RNAV and RNP Operations — AIM 5-5-16 Explained

AIM Text

Pilot.
1. If unable to comply with the requirements of an RNAV or RNP procedure, pilots must advise air traffic control as soon as possible. For example, “N1234, failure of GPS system, unable RNAV, request amended clearance.”
2. Pilots are not authorized to fly a published RNAV or RNP procedure (instrument approach, departure, or arrival procedure) unless it is retrievable by the procedure name from the current aircraft navigation database and conforms to the charted procedure. The system must be able to retrieve the procedure by name from the aircraft navigation database, not just as a manually entered series of waypoints.
3. Whenever possible, RNAV routes (Q- or T-route) should be extracted from the database in their entirety, rather than loading RNAV route waypoints from the database into the flight plan individually. However, selecting and inserting individual, named fixes from the database is permitted, provided all fixes along the published route to be flown are inserted.
4. Pilots must not change any database waypoint type from a fly-by to fly-over, or vice versa. No other modification of database waypoints or the creation of user-defined waypoints on published RNAV or RNP procedures is permitted, except to:
  1. Change altitude and/or airspeed waypoint constraints to comply with an ATC clearance/instruction.
  2. Insert a waypoint along the published route to assist in complying with ATC instruction, example, “Descend via the WILMS arrival except cross 30 north of BRUCE at/or below FL 210.” This is limited only to systems that allow along-track waypoint construction.
5. Pilots of FMS-equipped aircraft, who are assigned an RNAV DP or STAR procedure and subsequently receive a change of runway, transition or procedure, must verify that the appropriate changes are loaded and available for navigation.
6. For RNAV 1 DPs and STARs, pilots must use a CDI, flight director and/or autopilot, in lateral navigation mode. Other methods providing an equivalent level of performance may also be acceptable.
7. For RNAV 1 DPs and STARs, pilots of aircraft without GPS, using DME/DME/IRU, must ensure the aircraft navigation system position is confirmed, within 1,000 feet, at the start point of take-off roll. The use of an automatic or manual runway update is an acceptable means of compliance with this requirement. Other methods providing an equivalent level of performance may also be acceptable.
8. For procedures or routes requiring the use of GPS, if the navigation system does not automatically alert the flight crew of a loss of GPS, the operator must develop procedures to verify correct GPS operation.
9. RNAV terminal procedures (DP and STAR) may be amended by ATC issuing radar vectors and/or clearances direct to a waypoint. Pilots should avoid premature manual deletion of waypoints from their active “legs” page to allow for rejoining procedures.
10. RAIM Prediction: If TSO-C129 equipment is used to solely satisfy the RNAV and RNP requirement, GPS RAIM availability must be confirmed for the intended route of flight (route and time). If RAIM is not available, pilots need an approved alternate means of navigation.
  
  REFERENCE-
  
  AIM, Para 5-1-16, RNAV and RNP Operations.
11. Definition of “established” for RNAV and RNP operations. An aircraft is considered to be established on-course during RNAV and RNP operations anytime it is within 1 times the required accuracy for the segment being flown. For example, while operating on a Q-Route (RNAV 2), the aircraft is considered to be established on-course when it is within 2 NM of the course centerline.
  NOTE-
  1. Pilots must be aware of how their navigation system operates, along with any AFM limitations, and confirm that the aircraft's lateral deviation display (or map display if being used as an allowed alternate means) is suitable for the accuracy of the segment being flown. Automatic scaling and alerting changes are appropriate for some operations. For example, TSO-C129 systems change within 30 miles of destination and within 2 miles of FAF to support approach operations. For some navigation systems and operations, manual selection of scaling will be necessary.
  2. Pilots flying FMS equipped aircraft with barometric vertical navigation (Baro-VNAV) may descend when the aircraft is established on-course following FMS leg transition to the next segment. Leg transition normally occurs at the turn bisector for a fly-by waypoint (reference paragraph 1-2-1 for more on waypoints). When using full automation, pilots should monitor the aircraft to ensure the aircraft is turning at appropriate lead times and descending once established on-course.
  3. Pilots flying TSO-C129 navigation system equipped aircraft without full automation should use normal lead points to begin the turn. Pilots may descend when established on-course on the next segment of the approach.

Source: FAA Aeronautical Information Manual · current edition · paragraph 5-5-16.

The short answer

This AIM section is FAA advisory guidance on pilot and ATC roles for RNAV and RNP operations. It explains database-retrievable procedures, permitted waypoint modifications, equipment requirements for RNAV 1 DPs and STARs, RAIM prediction, and the definition of "established on-course" — supporting RNAV/RNP navigation under 14 CFR Part 91.

Research Notes

Common Questions

Can I manually enter waypoints instead of loading a published RNAV procedure?

No. The AIM advises pilots are not authorized to fly a published RNAV or RNP procedure unless it is retrievable by the procedure name from the current aircraft navigation database — not just a manually entered series of waypoints. RNAV routes (Q- or T-routes) should be extracted in their entirety where possible, though selecting individual named fixes is permitted provided all fixes along the published route are inserted.

When is an aircraft considered established on-course during RNAV or RNP operations?

Per this section, an aircraft is established on-course anytime it is within 1 times the required accuracy for the segment being flown. For example, on a Q-Route (RNAV 2), the aircraft is established when within 2 NM of the course centerline.

What waypoint modifications are allowed on a published RNAV or RNP procedure?

The AIM says pilots must not change a database waypoint from fly-by to fly-over or vice versa, and no other modification or user-defined waypoints are permitted — except to change altitude/airspeed constraints to comply with an ATC clearance, or to insert an along-track waypoint to assist with ATC instructions on systems that allow along-track waypoint construction.

5-5-16. RNAV and RNP Operations