2 - NAV PAGES59Dead ReckoningDead reckoning is the process of continuing navi-gation using your last known position and speed aftera loss of GPS navigation while on an active flight plan.CAUTION: Navigation using dead reckoning istherefore only an estimate and should not beused as the sole means of navigation. Use othermeans of navigation, if possible.Dead reckoning becomes active after a loss of GPSposition while you are navigating using an active flightplan. A pop-up message will appear and you mustclear the message before continuing operation.The ownship icon color is changed to yellow. The To/From flag is removed from the CDI. The Dead Reckon-ing annunciator (DR) appears on the left side of themap display when GPS position is unavailable and theunit is in Dead Reckoning mode. All external outputsdependent on GPS position are flagged.Terrain will be noted as not available and new terrainadvisory pop-ops will not occur. Traffic and Storm-scope information will not be shown on the Map page,but will continue to be available on their own dedi-cated pages. XM weather will still be available on theMap page.Dead Reckoning mode will continue until GPS posi-tion is restored, when GPS navigation is restored DeadReckoning mode is exited. The DR annunciationswill be removed and GPS information will be used tocompute navigation related information for the currentflight phase.Dead Reckoning is only allowed in En Route andOceanic flight modes. If the unit is in a Terminal orApproach flight mode when Dead Reckoning takesplace, “No GPS Position” will be displayed on the mappages and all navigation data will be dashed. If you areoperating in Dead Reckoning mode and a transition toTerminal or Approach flight modes would occur fromthe projected Dead Reckoning position, Dead Reckon-ing mode will be discontinued. “No GPS Position” willbe displayed on the map pages and all navigation datawill be dashed.Dead Reckoning
