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Required equipment to fly RNAV (GPS) approach

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Refer to the Phoenix Deer Valley (DVT) RNAV (GPS) RWY 25L approach plate.

In the top  margin, adjacent to the textual missed approach instructions is the notation: "DME/DME RNP-0.3 NA." 

I fully understand what this restriction means (e.g., unsuitable/unavailable DME facilities).

However, since properly certified GPS equipment capable of delivering RNP 0.3 accuracy is a requirement to fly this approach, under what circumstances would DME/DME derived RNP 0.3 ever be an issue?

In other words, the fact that this annotation (DME/DME RNP 0.3 NA) is shown on the approach plate at all suggests that if it were not for this restriction an aircraft that is not GPS equipped, but could nevertheless deliver RNP 0.3 accuracy,  would be legally allowed to fly this approach.  For example, an aircraft that had a  FMC (Flight Management Computer) system deriving position information from DME/DME/IRU could use the LNAV minimums (assuming the DME/DME RNP 0.3 NA annotation was not on the approach plate).

I guess I'm puzzled as to why this DME/DME RNP .03 NA restriction is even on the approach plate since GPS equipment  capable of delivering RNP 0.3 accuracy is mandatory based on the approach plate title ( RNAV (GPS) RWY 25.

2 Answers



  1. John D Collins on May 03, 2017

    This note is the result of charting instructions found in National Policy, SUBJ: Flight Procedures and Airspace, FAA Order 8260.19G, section 4-6-10:

    4-6-10. Additional documentation with Baro-VNAV (LNAV/VNAV and RNP), GBAS, and/or WAAS Instrument Approach Procedures.

    e. For RNAV (GPS) procedures where DME/DME RNP-0.3 is not authorized, use “Chart note: DME/DME RNP- 0.3 NA.” Where DME/DME RNP-0.3 is authorized, use “Chart note: DME/DME RNP-0.3 Authorized.” Where DME/DME RNP-0.3 is authorized only when required facilities are necessary for proper navigation solution, use “Chart note: DME/DME RNP-0.3 Authorized; ABC and XYZ DMEs must be Operational.” For RNAV (RNP) procedures, the use of GPS is required; use “Chart note: GPS Required.”

    It is also covered in 8.6.6 Notes:

    o. Where DME/DME RNP-0.3 is not authorized, use “Chart Note: DME/DME RNP-0.3 NA.” Where DME/DME RNP-0.3 is authorized, use “Chart note: DME/DME RNP-0.3 Authorized.” Where DME/DME RNP-0.3 is authorized only when required facilities are necessary for proper navigation solution, use “Chart note: DME/DME RNP-0.3 Authorized; ABC and XYZ must be Operational.”

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  2. R. Anderson on May 03, 2017

    Hello John,

    Thanks for the quick response. I am familiar with these charting requirements and your research is helpful.

    However, I was just wondering if anyone might have an idea of the logic behind having the notation (DME/DME RNP 0.3 NA) for an RNAV (GPS) approach that would never incorporate DME/DME derived RNP 0.3 since GPS is always required (for the Phoenix Deer Valley (DVT) RNAV (GPS) RWY 25L approach).

    Is there a possibility that DME/DME RNP 0.3 could be authorized for the DVT approach in question instead of the charted/legal requirement for GPS equipment to be the source of the required RNP 0.3 accuracy?

    When something is charted as being NA (Not Authorized) that, seemingly, could never be authorized in the first place, my confidence as to whether or not I understand the basic requirements is negatively impacted.

    Thanks again,

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