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2 Answers

Alternates?

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Instrument Rating

I'm studying for my IFR rating. I'm confused by the black triangle with the white "A" inside, found on some approach charts.

What does it mean? I know what the trouble "T" is, but cannot find a definitive answer for the  triangle A. I know it has to do with alternates...

Is is it for that specific approach plate that its on? Or is it for the airport? 

Example: McMinville, Oregon (KMMV) ILS or LOC 22

2 Answers



  1. jeff on Mar 08, 2015

    Its means there are “Alternate Minimums” which apply in using that airport/approach as an alternate. Normally, in order to file an airport as an alternate (if required based on the 1/2/3 rule), the weather at that airport at the estimated time of arrival must be at least 600-2 if the airport has a precision approach and 800-2 if the airport has a non-precision approach. If there airport requires minimums which differ from this then there will be a black triangle with the “A” inside of it as you have found. Hopefully that makes that clear for you.

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  2. John D Collins on Mar 08, 2015

    The black triangle with the A is used for two purposes. If it is followed by NA, then the procedure is Not Authorized to be used for filing purposes of an alternate. If the A symbol is not displayed, then the approach may be used as an alternate using the standard alternate minimums. If the A symbol is by itself, it means that you must read the notes in the alternate section of the approach chart booklet. The notes may specify other conditions that must be taken into account in order for the approach to be used as an alternate. The other conditions might be non standard minimums or might require that a tower be open or that local weather has to be available, or ….

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