[3] The flight phase and function key group has 13 keys. This group represents the capabilities of the FMCS most used during operation of the airplane. The phases of flight that can be preplanned and controlled by the FMCS are climb ( CLB), cruise ( CRZ) and descent ( DES). The capability of the FMCS to manage flight is based on the utilization of the fallowing function keys:
INIT/ REF (initialization lreference) key, DIR/INTC (direct/ intercept ) key, N1 LIMIT key, RTE ( route) key, LEGS ( route lege) key, FIX ( fix information ) key, DEP/ARR (depature /arrivals ) key, HOLD key, PROG (flight progress) key, and EXEC (execute ) key.
Entry of the data into the operational display is accomplished by pressing an appropriate line select key ( LSK). Twelve LSKs are provided on the CDU panel, six on each side of the CRT. The placement of the LSKs aligns them with the third , fifth, seventh , ninth, eleventh , and thirteenth lines of the display. Data entries are permitted in those lines only. Some displays provide menus of function or mode options that can be selected by the operator, and in these cases the LSKs are used to accomplish that selection. In addition to transferring data from the scratch pad up to the data display, the LSKs can be used to duplicate data from the display lines into the scratch pad. When the scratch pad is empty, pressing the LSK associated with the data required copies the data into the scratch pad. The delete ( DEL) key is a special purpose key which is used to remove data from the display after the data has been line selected and accepted into a data field. The DEL key must be pressed once for each parameter to be deleted.

[4] If a function has more than one page of display data associated with it, the page number block at the upper right corner of the CRT display will indicate this . The page number consists of two numbers separated by a slash. The first number indicates what page is currently displayed, and the second number indicates the total number of pages in the string. Pressing the NEXT PAGE key advances the display to the next higher numbered page, while pressing the PREV ( previous ) PAGE back up the display to the next lower numbered page. The page strings are continuous.

[5] There are 4 annunciator on the front of the CDU, only two are used by the 737 FMCS. The 2 annunciators are MSG and FAIL. The MSG annunciator is white in color, and is illuminated to indicate to the operator the presence of an alert or advisory message. The FAIL annunciator is amber in color and is illuminated if any system failure is detected by the BITE of the FMC.

[6] The FMCS has a set of messages which are displayed in the scratch pad of the CDU when conditions warrant their appearance. The three categories of messages, listed in order of highest priority, are:
 Alerting messages
 Entry error advisory messages
 Advisory messages
Alerting messages indicate to the crew some condition which must be acknowledged and remedied by them before further FMCS-guided flight is advisable or possible. These messages appear on both CDUs. The entry error advisory messages indicate to the crew that an entry of data from the scratch pad into a data field is not correct. The crew must clear the message and repeat the entry in the proper manner. These messages appear only on the CDU on which the data entry attempt was made. The advisory message indicate system status regarding readiness for operation or prediction of profile parameters. These messages appear on both CDUs. Existence of a message in the scratch pad on any page, even if the page on which the message appears is not currently displayed on the CRT, will illuminate the CDU's MSG light.
　
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本文鏈接地址：第31課 大氣數據系統 LESSON 31 AIR DATA SYSTEM(33)