3-3-50. Preflight Procedures.

3-3-49. General Operating Procedures for Entering Data. The panel display consists of four line LCD readout. The top line of the display is reserved for the display of Fly-To- destination number and destination name/International Civil Aeronautic Organization (ICAO) identifier, EPE in meters, mode of GPS and mode of AN/ASN-128B opera- tion and target store number. The remaining lines will display data in accordance with the DISPLAY and MODE switches. When depressing the KYBD key for the first time in an entry procedure, the display freezes, kybd is displayed in the bottom right corner indicating the display is in the keyboard mode and the input field under key- board control blinks. If it is not desired to change the display field under control, the pilot can advance to the next field of the display by depressing the KYBD key again. Depressing ENT key (whether or not new data has been entered) causes the display to blank momentarily and return with the latest computed data. To abort a keyboard operation, move the mode or display switch to another position. NOTE All keys activate upon release after being de- pressed. Keys should be depressed and im- mediately released in one continuous motion. a. Data Entry. To display a letter, first depress the LTR key corresponding to the position of the desired letter on a key. Then depress the key which contains the desired letter. For example, to enter an L, first depress The LTR RIGHT key, then depress the 4 key. b. Keyboard Correction Capability. The last charac- ter entered may be cleared by depressing the CLR key. If the CLR key is depressed twice in succession, the field is cleared but remains under control (indicated by blink- ing) and the last valid data entered is displayed. c. Destination Variation Constraint. The magnetic variation associated with a destination must be entered AFTER the coordinates for that destination are entered. The order of entry for present position is irrelevant. d. Impossibility of Entering Unacceptable Data. In most cases the computer program will reject unaccept- able data (for example, a MGRS area W1 does not exists and will be rejected). If the operator attempts to insert unacceptable data, the unacceptable data will be dis- played on the panel and then the selected field will blink after ENT key is pressed displaying the last valid data. NOTE The computer cannot prevent insertion of er- roneous data resulting, for example, from hu- man or map errors. e. Procedure for Displaying Wind Speed and Direc- tion. NOTE In MGRS mode, wind speed is displayed in km/hr; in LAT/LONG mode, wind speed is dis- played in knots. Wind direction is defined as the direction from which the wind originates. (1) Set MODE switch to LAT/LONG (MGRS may also be used). (2) Set DISPLAY switch to WINDUTC/DATA and observe display. (3) The display indicates: SP;XXXKn DIR:XXX_ f. Procedure for Displaying/Entering UTC and Dis- playing GPS Status. (1) Set MODE switch to LAT/LONG (MGRS may also be used). (2) Set DISPLAY switch to WIND-UTC/DATA and observe the wind speed/direction display. (3) Depress ENT key. Observe that the CDU display indicates year XX, day XXX and indicates hours, minutes, and seconds of UTC time: XX Hours, XX Min- utes, XX Seconds. (4) To enter year, day, and time depress the KYBD key to select the field for input shown as a blinking field, enter the desired data and depress the ENT key. (5) To display GPS status depress the ENT to display selection menu. 1>SEA CURRENT 2>SURFACE WIND 3>GPS STATUS 4>DATA LOAD end (6) To select the GPS STATUS page depress the 3 key.

d. Self-Test

TM-1-1520-240-10 Army CH-47D Heilcopter (EIC:RCD) Manual
Page Navigation
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TM 1-1520-240-10 3-3-22 (7) Observe the CDU display. The display indi- cated the GPS test mode status as of one of the follow- ing. GPS TEST: IN PROCESS GPS TEST: NOT RUN GPS TEST: PASSED GPS TEST: FAILED g. Procedure for Displaying GPS Key and GPS Space Vehicle Status. (1) Set the DISPLAY switch to XTK/TKE/KEY. (2) Set the MODE switch to LAT/LONG (MGRS may also be used). (3) The display indicates GPS daily key status, time remaining on the currently entered keys and how many Space Vehicles (SV) are currently being used by the GPS. KEY STATUS TIME REMARKS DK OK Days or hours still available on key GPS daily key in use and verified. DK NO * No GPS daily key available DK IN * GPS daily key available but not verified. 3-3-50. Preflight Procedures. a. Data Required Prior to DGNS Turn-on The following initial data must be entered by the pilot after system turn-on and initialization, unless previously en- tered data is satisfactory: Datums of operation, when using MGRS coordinates. This data may be part of the data load if preprogrammed. In combined or GPS mode the GPS provides preset posi- tion. If Doppler only mode is selected MGRS coordinates of present position - zone area, easting and northing; latitude/longitude coordinates may also be used to input present position. This data may be part of the data load if preprogrammed. Variation of present position to the nearest one-tenth of a degree. Coordinates of desired destinations 00 through 99. It is not necessary to enter all destinations in the same coor- dinate system. This data may be part of the data load if preprogrammed. Variation of destinations to the nearest one-tenth of a degree. Crypto-Key variables necessary to enable the GPS re- ceiver to operate in Y code are entered via remote fill data only and not via the CDU keyboard. NOTE Destinations are entered manually when steering information is required to a destina- tion that was not in the set of data loaded via the data loader, or it is desired to update pres- ent position by overflying a destination, or a present position variation computation is de- sired. (See CDU operation). If a present posi- tion variation update is desired, destination variation must be entered. The operator may enter one or more destination variations; it is not necessary for all destinations to have as- sociated variations entered and also not nec- essary to enter all destinations in any case, but variations must be entered AFTER des- tination coordinates are entered. The Doppler outputs true heading and accepts magnetic heading from gyromagnetic heading reference. If accu- rate magnetic variations are not applied, then navigation accuracy will be affected. b. System Initialization (1) Enter GPS mode “M”. NOTE You must select GPS mode “M” during initial- ization. If “Y” mode is selected before Crypto- Key variables are loaded the system will lock- up forever. You must select GPS mode “M” during initial- ization. If “Y” mode is selected before Crypto- Key variables are loaded the system will lock- up forever. (2) Perform self test (para d. below). (3) Perform download (para c. below) of data loader cartridge if necessary, or manually enter datum, destinations, magnetic variations, and present position (para. f or g. below). (4) Load Crypto-Key variables (unless pre- viously loaded and still valid) necessary for operation of the GPS in Y mode. NOTE It is necessary to wait at least 12 minutes for key validation when new keys have been en- tered, or collection of almanac data when set has no previous almanac data. During this time the GPS operating mode must be M and uninterrupted. After this time the GPS operat- ing mode may be switched to Y. Observe the GPS Key status and number of SVs tracked after switching to Y mode. If the SV number goes to zero repeat this procedure. The Key status shall switch from DK IN to DK OK sometime during the 12 minutes. (5) Check datum of operation, if MGRS is being used.

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