extinguishes. Roll steering output returns to normal limit of
Data display, left and right: Composed of
lights which illuminate to display numbers, decimal points,
degree symbols, left and right directions, and latitude or
INSERT/ ADVANCE/ HI PREC key. Allows
insertion of loaded data into computer. Enters displayed data
into INS. When pressed before pressing any numerical key,
alternates display of normal and high precision data.
ALERT light. Illuminates amber to alert pilot
1.3 minutes before impending automatic course leg change.
Extinguishes when switched to new leg, if AUTO-MAN
switch is set to AUTO. Flashes on and off when passing
waypoint, if AUTO-MAN switch is set to MAN. Light will
extinguish if AUTO is selected or if a course change is
WARN light. Lights red to alert pilot 1 .;S
self-test circuits have detected a system fault. illumination
may be caused by continuous or intermittent condition.
Intermittent conditions light until reset by TEST switch. If
continuous condition does not degrade attitude operation,
light goes out when mode selector is set to ATT.
(7) Keyboard. Consists of 10 keys for entering
load data into data and TO-FROM displays. N, S, E. and W
(on keys 2, 8, 6, and 4) indicate direction of latitude and
longitude. TAC and DISP (on keys 7 and 9) enable loading
and display of TA(.'AN station data. MV/P and DISP (on
keys 3 and 9) are associated with loading and display of
magnetic variation, magnetic heading, and the pattern
steering mode. R/B and DISP (on keys 5 and 9) are
associated with loading and display of UTM coefficients and
waypoint move parameters.
CLEAR key. When pressed, illuminates and
erases data loaded into data displays or FROM-TO display.
Used to cancel erroneous data. After clearing, data loading
can be resumed.
WYPT CHG key. When pressed, enables
numbers in FROM-TO display to be changed. If
L.JSERT/ADVANCE key is pressed, computer will use
navigation leg defined by new number in all navigation
computations. If INSERT/ AD)VANCE key is not pressed,
computer will .continue using original numbers in all
navigation computations; but distance/time information,
based onnew leg, may be called up and read in data displays
(in case of waypoints). When not in TACAN mix mode,
TACAN station number is inserted to display DIS/TIME
AUTO-MAN TEST switch. This is a dual
purpose control. When the knob is pressed inward, the TEST
switch function is engaged. When the knob is rotated to
either the AUTO or MAN setting, the control serves as a
selector between those modes.
AUTO. Selects automatic leg switching
mode. Computer switches from one leg to the next-whenever
waypoint in TO side of the FROM-TO display is reached.
MAN. Selects manual leg switching
mode. Pilot must make waypoint changes manually.
TEST. When pressed, performs test of
INS lights and displays, remote lights and indicators
controlled by INS, and computer input/ output operations.
Used with other controls to activate display of numerical
codes denoting specific malfunctions and resets malfunction
During alignment, activates the HSI test. Continued
pressing of switch provides constant INS outputs to drive
cockpit displays in a predetermined fashion.
The INS can provide test signals to the
Horizontal Situation Indicator (HSI) and
connected displays. Pressing TEST switch
during STBY, ALIGN, or NAV modes will
cause all digits on connected digital displays
to indicate "8's" and illuminates the HSI
and ALERT lights. Additional HSI test
signals are provided when INS is in ALIGN
and the data selector is at any position
other than DSRTK/STS. Under those
conditions, pressing TEST switch causes the
HSI to indicate heading, drift angle, and
track angle error all at "0°" or "30°". At
the same time, cross track deviation is
indicated at "3.75" nautical miles (one dot)
right or left and INS-controlled HSI flags
are retracted from view.
Output test signal are also supplied to
the autopilot when INS steering is selected.
Rotating AUTO-MAN switch to
Change 5 3-48