Performance-Based Navigation (PBN) – One Year Later
Performance-Based Navigation (PBN) codes were introduced with the International Civil Aviation Organization (ICAO) 2012 change that took effect on November 15, 2012. With that change came confusion and lots of questions. Let’s look at what PBN is, resources to use in order to determine which PBN codes to display in the Flight Plan (FPL), some changes that occurred over the year, and some answers to common questions.
NOTE: This information mostly pertains to U.S.-registered aircraft. For specific questions regarding your state of registry, please communicate with the governing authorities that issue your authorizations or with your aircraft manufacture.
The following is an overview of what you need to know:
1. What PBN means
In 2008, there was an official name change made from "Required Navigation Performance" to "Performance-Based Navigation" when ICAO published DOC 9613 Edition 3.
The PBN concept specifies that aircraft RNAV system performance requirements be defined in terms of the accuracy, integrity, availability, continuity and functionality that are needed for the proposed operations in the context of a particular airspace concept. The PBN concept represents a shift from sensor-based to performance-based navigation. Performance requirements are identified in navigation specifications, which also identify the choice of navigation sensors and equipment that may be used to meet the performance requirements. These navigation specifications are defined at a sufficient level of detail to facilitate global harmonization by providing specific implementation guidance for states and operators.
Source: ICAO DOC 9613, Edition 3
2. How to determine which PBN codes to select
When operating under Federal Aviation Administration (FAA) Operations Specifications (Ops Specs) or M-Specs, it is very easy to determine which PBN codes you would select for your FPL. After contacting your aircraft manufacturer to get assistance in identifying what your aircraft is certified for, then you may visit the FAA’s ICAO Flight Plan Guidance website where you will find a link to the Operational Approval Guidance Table. Use this table as a guide to identify which PBN codes will apply to your operations. You may also visit the FAA’s Performance-Based Flight Systems Branch.
NOTE: Some Ops Specs may indicate the required sections under different numbers. Contact your local Flight Standards District Office (FSDO) if you have any questions or need clarification in interpreting your documentation.
3. PBN codes for private non-revenue (Part 91, except subpart K)
For these operations, you may still use the Operational Approval Guidance Table or visit the FAA’s Performance-Based Flight Systems Branch; however, it is a little trickier, and a little more leg work is probably required, as not all areas are covered by a letter of authorization (LOA). Digging into your aircraft flight manual (AFM) and some advisory circulars (as noted in the Guidance Table described above) may be required. Once again, verify the limitations in your documents, and if you have questions, your number one resource should be your aircraft manufacturer or local FSDO.
4. Changes over the last year
The FAA’s use of PBN codes
Since the release of PBN codes last year, the use of RNAV10 (A1) and RNP4 (L1) was almost immediate, but the transition into the RNAV2 and RNAV1 codes was not.
Starting in 2008, operators became familiar with U.S. RNAV codes that were inserted into Item 18 of the ICAO portion of the FPL – the Navigation (NAV/) field. Examples for the NAV/ field are RNVD1E2A1 or RNVE2 or RNVE99, etc. Starting in August of 2013, the use of these U.S. RNAV codes are no longer required to identify RNAV capabilities.
The FAA states that in order to receive RNAV procedures and routes, operators must do the following: Use the FAA ICAO flight plan format to file a flight plan, place an "R" in Item 10a, and specify the PBN/ codes in Item 18. If filing a domestic plan, the flight will not be eligible for RNAV procedures. Along with this change, you are no longer required to file the U.S. RNAV codes in Item 18 – NAV/. However, operators can use the NAV/ to omit specific PBN procedures.
Which codes qualify you for RNAV operations in the U.S.?
To qualify for an RNAV SID or STAR, RNAV1 with either GNSS or DME/DME/IRU is required. The appropriate PBN codes are: PBN/D1, PBN/D2 and/or PBN/D4. To qualify for the RNAV Q- Routes, RNAV2 with either GNSS or DME/DME/IRU is required. The appropriate PBN codes are PBN/C1, PBN/C2 and/or PBN/C4.
5. Common questions with regards to PBN
What is the difference between RNAV and RNP designations?
These are essentially the same thing, but RNP carries a higher standard because it’s performance levels require monitoring and alerting systems that the RNAV designation does not.
If I am RNAV1, am I automatically authorized for the higher performance levels?
The idea is that if you are RNAV1, you are automatically authorized for operations at the RNAV2, RNAV5 or RNAV10 performance levels. This is not true. Each performance level carries its own set of standards, and authorization is issued separately for each designation.
If I indicate O1 on the FPL, do I need to indicate the codes for the higher performance levels?
Each Air Navigation Service Provider (ANSP) around the world may look for different codes in the PBN/ field. One descriptor will not cover for another (except in the case of RNP4 and RNAV10). So in order to be sure you are providing each ANSP as much of your actual capabilities as possible, be sure to select all applicable codes.
I have a (insert your aircraft type here.) Can I just indicate the same thing as another operator of the same type?
No. Not all operators may have the authorization or training to meet the standards for each of the different possibilities with PBN. Also, some aircraft may have different modifications or upgrades that allow owners to select different PBN codes, whereas other operators may not meet the proper standards.
What does "All Sensors" mean?
For RNAV5, "All Sensors" means that if you meet the standards for B2, B3, B4 and B5, then you select only B1. For RNAV2, RNAV1 and Basic RNP1, if you meet the standards for GNSS, DME/DME and DME/DME/IRU equipment, then you select "All Sensors."
6. Other tips to note
Keep in mind that ICAO documentation specifies that not only are you to display what equipment and/or capabilities the aircraft has, but these must also be serviceable, the crew must be properly trained, and you must have the proper state authorizations where applicable. Operators may take that extra step in identifying in their operating specifications/MEL/procedures when one of these pieces of equipment is missing and how that would affect the information displayed in Item 10 and Item 18 of the FPL.
With all the alphabet soup of regulations, especially when flying in U.S. airspace, be sure that if you communicate with air traffic control (ATC) about one of the flight plan codes, you are very descriptive as to which code you are talking about. Some examples may be ICAO Item 10a code, ICAO Item 10b code, ICAO Item 18 PBN code, ICAO transponder code, and FAA domestic code.
Also, your 3rd-party provider may be able to answer many of these questions, but your best two resources for this information outside your internal operations or mechanic should be those entities that issue the authorizations for your operations and the aircraft manufacturer.
Do your homework in advance, as for some operators, this is something that will require time and effort in order to obtain the answers you are seeking. Indicating or not the correct descriptor in Item 18 PBN/ of the FPL could cause unnecessary delays in putting together your flight plan. Without the proper indications, you can expect delays in departure as well as unfavorable flight levels, speeds, or even re-routes.
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