TM 55-1510-221-MTF
PROCEDURE
TROUBLESHOOTING
REFERENCE
degree. Compare with values noted
in latitude and longitude position
check above.
(3)
INSERT/ADVANCE key - Depress.
(4)
Left-hand and right-hand displays -
Read arc-seconds related to present
inertial position to the nearest a
tenth of a second.
(5)
HOLD key - Depress to return to INS
normal operation.
h.
Magnetic variation - Check as follows:
(1)
Keys 3 and 9 - Depress
simultaneously.
(2)
Right-hand display - Read magnetic
variation to a tenth of an arc-minute.
Compare with local values.
NOTE
While operating in the NAV mode, magnetic
variation is computed when aircraft roll is
less than 9
and the magnetic heading input
is valid (absence of error code 17)
(3)
DATA/SELCTOR - Momentarily set
to any position except L/L WYPT to
return to normal INS display mode.
4-15
