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Position Selector Mode System Left Display Right Display
TK/STS DSR NAV ALIGN STBY blank in ALIGN mode. increments. Left display is 359.9 degrees in 0.1-degree point display, from 0 to navigation between the way-true north for great circle in NAV mode with respect to Displays desired track angle ment status from 90 to 10 In ALIGN mode, displays align-and nav status. malfunction maintenance code button is pressed, will read code or when the HOLD push-Will read recommended action action and malfunction codes. Reads alignment status,
display is 01 in NAV mode. in 1-unit increments. Right increments, decreasing to 02 (except 30 and 20) in 10-unit
NAV ALIGN 0 to 359.9 degrees in 0.1-degree increments. Displays preselected track when FROM/TO display reads 99 from
TEST NAV ALIGN STBY annunciators and TK CHG, INSERT and HOLD indicators are on. is R. From/To display is all eights, ALERT, BATT and WARN NS, EW, and all eights, except left digit of right display tors. Left and right numerical displays show 3 dots each, Provides a quick check of CDU display elements and annuncia-
Control/Display Outputs
Figure 9 (Sheet 3)
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(f)
solves mechanization equations associated with calibration and updating performance parameters of the INS components
(g)
tests for and isolates INS malfunctions
3. Mode Selector Unit (Fig. 7)__________________
A. The mode selector unit (MSU) is used to energize and align the system prior to flight and then select the navigate and attitude reference modes of operation. There are three MSU units installed at the pilots' overhead panel (Fig. 1) to control the operation of INS No. 1, 2 and 3 systems. Each unit contains a mode selector switch, two annunciators, READY NAV and BATT, and a remote access switch labeled OFF, TEST and BIAS (for program control) located behind a removable access cover. The mode selector is heavily detented in the NAV position to prevent inadvertent shutdown in flight. The MSU controls and annunciators are described in Fig. 8.
B. The primary operating modes, selected by the mode selector switch, and MSU indications are as follows:
(1)
OFF - Power is applied to the MSU and CDU edge lighting and CDU data keyboard. System primary power is off.
(2)
STBY - Control display unit is fully operable to allow display test and insertion of airplane present position. The gimbal assembly cages to the airplane axes, and platform temperature stabilization and gyro runup are initiated. The system is not affected by airplane movement. During initial turn-on, the right numerical display provides a readout of the computer program number.
(3)
ALIGN - System automatically levels itself and determines the wander angle. When alignment is complete, the READY NAV light comes on indicating the NAV mode may be entered. The airplane must not be moved during alignment; however, fuel, cargo and passengers may be loaded. The status of alignment sequence can be checked by placing the display selector to DTK/STS and observe countdown from 90 to 02 on right numerical display.
NOTE: If the mode switch is moved from ALIGN to STBY position, it
____ must be recycled back through the OFF position and the system realigned. The alignment cannot be maintained while the airplane is moved by just changing mode switch from ALIGN to STBY, moving the airplane and then returning mode switch to ALIGN position. The system must be allowed to enter NAV mode or turned off and returned to STBY mode before the airplane can be moved.
(a) During the attitude slew test procedure, the mode selector is set to the ALIGN position.
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(4) NAV - This is the normal inflight operating mode of the system and must be selected prior to moving the airplane. The computer receives acceleration information from the platform and computes airplane position and guidance information. If CDU data selector is set to DSR TK/STS while INS is in NAV mode, right numerical display will indicate status 01.
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