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Aviation Alerts and Advisories

Service Advisory 0835 Rev A: GPS Week Rollover in Flybuddy GPS and Model 2001/2101 GPS Systems


All Model 819 and Model 820 Flybuddy GPS units and all TSO-C115b Model 2001/2101 Systems with GPS sensors are affected.

Model 2001/2101 Systems with TSO-C129 GPS sensors are not affected.


Users of the Garmin AT legacy Model 819, Model 820 Flybuddy GPS, and TSO-C115b Model 2001/2101
Systems with GPS sensors have been experiencing degraded operation since Sunday, August 17, 2008.


The almanac data stored in the receiver has reached the end of the programmed GPS week. This has
resulted in an interruption of service or degradation of the operation of these legacy Garmin AT products.
The symptoms may include: no fix, a 2-D fix only, brief periods of a 3-D fix, and combinations of these
symptoms. In addition, the displayed almanac date will show as January x, 1989 or January x, 2089,
where x is the incremented date since the problem first occurred on August 17, 2008. Some units may
show the incorrect date but appear to operate normally otherwise.


At this time it has been concluded that these units cannot recover normal operation on their own. These
products utilize a GPS sensor purchased from a third party supplier. Garmin is in negotiation with this
vendor regarding a resolution to restore full functionality, and we hope to have a reasonably priced
solution for these units in place as soon as possible. More information on this issue will be posted to the
Garmin website in 10 to 15 business days.

Download 0835