Garmin GPS 500 Pilot's Manual & Reference page 233

OBS key stuck - The OBS Key is stuck in the
enabled (or pressed) state. Try pressing the OBS
Key again to cycle its operation. If the message
persists, contact a Garmin dealer for assistance.
Poor GPS coverage - The GPS receiver cannot
acquire a sufficient number of satellites to
compute a position and provide navigation.
Power down and re-initialize - The GPS 500
cannot calculate a position due to abnormal
satellite conditions. The unit is unusable
until power has been cycled off and back on.
Abnormal satellite conditions may exist and
the pilot may need to use an alternate means of
navigation.
RAIM is not available - Receiver Autonomous
Integrity Monitoring (RAIM) has determined that
sufficient GPS satellite coverage does not exist for
the current phase of flight. (The CDI/HSI NAV
flag also appears.) Select an alternate source for
navigation guidance.
RAIM not available from FAF to MAP
waypoints - When performing an instrument
approach, Receiver Autonomous Integrity
Monitoring (RAIM) has determined that sufficient
GPS satellite coverage does not exist to meet the
required protection limits. Select an alternate
source for navigation guidance.
190-00181-60 Rev. G
RAIM position warning - Although sufficient
GPS satellite coverage may exist, Receiver
Autonomous Integrity Monitoring (RAIM) has
determined the information from one or more
GPS satellites may be in error. The resulting
GPS position may be in error beyond the limits
allowed for the current phase of flight. Cross-
check the position with an alternate navigation
source. If the warning occurs during a final
approach segment (FAF to MAP), execute the
published missed approach.
Scheduler message - [user entered text] - The
user-entered scheduler message time has expired,
and the scheduler message is displayed.
Searching the sky - The GPS 500 is searching
the sky for GPS satellite almanac data or the GPS
receiver is in AutoLocate Mode. Allow the unit
to complete data collection (approximately five
minutes) before turning it off.
Select auto sequence mode - The OBS Key was
pressed, disabling auto sequencing of waypoints
(in a flight plan or instrument procedure). The
OBS Key should be pressed again to enable auto
sequencing, because 1) no destination waypoint
has been selected or 2) the GPS receiver cannot
currently determine its position.
GPS 500 Pilot's Guide and Reference
SECTION 14 – MESSAGES,
ABBREVIATIONS, & NAV TERMS
14-5