190-00728-04 Rev. A
Embraer Prodigy® Flight Deck 100 Pilot’s Guide
77
FLIGHT INSTRUMENTS
COURSE DEVIATION INDICATOR (CDI)
NOTE: During a heading change of greater than 105˚ with respect to the course, the CDI on the Arc HSI
switches to the opposite side of the deviation scale and displays reverse sensing.
The Course Deviation Indicator (CDI) moves left or right from the course pointer along a lateral deviation
scale to display aircraft position relative to the course. If the course deviation data is not valid, the CDI is not
displayed.
Figure 2-22 Course Deviation Indicator
CDI
Scale
Flight
Phase
Arc HSI
Navigation
Source
CDI
Crosstrack
Error
Flight
Phase
360º HSI
Navigation
Source
Scale
CDI
TheCDIcandisplay twosourcesofnavigation: GPSorNAV(VOR/LOC). Thecolorindicatesthe current
navigation source: magenta for GPS or green for VOR and LOC. The full scale limits for the CDI are defined by
a GPS-derived distance when navigating GPS. When navigating using a VOR or localizer (LOC), the CDI has
the same angular limits as a mechanical CDI. If the CDI exceeds the maximum deviation on the scale (two dots)
whilenavigatingwithGPS,thecrosstrackerror(XTK)isdisplayedbelowthewhiteaircraftsymbol.
Figure 2-23 Navigation Sources
Yellow
Indicates
Navigation
Source
Selected on
Both PFDs not
Synchronized