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4 Answers

Locating aircraft specifications required by approach plate.

Asked by: 570 views Instrument Rating

If an approach plate identifies a GPS fix as "RNAV 1-GPS REQD", how would I determine whether or not my aircraft meets that requirement? A similar question would be about when an approach plate refers to RNP-0.3. I have a general understanding of what those values mean, but not how I would find whether or not an aircraft meets those requirements. Is that information that I would find in the POH? I'm asking from the standpoint of a student preparing for an instrument rating oral exam.

4 Answers



  1. Wes Beard on Sep 05, 2017

    If your GPS is approved under TSO c129 it is approved for RNAV 0.3, 1 and 2. Approach sensitivity, SID/STAR sensitivity and en-route sensitivity respectively.

    RNP 0.3 is a newer specification and very few GA jets have an installation approved for those operations. Read the manual that came with your GPS. It will tell you what it is approved for.

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  2. John D Collins on Sep 06, 2017

    Wes,

    A TSO C129 GPS is not likely to be approved for RNAV 1 RNAV SID and STAR, although a few are such as the GNS430 and G1000 systems. All TSO C145/146 GPS systems are approved for RNAV 1 SID/STAR. On an RNAV (GPS) approach, RNAV 1 is also used for terminal route legs, but this is all covered under the “RNP Approach” specification and not under the RNAV 1 specification for RNAV SID/STAR. Basically, if the approach is named RNAV (GPS), one may fly all the legs on the procedure. Although the PBN code of S1 or S2 applies to these procedures, these codes are not needed or used in the US if G is specified in the ICAO equipment field. The basic rule is if you find the RNAV SID/STAR in the database, then the GPS is approved to fly the RNAV SID/STAR. Reference documents are AC 90-100A and AC 90-105A.

    RNP 0.3 is a helicopter specification, but RNAV (RNP) approaches, all which require explicit FAA crew and equipment authorization and are not found in the database of a GA TSO C129/145/146 GPS, will also have final approach legs which may specify an RNP value such as 0.3 or 0.1. Equipment that qualifies to fly these procedures is only found in high end corporate and airline turbojet aircraft. The ICAO PBN code is T1 or T2 depending on if the aircraft and crew are approved to fly RF legs.

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  3. Troy Tricker on Sep 07, 2017

    Thank you! The specific plane I fly is a C-172 with a G1000 that has a non-WAAS GPS, although I was wanting to understand from a more general standpoint where to find the information. So it sounds like the answer is to look in the POH/AFM for the aircraft. This plane is a rental and I have not been back to the airport to look through those, but based on a search, I believe this system is going to qualify as TSO-C129a. If I’m interpreting a matrix I found on the FAA website correctly, it does qualify as a RNAV-1 capable GPS.

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  4. John D Collins on Sep 07, 2017

    Troy,

    The G1000 non WAAS version does qualify to fly RNAV SID/STAR procedures. I would code the following:

    ICAO Equipment: S, G, R
    ICAO Surveillance: C
    ICAO PBN: B2, C2, D2

    Not all GPS systems have an AFMS that was written after all this PBN stuff came into vogue, but you can look them up in this document referenced in AC 90-100A:

    https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/afx/afs/afs400/afs470/media/AC90-100compliance.pdf

    Look on page 7 of the Garmin section and see the notes regarding the G1000 system (pdf page 62). If you also look at page 2 of the Honeywell section for a popular different GPS, the KLN94 (pdf page 68) you will note that it is not approved for flying the RNAV SID/STAR.

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