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    Re: Great Circle Course via calculator & HO 208
    From: Antoine Couëtte
    Date: 2016 Oct 6, 22:31 -0700

    Re: http://fer3.com/arc/m2.aspx/Great-Circle-Course-via-calculator-HO-208-FrankReed-oct-2016-g36790

    Frank, you recently wrote:

    "but they apparently chose the trivially easy road: the great circle route generated by their onboard flight-planning computer. Press the button and follow the blinking red dot... "

    Since I might not understand you statement exactly as you intended it, may I then suggest the following little clarification ?

    Both over Land and over the Oceans, Pilots just do not plan Great Circle Route from Present Airport Position towards arbitrarily and conveniently chosen distant points. On ground they have to carefully program their Navigation Computers alongside (portions of) published routes, i.e. through pre-determined sequences of waypoints as per their "Acknowledged Flight Plan" acknowledged and accepted by Air Traffic Center (ATC).

    Once airborne, and only if and when cleared by ATC Pilots can delete intermediate waypoints and fly towards distant points down the flight path, or towards new points not initially programmed on ground.

    Under their uncertain War environment, necessarily both Pilots very carefully filed their Flight Plan in full accordance with approved routes, they loaded their navigation computers whith extra care and caution and once airborne they did not take the risk of recklessly flying unapproved shortcuts on their own. IMOH that possibility should be totally discarded unless conclusively and 100% proven.

    Having said that - and I agree 100% with you here - the Aircraft onboard computers do indeed follow Great Circles and will correct for any perturbation due to the environment. At Pilots' request, they can also fly "Offset Routes" specified/defined under the form of "Right/Left xx crosstrack miles" from ATC published routes.


    PS: Since you ventured on your own onto this totally off-topic subject, may I just remind that - as of to-day 07 Oct 2016 -  only the Missile type has most recently and conclusively been identified as a russian-made one, but we are still very far from being 100% certain that this missile was shot by pro-Russian forces. "Which Force" actually pulled the trigger still remains an open and very serious question.

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