4TAKEOFF TOURKey and Knob FunctionsBottom Row KeysNRST The nearest key (NRST) (GPS500W) displays the Nearest Airportspage. Then, turning the small rightknob steps through the NRST pages.CDI The CDI key (GNS 530W) is used totoggle the navigation source (GPS orVLOC) which provides output to anexternal HSI or CDI.OBS The OBS key is used to selectmanual or automatic sequencing ofwaypoints. Pressing this key selectsOBS mode, which retains the current“active to” waypoint as your naviga-tion reference even after passing thewaypoint (i.e., prevents sequencingto the next waypoint). Pressing theOBS key again returns to normaloperation, with automatic sequenc-ing of waypoints. Whenever OBSmode is selected, you may set thedesired course to/from a waypointusing the OBS Page, or an externalOBS selector on your HSI or CDI.MSG The message key (MSG) is used toview system messages and to alert youto important warnings and require-ments when the MSG annunciator isdisplayed. See Sections 12 and 9 formore information on messages andunit settings.FPL The flight plan key (FPL) allowsyou to create, edit, activate andinvert flight plans, as well as accessapproaches, departures and arrivals.A closest point to flight plan featureis also available from the flight plankey. See Section 4 for more informa-tion on flight plans.VNAV The vertical navigation key(VNAV) allows you to create a three-dimensional profile which guidesyou to a final (target) altitude at aspecified location. See Section 10.PROC The procedures key (PROC) allowsyou to select approaches, departuresand arrivals from your flight plan.When using a flight plan, availableprocedures for your departure and/orarrival airport are offered automati-cally. Otherwise, you may select thedesired airport, then the desiredprocedure.GPS 500W GNS 530W
