Garmin GPS 500 Pilot's Manual & Reference page 231

Display backlight failure - The 500 Series unit
has detected a failure in the display backlighting.
The unit should be taken to your Garmin dealer
for service.
Do not use for navigation - The 500 Series unit
is in Demo Mode and must not be used for actual
navigation.
FPL has been truncated - The flight plan (FPL)
was truncated because not enough room existed
to insert an approach, departure, or arrival. This
message also appears when an approach has
been deleted from a stored flight plan because an
approach could not be found. These conditions
may occur upon power up when a database
change increases the number of waypoints in,
or removes an approach from, an instrument
procedure.
FPL is full - remove unnecessary waypoints
- An attempt has been made to add more than 31
waypoints to a flight plan (FPL). The 500 Series
unit does not allow more than 31 waypoints per
flight plan.
FPL leg will not be smoothed - The upcoming
flight plan (FPL) leg is too short for smooth
waypoint transitions. Expect a rapid change in
the CDI.
FPL waypoint is locked - At least one flight plan
(FPL) waypoint is locked because the waypoint
has been removed from the current NavData card
(database change), the data card is missing, or the
data card has failed.
FPL waypoint moved - The position data for
one or more flight plan (FPL) waypoints moved at
least 0.33 arc minutes in the current NavData card
(database change).
190-00181-60 Rev. G
FPL waypoint was deleted - At least one flight
plan (FPL) waypoint is no longer available when
a new NavData card was installed (database
change).
GPS is not responding - Internal system-
to-system communication between the main
processor and the GPS receiver has failed.
Operational status of the GPS receiver is unknown
and the unit should be returned to a Garmin
dealer for service.
GPS needs service - The GPS 500 has detected a
failure in its GPS receiver. The GPS receiver may
still be usable, but the unit should be returned (at
the earliest convenience) to a Garmin dealer for
service.
GPS stored data was lost - Satellite almanac,
ephemeris and time data have been lost due to
a memory battery failure, system reset, or data
expiration (data over six months old).
Heading input failure - The heading selection
on the external HSI' s (or CDI' s ) OBS course
selector cannot be read properly. A Garmin dealer
may need to check the installation.
Inside airspace - A GPS-calculated position lies
within the boundaries of a special use airspace.
This message is automatically disabled within
30 nm of an arrival airport, when an approach is
loaded.
Invalid closest pt of FPL - A closest point
cannot be created from the waypoint entered on
the 'Closest point of flight plan' window. This
occurs when the selected waypoint is beyond the
limits of all legs in the flight plan, too far away,
or when a unique waypoint name for the closest
point cannot be created.
GPS 500 Pilot's Guide and Reference
SECTION 14 – MESSAGES,
ABBREVIATIONS, & NAV TERMS
14-3