(2) INSERT/ADVANCE key - Depress.
(3) Left-hand and right-hand displays - Read arcseconds related to present inertial position to
nearest a tenth of a second.
(4) HOLD key - Depress to return to INS normal operation.
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
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
Distance and Time to Next Waypoint - Check as follows: