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ILS Categories

Asked by: 5563 views Instrument Rating

The lowest authorized ILS minimums, with all required ground and airborne systems components operative started with Category I, which has Decision Height (DH) of 200 feet and Runway Visual Range (RVR) 2,400 feet.

The (DH) on ILS RWY 31 at ST. AUGUSTINE is 258 which is above 200 feet and Vis of ¾ s.m (RVR) 4000 feet. In that case, what is the category for this ILS approach?

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3 Answers

  1. Best Answer


    John D Collins on Nov 24, 2013

    There are three categories for precision approaches, Category I, II, and III with some subdivisions. Category I precision approaches have a DH of 200 feet or higher and a visibility requirement as low as 1800 RVR if the runway meets certain conditions. The most common Category I minimums have a DH of 200 feet and 1/2 mile visibility (RVR 2400). The ILS or LOC/DME RWY 31 at St Augustine is a category I approach. It has a higher DH because of obstacle issues and a higher visibility requirement because it lacks a qualifying approach light system.

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  2. Mark Kolber on Nov 24, 2013

    >> what is the category for this ILS approach?

    John, I may be wrong on this but aren’t Category II and II approaches identified as such in the title of the approach? IOW, if there’s no designation, it’s Category I.

    (There may be a designation even for Category I if, for example its a Special Aircrew Category I approach)

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  3. Wes Beard on Nov 24, 2013

    Mark,
    You are correct. Category II and III approaches are labeled as such in the approach title. All instrument rated pilots are able to perform category I approaches unless it is a SAAAR (special aircrew / aircraft authorization required) approach. Most SAAAR approaches deal with RNP (required navigational performance) approaches.

    Category II and II approaches require aircrew training and the airplane has to have the extra equipment required by that category.

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