The FMS prompts the pilot at 6L and 6R for the most likely functions to be selected. Using these prompts, the FMS steps the pilot through procedures such as initialization. At any time, it is possible to operate out of sequence or to access other areas of the FMS. Follow Procedure 3--2 to access any function of the FMS.
Step Procedure 3--2 Accessing Any FMS Function
1 Determine the required function. All functions are available at all times from the PERF, NAV, FPL, PROG or RTE keys.
2 Select the correct PERF, NAV, FPL, PROG or RTE key.
3 When PERF or NAV is selected, read the menu list for the required function or feature.
4 Select the correct function or feature.
5 The FMS displays the function or feature selected.
6 Continue working using the prompts at 6L and 6R when part of a sequence, such as initialization, is being completed.
Annunciators
Annunciators are displayed on the electronic display system (EDS).
Magenta indicates an advisory annunciator and amber indicates an alerting annunciator.
D Dead Reckoning (DR) -- DR is an alerting (amber) annunciator.
This annunciator is displayed or lit when operating in the DR mode.
The FMS enters DR mode after loss of required navigation performance (see DGRAD) and loss of radio updating and all other position sensors (IRS and GPS) for greater than 2 minutes.
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D Degraded (DGRAD) -- DGRAD is an alerting (amber) annunciator.
This annunciator is displayed when the FMS loses required navigation performance (RNP). This is accompanied by the UNABLE RNP scratchpad message.
The DGRAD annunciator is displayed on the horizontal situation indicator (HSI) and LNAV display when FMS is the selected aircraft navigation source on EDS and any of the following conditions exist:
— FMS estimated position uncertainty (EPU) is greater than RNP
— FMS position integrity estimate is greater than the integrity alarm limit (this occurs when EPU is slightly less than RNP)
— GPS is not available and GPS is required for the selected flight plan procedure.
When the DR annunciator is displayed or lit when the DGRAD annunciator is displayed or lit, the DGRAD annunciator is removed or turned off.
D Message (MSG) -- The MSG annunciator is shown on the MCDU when there is a message on the MCDU scratchpad. The annunciator is removed or turned off after the message(s) has been cleared from the scratchpad.
Messages are displayed in the MCDU scratchpad at various times.
Messages inform or alert the pilot as to system status. Messages are divided into the following two major groups:
— ADVISORY MESSAGES -- Advisory messages contain information helpful to the pilot. Advisory messages are normally the result of a pilot action on the MCDU (e.g., making an entry with the incorrect format). These messages do not turn on the MSG annunciator.
— ALERTING MESSAGES -- Alerting messages alert the pilot to the FMS status, assuming the pilot is not looking at the MCDU (e.g., a message annunciating a sensor failure).
Messages are stacked for display in priority order on a first in, last out basis. In cases where there are multiple messages stacked, the message annunciator remains displayed or lit until all messages are cleared. Only one message is cleared per CLR key push.
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D Approach (APPR) -- APPR is an advisory (magenta) annunciator.
The annunciator indicates the FMS is in the approach mode of operation. In this mode, the EDS deviation sensitivity and FMS tracking gains are increased. The approach annunciator is displayed when ALL of the following conditions are valid:
— The FMS is the selected aircraft navigation source on EDS.
— A nonprecision instrument approach must have been activated from the navigation database. When no approach, or an instrument landing system (ILS), localizer (LOC), localizer--back course (LOC--BC), landing directional aid (LDA), or simplified directional facility (SDF) is selected, the APPR annunciator does not light.
— The aircraft position is between 2 NM outside the final approach fix (FAF) and the missed approach point (MAP).
— The DGRAD annunciator must not be displayed.
— When the approach requires the use of GPS, GPS navigation mode must be valid.
D Terminal (TERM) -- TERM is an advisory (magenta) annunciator.
TERM indicates the FMS is in the terminal area and required navigation accuracy has increased. Neither DGRAD nor DR are displayed for this annunciator to be displayed.
D Lateral Track Alert (WPT) -- WPT is an advisory (magenta) annunciator. The FMS gives a lateral track annunciator (WPT) 30 seconds prior to sequencing a waypoint.
D Vertical Track Alert (VTA) -- VTA is an advisory (magenta) annunciator. A vertical track annunciator is given to warn of impending FMS vertical track command changes.
A VTA is issued for the following conditions:
— The aircraft is within 1,000 feet of capturing an altitude constraint that is not collocated with the altitude preselect
— In CRUISE, one minute prior to top--of--descent (TOD)
— One minute prior to resuming a climb or descent from a constrained waypoint
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— Prior to resuming a vertical flight level change (VFLC) descent due to a speed limit altitude level--off
— In CRUISE, 1 minute prior to executing a step climb.
The VTA is also issued as an audible annunciator.
D Lateral Offset (OFFSET) -- OFFSET is an advisory (magenta) annunciator. The FMS gives the capability to define and fly a parallel offset of up to 30 NM on any track to a fix (TF) or course to a fix (CF) leg that is not included in an approach or hold. A parallel offset can also be flown to a direct to a fix (DF) leg following the final turn.
D Required Navigation Performance (RNP) -- RNP is an advisory (magenta) annunciator. It is the RNP value for the current phase of flight.
D Localizer Performance With Vertical Guidance (LPV) -- The GPS reference path identifier is an advisory (magenta) annunciator.