navigation systems

On which FMS-CDU pages are route modifications entered?

LEGS or RTE page as a waypoint. — Route changes are made by editing route legs or route-page waypoint entries; the FMC treats those entries as modifications until they are executed. [Ref: FCOM 11.42.16]

Can the flight crew change the GMT on the POS INIT page?

No — GMT is a system time reference rather than a pilot-editable route or performance entry, so the POS INIT page does not provide a crew-entry field for changing it. [Ref: FCOM 11.47.1]

Waypoint speed and altitude constraints are entered on which FMS-CDU page?

LEGS page — Waypoint crossing restrictions belong to the route leg itself. The LEGS page is therefore where speed and altitude constraints are entered and associated with a specific waypoint. [Ref: FCOM 11.31.25]

What FMS-CDU page displays the FMC and IRS positions and ground speeds?

POSITION REFERENCE 2/3 — The POSITION REFERENCE pages are used to compare the FMC computed position with the individual IRS position solutions and their associated ground-speed data. [Ref: FCOM 11.40.12]

How can an active route be cleared?

Enter a new destination — Entering a new destination replaces the destination of the active flight plan and clears the route beyond the new endpoint, which is why it can be used to clear the active route. [Ref: FCOM 11.49.1]

What does the FMS-CDU DSPY light mean?

Current display is not related to the active leg or current performance mode. — The DSPY light is a cue that the CDU page currently being viewed is not the page normally associated with the active flight phase or active route leg. [Ref: FCOM 11.10.4]

Which cost index provides maximum range?

Zero — A cost index of zero minimizes the time-related cost component and drives the FMC toward minimum-fuel / maximum-range style speeds rather than faster time-saving speeds. [Ref: FCOM 11.31.3]

The supplementary normal procedure for IRS fast alignment requires entering present position. True or False?

True — Fast realignment is not only a selector movement: the IRUs need a current position reference before being returned to NAV, allowing the shortened realignment to update position quickly. [Ref: FCOM 11.20.3]

What informs the flight crew that the active navigation leg cannot be intercepted by following the present heading?

FMC message - NOT ON INTERCEPT HEADING — The message is generated when the FMC geometry shows that maintaining the present heading will not intercept the active leg, prompting the crew to revise the intercept. [Ref: FCOM 11.60.7]

What does the FMC database contain?

Navigation, operational program configuration (OPC), aero engine database (AEDB), MAGVAR tables — The FMC uses several stored data sets: navigation data for routing, software/configuration data for FMC operation, engine/aerodynamic performance data, and magnetic-variation data for true/magnetic conversion. [Ref: FCOM 11.32.1]

When route 1 is active, how can route 2 be activated?

Activating and executing RTE 2 or LEGS 2 — Route 2 is maintained as a separate inactive route. It becomes the active flight plan only after the crew selects that route/legs set, activates it, and executes the change. [Ref: FCOM 11.48.1]

When does the FMS clear the latitude and longitude entry from the SET IRS POS line on the FMS-CDU POS INIT page?

When all IRUs enter the navigation mode. — The entered position is needed while the IRUs are aligning. Once all IRUs have reached NAV mode, that temporary initialization entry is no longer required and is cleared. [Ref: FCOM 11.20.3]

What information may be entered into the FMS-CDU WAYPOINT WINDS page?

Forecast wind and temperature up to 4 altitudes — Waypoint winds allow the FMC to build a vertical wind/temperature profile at the waypoint; multiple altitude entries improve cruise and descent predictions through changing wind layers. [Ref: FCOM 11.31.23 and FCOM 11.42.1]

Which is true regarding the ILS radios?

Tuned automatically or manually — ILS frequency selection can be supplied automatically by the FMC when appropriate, while manual tuning remains available to the crew when a specific station or frequency must be selected. [Ref: FCOM Chapter 11 — Flight Management, Navigation]