Garmin GNC 420W Pilots Guide - Page 169

CDI Scales and Corresponding Flight Phases: Oceanic Enroute SECTION 9 AUX PAGES CDI Scale/Flight Phase: RAIM Protection: Auto (oceanic) 4.0 nm ±5.0 nm or Auto (enroute) 2.0 nm ±1.0 nm or Auto (terminal) 1.0 nm ±0.3 nm or Auto (approach) 0.3 nm Table 9-2 CDI Scales Terminal Approach Figure 9-54 CDI Scales During approach operations the CDI scale gradually ramps down even further, to 0.3 nm. This transition normally occurs within 2.0 nm of the final approach fix (FAF). If a lower CDI scale setting is selected (i.e., 1.0 nm or 0.3 nm) the higher scale settings are not selected during any phase of flight. For example, if 1.0 nm is selected, the GNC 420 uses this for the enroute and terminal phase and ramp down to 0.3 nm during an approach. Note that the Receiver Autonomous Integrity Monitoring (RAIM) protection limits listed in Table 9-2 follow the selected CDI scale and corresponding modes: An arrival alarm, provided on the CDI/Alarms Page, may be set to notify the pilot with a message when the aircraft has reached a user-defined distance to the final destination (the direct-to waypoint or the last waypoint in a flight plan). Once the aircraft has reached the set distance (up to 99.9 units), an 'Arrival at [waypoint]' message is displayed. • 'Units/Mag Var' - Allows the pilot to configure the displayed data to standard or metric units of measure. This setting applies to distance, speed, altitude, fuel, pressure, and temperature. Also provides three magnetic variation (heading) options: True, Auto, or User-defined. If 'Auto' is selected, all track, course and heading information is corrected to the magnetic variation computed by the GPS receiver. The 'True' setting references all information to true north, and the 'User' setting corrects information to an user-entered value. 190-00140-20 Rev. K GNC 420(A) Pilot's Guide and Reference 9-21