPS L - Displays the left GPS position.
GPS R - Displays right GPS position.
FMC L (PRI) - Displays the left FMC calculated position.
Primary (PRI) is displayed in the line title of the FMC that is the navigation master.
Primary (PRI) is displayed in the line title of the FMC that is the navigation master.
FMC R - Displays the right FMC calculated position.
Primary (PRI) is displayed in the line title of the FMC that is the navigation master.
Primary (PRI) is displayed in the line title of the FMC that is the navigation master.
INDEX - Displays the INIT/REF INDEX page.
GPS NAV - Alternately selects GPS NAV ON (enabled) and OFF (disabled).
OFF - GPS position data is not available to the FMC. OFF displays in large letters; ON displays in small letters.
ON - GPS position data is available to the FMC. ON displays in large letters; OFF displays in small letters.
Note: When power is initially applied to the airplane or when engines are shut down, GPS NAV is set to ON.
BRG/DIST - Alternately changes the display of position data on POS REF 2/4, 3/4, and 4/4 to latitude/longitude format or bearing/distance format. The page illustration is shown in the bearing/distance display mode.