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Instrument Approach Chart symbology

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General Aviation, Instrument Rating

Some IAP's have a negative D above the runway sketch. I know what it means. Why do some approaches have the symbol while others do not?

2 Answers



  1. Jeff Baum on Oct 13, 2023

    From the Aeronautical Chart User Guide

    “Runway Declared Distance Information

    Runway declared distance information when available will be indicated by [“negative D”] and is shown to the right of the airport elevation in the sketch box. Declared distances for a runway represent the maximum distances available and suitable for meeting takeoff and landing distance performance requirements.”

    If there is no “negative D”, the declared distance information is not available. As an example U68 does not have any declared distance information listed in the Chart Supplement while KCOD does.

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  2. Mark Kolber on Oct 13, 2023

    RDD means that something other than the full length of the runway is usable. For a simple example, runway 9/27 is 5000′ long. But 9 has a 500′ displaced threshold. There would be a negative D in the chart, indicating you should check the Chart Supplement. The CS would show a TODA of 5000′ for runway 9 but a LDA of only 4500′.

    If there is nothing that prevents the use of the entire runway for takeoff or landing, you would not see the symbol.

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