Annex C: Performance-Based Navigation Criteria Table (Step 2c)

1. General

1.1 This annex provides guidance on developing the PBN Criteria Table.

2. Rationale and Guidance

2.1 As described in paragraph 4.2.1.b.(3), Step 2c, of the advisory, the PBN Criteria Table identifies the applicable AC 20-138D (reference 3.2.2.a) criteria and means of compliance that will be used to certify the PBN design. The PBN Criteria Table is created by selecting those criteria and means of compliance that correspond to the specific RNP and RNAV capabilities identified in Step 1.

2.2 The PBN Criteria Table will be submitted to the TAA for approval. It is recommended that the table be submitted with the certification plan. However, if necessary, the table may be submitted at a later date.

2.3 Annex D identifies additional technical criteria that the TAA has provided to supplement the criteria in AC 20-138D. The additional criteria should be included in the PBN Criteria Table, as appropriate.

2.4 The criteria in the table will be used to evaluate the PBN design using the appropriate means of compliance identified in the compliance matrix.

2.5 It is recommended that assistance with developing the Criteria Table be requested from DTAES 6 engineering support staff.

2.6 The following should be considered in developing, and obtaining approval of, the PBN Criteria Table:

1. A detailed table is key to the successful certification of a PBN capability. It should be structured around the following information:
   1. the applicable AC 20-138D criteria and the way they were allocated against the requested PBN capabilities defined during Step 1;
   2. the aircraft avionics components to which the approval will apply; and
   3. the operating modes of the navigation and flight management systems for the PBN capabilities defined during Step 1.
2. The PBN Criteria Table should identify the criteria corresponding to each of the discrete PBN capabilities to be certified.
3. Where any criteria have been satisfied by prior certification, and continue to be met by the design change, this may be indicated in the comments section of the Criteria Table and a reference provided in the compliance matrix.
4. The table should include the reasons for excluding any portions of AC 20-138D criteria that would otherwise be expected to apply.
5. AC 20-138D uses mandatory terms, such as “must”, that are only applicable when the means of compliance that the applicant chose to follow are recommended in the AC. The AC also uses ‘non-mandatory’ terms, such as “should” or “recommended”, to identify other acceptable means of compliance that applicants are encouraged to use, but are not mandated. The term “may” is used for optional methods.
6. The TAA recommends that the ‘non-mandatory’ criteria be considered for inclusion in the PBN Criteria Table. The FAA’s reason for including non-mandatory criteria in the AC is to provide an increased design level of safety. For example, the AC recommends that “the course selector of the deviation display be automatically slewed to the RNP computed path.”  This feature is not mandatory for design approval, but it is recommended that it be assessed, and that any conditions that may prevent the criterion from being met be documented in the PBN Design Assessment Report. When a non-mandatory criterion is applied, it should be identified in the Criteria Table as ‘not mandatory.’

2.7 Example of a PBN Criteria Table. Table C-1 is a sample PBN Criteria Table. The table is developed based upon the information available in the certification plan that defines the following:

1. the design to be certified (the currently approved type design and the equipment changes); and
2. the PBN capabilities to be certified, both the current and new PBN capabilities.

NOTES:  
1. Use ICAO Doc 9613, Ed 4, Table II-A-1-1 terminology for navigation specifications and flight phases.
2. The equipment nomenclature and PBN capabilities defined in the certification plan must be identical to the nomenclature and PBN capability phrasing in the PBN Criteria Table.

Table C-1 – Example PBN Criteria Table

AC 20-128D Criterion number 12-8 (Title)

• Column 2 – PBN Capability: n/a
• Column 3 – Flight Phase: n/a
• Column 4 – Equipment Operating Mode: n/a
• Column 5 – Criterion Text: Final Approach Segment Step-Down Fixes in Navigation Databases
• Column 6 – Compliance Technique: n/a
• Column 7 – Compliance Notes: n/a
• Column 8 – Results (Met/Not met)
• Column 9 – Comments

AC 20-128D Criterion number 12-8 (a)

• Column 2 – PBN Capability: n/a
• Column 3 – Flight Phase: n/a
• Column 4 – Equipment Operating Mode: n/a
• Column 5 – Criterion Text: […] the database must include all named waypoints that make up the instrument approach procedure except for final approach segment step-down fixes. Showing step-down fixes on a vertical profile display can enhance flight crew situation awareness, but can also complicate installation issues (see paragraphs 12-8.b through 12-8.d).[...]
• Column 6 – Compliance Technique: n/a
• Column 7 – Compliance Notes: This Criteria Table constitutes contact with the DND certification authority. Approval requested for the onboard navigation database to contain step-down fixes.
• Column 8 – Results (Met/Not met)
• Column 9 – Comments

AC 20-128D Criterion number 12-8 (b)

• Column 2 – PBN Capability: RNP APCH Part A (GNSS); RNP APCH Part B (GPS SBAS)
• Column 3 – Flight Phase: All approach segments
• Column 4 – Equipment Operating Mode: See PBN Capability Description
• Column 5 – Criterion Text: Equipment manufacturers providing final approach segment step-down fixes in their onboard navigation databases for RNAV (GPS) approach procedures must either provide a method to remove them or provide an installation limitation for cockpit configurations that cannot properly support them (i.e., define the requirements in the installation instructions/manual).
• Column 6 – Compliance Technique: Inspection
• Column 7 – Compliance Notes: The Flight Management System (FMS) installation instructions contain criteria for the cockpit configuration. Each MFD will be assessed using the criteria in the FMS installation instructions.
• Column 8 – Results (Met/Not met)
• Column 9 – Comments

AC 20-128D Criterion number 12-8 (c) (excluding sub-paras)

• Column 2 – PBN Capability: RNP APCH Part A (GNSS); RNP APCH Part B (GPS SBAS)
• Column 3 – Flight Phase: All approach segments
• Column 4 – Equipment Operating Mode: See PBN Capability Description
• Column 5 – Criterion Text: […] The airworthiness applicant must ensure the displayed RNAV(GPS) approach is in the primary field of view, in the proper sequence, unambiguous, and does not create detrimental clutter.
• Column 6 – Compliance Technique: Inspection
• Column 7 – Compliance Notes: Same as for Criterion number 12-8 (b) above
• Column 8 – Results (Met/Not met)
• Column 9 – Comments

AC 20-128D Criterion number 12-8 (c)(2)

• Column 2 – PBN Capability: RNP APCH Part A (GNSS); RNP APCH Part B (GPS SBAS)
• Column 3 – Flight Phase: All approach segments
• Column 4 – Equipment Operating Mode: See PBN Capability Description
• Column 5 – Criterion Text: When installing equipment with final approach segment step-down fixes in the onboard navigation database, the display integration must:
  • Be accessible and readable by all required flight crewmembers;
  • Cleary depict and label the aircraft’s track;
  • Clearly label displayed waypoints, fixes and numeric information with sufficient detail to enable a pilot to discern a step-down fix from other fixes on a procedure.
• Column 6 – Compliance Technique: Inspection
• Column 7 – Compliance Notes: Same as for Criterion number 12-8 (b) above
• Column 8 – Results (Met/Not met)
• Column 9 – Comments

AC 20-128D Criterion number A12-8 c (3) First criterion

• Column 2 – PBN Capability: RNP APCH Part A (GNSS); RNP APCH Part B (GPS SBAS)
• Column 3 – Flight Phase: All approach segments
• Column 4 – Equipment Operating Mode: See PBN Capability Description
• Column 5 – Criterion Text: The suggested optimum implementation is showing final approach segment step-down fixes for LNAV and LP approaches, but not showing final approach segment step-down fixes during an LNAV/VNAV or LPV approach.
• Column 6 – Compliance Technique: Flight Test
• Column 7 – Compliance Notes: Final approach segment step-down fixes are displayed during LNAV/VNAV approaches. They are not displayed during an LPV approach.
• Column 8 – Results (Met/Not met)
• Column 9 – Comments

AC 20-128D Criterion number 12-8 c (3) Second criterion

• Column 2 – PBN Capability: RNP APCH Part A (GNSS); RNP APCH Part B (GPS SBAS)
• Column 3 – Flight Phase: All approach segments
• Column 4 – Equipment Operating Mode: See PBN Capability Description
• Column 5 – Criterion Text: […] When displaying distance/bearing/track to a step-down fix on the LPV final approach segment (i.e., after crossing the final approach fix), the equipment must also provide a readily available, clear, unambiguous indication of distance/bearing/track to the LTP/FTP. Due consideration should be given to the cockpit configuration and display capabilities during the airworthiness approval process.
• Column 6 – Compliance Technique: Flight Test
• Column 7 – Compliance Notes: The MAP page shows the step-down fix name, distance and track in a callout box attached to the fix. The feature is not selectable. Non-interference with LPV path construction will be demonstrated in flight.
• Column 8 – Results (Met/Not met)
• Column 9 – Comments

AC 20-128D Criterion number 12-8 (d)

• Column 2 – PBN Capability: RNP APCH Part A (GNSS); RNP APCH Part B (GPS SBAS)
• Column 3 – Flight Phase: All approach segments
• Column 4 – Equipment Operating Mode: See PBN Capability Description
• Column 5 – Criterion Text: […] airworthiness applicants must include language for a limitation in the AFM(S)/RFM(S) (or equivalent documentation) requiring the flight crew to use the primary barometric altimeter to comply with a final approach segment step-down fix altitude restriction during an LNAV, LP, or non-ILS conventional approach. […]
• Column 6 – Compliance Technique: AFM
• Column 7 – Compliance Notes: This is a limitation in the current AFM.
• Column 8 – Results (Met/Not met)
• Column 9 – Comments

TAA Advisory 2019–05, Additional Technical Criteria

• Column 2 – PBN Capability: RNP APCH Part A (GNSS); RNP APCH Part B (GPS SBAS)
• Column 3 – Flight Phase: All approach segments
• Column 4 – Equipment Operating Mode: See PBN Capability Description
• Column 5 – Criterion Text:   5. Inoperative Equipment. The effect of inoperative equipment on the PBN capability must be assessed and if necessary addressed by AFM limitations, or the MEL.
• Column 6 – Compliance Technique: Inspection
• Column 7 – Compliance Notes: Display of step-down fixes will be assessed with any one MFD inoperative.
• Column 8 – Results (Met/Not met)
• Column 9 – Comments