There is a specification for ADS-B Out when flying inside the rule airspace, but that does not apply outside of rule airspace or to ADS-B in, In the US regulations, it is specified as: (c) ADS-B Out Performance Requirements for NACP, NACV, NIC, SDA, and SIL— (1) For aircraft broadcasting ADS-B Out as required under Sec. 91.225 (a) and (b)— (i) The aircraft’s NACP must be less than 0.05...