ALIGN

• Rotating the selector from OFF to ALIGN initiates the alignment cycle
• Rotating the selector from NAV to ALIGN automatically updates alignment and zeroes ground speed error.

NAV (detented position) 

• System enters the NAV mode after completion of the alignment cycle and entry of present position
• In NAV mode, all IRS information is available to airplane systems for normal operations.

ATT

• Provides only attitude and heading information:
• Attitude information is invalid (attitude flag in view) until ALIGN Light is extinguished
• Heading information is invalid (heading flags in view) until the actual magnetic heading is manually entered and the

ALIGN Light is extinguished

• Position and ground speed information is not available until the IRS is aligned on the ground
• The selector must be cycled to OFF before reselecting ALIGN or NAV.