The GPS accuracy displayed in ForeFlight Mobile when connected to a Lynx is based on the Navigation Accuracy Category for Position (NACp) standard. This value represents the accuracy of the aircraft's horizontal GPS position with a 95% probability.
The NACp value determines the precision of the position information and is critical for compliance with 14 CFR 91.225 for ADS-B airspace. A minimum NACp value of 8 is required to operate in ADS-B airspace. The table below outlines acceptable NACp values 8-11 and the GPS accuracy shown in ForeFlight Mobile:
| NACp Value | GPS Accuracy Limits | GPS Accuracy Value Shown in ForeFlight Mobile |
| 8 | Value is between 92.6m and 30m | 92.6m |
| 9 | Value is between 10m and 30m | 30m |
| 10 | Value is between 3m and 10m | 10m |
| 11 | Value is less than 3 meters | 3m |
Seeing accuracy values of 92.6m, 30m, 10m, or 3m in ForeFlight is normal and reflects the NACp standard. Variations in GPS accuracy are expected during operations and do not indicate a problem with the system.
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