(d)
The entire 24 character spaces of the fourteenth line of the display are used as a scratch pad block for entry of data from the keyboard, or for display of failure messages, operational alerts, and advisory prompts. When a message appears, it is to alert the operator to the occurrence of system or external sensor failures, performance limitations, and errors in manual data entry routines. All messages which appear in the scratch pad can be cleared by using the CLR key of the CDU. Messages will normally be accompanied by illumination of the MSG annunciator at the right side of the CDU panel. The annunciator will be extinguished when the message is cleared from the scratch pad.
(2) The remainder of the display (twelve 24-character lines) is available for use in displaying data without restriction. This data can consist of information directly applicable to operation of the airplane. The data can also consist of a menu, which allows selection of system functional options.
C. Alphanumeric Key Group
(1) The CDU alphanumeric keyboard provides the operator with a means of entering data into the system for initialization of the LNAV/VNAV navigation and guidance modes, and for modification of flight plans. The alphanumeric key group also includes the special-purpose slash (/), change sign (+/-), decimal point (.), and clear (CLR) keys. All entries initiated by operation of the alphanumeric keyboard initially appear in the scratch pad area of the display. The scratch pad contents can be edited or cleared by pressing the CLR key. When an entry is present in the scratch pad, a brief depression of the CLR key will clear the last character in the entry. If the CLR key is held down for more than 1 second, the entire entry in the scratch pad will be cleared. The slash key serves to separate data fields where multivariable entries are employed. An example of this type of entry is the definition of a climb speed schedule target airspeed and mach number (300/.780). The decimal point key inserts a decimal point into the scratch pad character string when pressed. The change sign key alternately changes the entry in the scratch pad from a positive to a negative quantity and back again. Repeated depressions of the change sign key simply toggle the positive or negative sense of the scratch pad entry.
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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737-300/400/500MAINTENANCE MANUAL
D. Flight Phase and Function Key Group
(1)
This group of 13 keys represents the capabilities of the FMCS most used during operation of the airplane. These keys provide the means for operator access to the flight planning functions of the FMCS. The specifics of flight phases (CLB, CRZ, and DES) can also be selected, once initially addressed, for display by using keys of this group.
(2)
Flight Phase Keys
(a) The phases of flight that can be preplanned and controlled by the FMCS are climb, cruise, and descent. Within each flight phase specific flight modes of operation can be selected. The keys used to access the flight mode displays, for the climb, cruise and descent phases are: 1) CLB (climb) key, displays current or alternate climb mode
for assessment and selection. Top-of-Climb (T/C) altitude
is enterable, as are speed/altitude restrictions.
2) CRZ (cruise) key, displays current or alternate cruise mode for assessment and selection. Information about optimum altitude, step-climb savings, and turbulence penetration N1 targets is also available.
3) DES (descent) key, displays current or alternate descent mode for assessment and selection. End-of-Descent (E/D) altitude is enterable, as are the airport-related speed/altitude restrictions. Flight Path Angle (FPA), Vertical Speed (V/S), and Vertical Bearing (V/B) information is provided for pilot reference.
(3) Function Keys
(a) The capability of the FMCS to manage a flight is based, in part, on operator utilization of the functions associated with the following keys: 1) INIT/REF (initialization/reference) key, allows access to
data pages required for the start-up of the FMCS and IRS. Also, the operator may select various reference data and maintenance pages.
2) N1 LIMIT key, permits manual command of the active N1 limit, and selection of any N1 Limit Derate that may apply.
3) DEP/ARR (departures/arrivals) key, is used for selection of the procedures and runways at the operator entered origin and destination airports.
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本文链接地址：737-300 400 500 AMM 飞机维护手册 导航 NAVIGATION 5(32)
