RNAV and RNP Navigation Specifications
Navigation specifications define the performance requirements (accuracy, integrity, etc.) that the aircraft and crew must meet to operate in a defined airspace.
Specification Types
There are two main types, differentiated by the requirement for on-board monitoring and alerting:
- RNAV (Area Navigation):
- Does NOT require on-board performance monitoring and alerting.
- Examples: RNAV 10, RNAV 5, RNAV 1.
- RNP (Required Navigation Performance):
- DOES require on-board performance monitoring and alerting.
- The system alerts the pilot if the required accuracy is not met (ANP > RNP).
- Examples: RNP 4, RNP 1, RNP APCH.
Application by Flight Phase (Summary)
| Specification | Typical Flight Phase | Lateral Accuracy (95%) | Notes |
|---|---|---|---|
| RNAV 10 (RNP 10) | Oceanic / Remote | 10 NM | Used in NAT HLA. Despite the name "RNP 10", it is an RNAV specification (no alerting). |
| RNP 4 | Oceanic / Remote | 4 NM | Allows reduced lateral separation (e.g., 30 NM or 50 NM). |
| RNP 2 | En-route (Continental and Oceanic/Remote) | 2 NM | Versatile for areas with little ground infrastructure. |
| RNAV 5 | En-route Continental | 5 NM | Used in Europe (B-RNAV). Also for arrivals (STAR) outside 30 NM/MSA. |
| RNAV 2 | En-route Continental, Departures/Arrivals | 2 NM | Common in the USA. |
| RNAV 1 | Terminal (Departures/Arrivals) | 1 NM | P-RNAV in Europe. Requires radar coverage or GNSS. |
| RNP 1 | Terminal (Departures/Arrivals) | 1 NM | Similar to RNAV 1 but with alerting. Used where there is no robust ATS surveillance. |
| RNP APCH | Approach (Initial, Intermediate, Final, Missed) | 0.3 NM (Final) | Standard GNSS approaches (LNAV, LNAV/VNAV, LPV). |
| RNP AR APCH | Approach (Authorisation Required) | 0.3 - 0.1 NM | For complex terrain. Requires specific authorization and training. |
| RNP 0.3 | All (except Oceanic and Final Approach) | 0.3 NM | Specific for helicopters. |
Key Points
- Operational Approval: An approval for a stricter specification (e.g., RNP 0.3) does NOT imply automatic approval for a less strict one (e.g., RNP 4), as functional requirements may differ.
- Designation: The "X" in RNAV X or RNP X indicates the lateral accuracy in nautical miles that must be maintained 95% of the time.
- NAT HLA: Requires RNP 10 (RNAV 10) or RNP 4.