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5 Answers

green dot

Asked by: 3421 views Commercial Pilot, Instrument Rating

hello guys. what is 85 in green dot formula meant? (gw/1000x2)+85 thanks.

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5 Answers



  1. KDS on Aug 24, 2018

    I believe you are asking what a specific code that you found in the Chart Supplement means. That is a green book for airports in CONUS. I cannot answer your specific question, but you should be able to find the answer by looking in the AIRPORT/FACILITY DIRECTORY LEGEND, which is in the front of each of the books.

    If you can provide more detail (i.e., what airport you see that has that code), we might be able to better assist you.

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  2. salem91 on Aug 24, 2018

    KDS, that is not what i meant. The 85 that im asking is the calculation formula for green dot speed of A320. (gross weight of aircraft over 1 thousand times 2) plus 85.

    Is the 85 a constant? If it’s a constant, what does it stands for?

    btw thanks for replying. I do appreciate it.

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  3. KDS on Aug 26, 2018

    Okay. I took “dot” to mean Department of Transportation” and I was trying to put that together.

    I’ll take a guess that you may be in a type rating course at the current time. If so, the person who is the walking encyclopedia is your instructor. Best to ask the instructor.

    If not, try doing a Google search for “green dot” and “Airbus” or such as that. I did and was overwhelmed with the number of articles written on the subject. Some of them were very lengthy and scholarly.

    I’m afraid I have to confess to being more of a simple guy than a theorist. I just stick with what someone once told me when describing the V bars of a flight director, and that was to “put your rocket in the pocket and keep it there”. So, I suspect your question may be a bit over my head. However, we’ll all be happy to read the answer if and when you do come across it.

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  4. Brian on Sep 01, 2018

    In unsure this would be the forum for such a question. You might try airline pilot central or jetcareers technical forum. I fly the 170/175, sadly I know nothing of the 320s green dot calculation. For us it’s 1.3g stall or roughly a 48 degree bank at low altitudes and in the flight levels it’s drift down speed. Useless when ice speeds are used. I don’t have any other transport experience to pull off of, but I’m certain there are many on either of the forums I mentioned that can help you out.

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  5. Brian on Sep 01, 2018

    i guess I should have checked out the question a bit more closely. Woops! The 85 is a conversion factor. Since you’re going from weight in some units to velocity in knots it is unlikely that they would play nicely together. In other words, the 85 allows the answer you get to be in knots; a usable unit for a pilot.

    Similar conversions are used all throughout our field. For instance rate of climb is a function of power available minus power required multiplied by 33,000 and then all of this divided by weight. 33,000 concerts all the weight and power units nicely into feet per minute.

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