Troubleshooting NIC and NACp errors on ADS-B PAPR (Performance Report Request)

NIC (Navigation Integratory Category) encoding is used to indicate the radius of containment around the aircraft. 91.227 requires a minimum NIC or 7. NIC values of <7 will be flagged red within a PAPR when the MCF (Maximum Consecutive Failures) Threshold is exceeded. 

MCF (Maximum Consecutive Failures) is the number of non-performing reports received that occur in a row (consecutively). If an MDF exceeds its threshold, an MCF exception is identified for that parameter. 

NACp (Navigation Accuracy Category for position) filed indicates the accuracy of the aircraft position being transmitted. 91.227 requires a minimum NACp of 8. A PAPR will be flagged red if the NACp of <8 duration exceeds the allowable threshold. 

Follow the GPS troubleshooting Guide to help diagnose the issue with your installation. 

Most common errors:

1. Configuration of the tailBeacon. 

   Software update should be 1.5.1

   Offset is in Meters and not Feet. Make sure that the longitudinal and lateral offset of the tailBeacon is set to Meters and not Feet. 

2. Grounding of the tailBeacon
   1. Existing electrical system and wiring condition
   2. Panel switches
   3. Terminations
   4. Corroded connections
   5. Malfunctioning Alternators/generators/regulators
3.  Comm interference from 
   1. Aircraft Comm radios
   2. ELT - 121.5 and some 406