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    Re: Question for pilots.
    From: Gary LaPook
    Date: 2014 Mar 17, 21:39 -0700
    Radar is limited to the radar horizon, about 1.44 times the square root of the height of the antenna plus 1.44 times the height of the plane.  From 35,000 feet the radar horizon is 230 nautical miles away. The radar detection range might be further limited by the power output of the radar transmitter based on the fourth power of the range, from the standard radar range formula. If the lane descended to 5,000 feet then the radar horizon was limited to about 90 NM. When I flew the ocean, separation of planes was based on HF position reports given by the pilots in this format:   http://members.home.nl/7seas/radcalc.htm

    The standard format for position reports is:

    "Gander radio this is Cessna November one six two one seven;
    forty west, forty three thirty five north at 2015 ;
    flight level one zero zero;
    Estimating thirty five west, forty one twenty north at 2230 ;
    Mike next;

    This is the same format over the U.S. if radar is inop.

    The time (Zulu of course) of the position is obviously an important element of the report and is the time at the position, not the time of the radio message which might be a bit latter depending on HF propagation conditions.

    As far as I know this is still done but the position reports are now sent over a satellite link instead of HF. 


    From: Lu Abel <luabel@ymail.com>
    To: garylapook@pacbell.net
    Sent: Monday, March 17, 2014 1:51 PM
    Subject: [NavList] Re: Question for pilots.

    There was a discussion of offshore tracking on one of the (US) national news programs yesterday and when asked about a knowledgeable hijacker disabling satellite tracking (as the MN370 hijackers apparently did with their ground transponder), the aviation expert being interviewed said "unfortunately, there's always a circuit breaker somewhere that someone with sufficient expertise could throw ..." 

    From: Richard B. Langley <lang---.ca>
    To: luabel{at}ymail.com
    Subject: [NavList] Re: Question for pilots.

    In the future, we might not have to rely on radar. NAV CANADA has entered into a joint venture with Iridium Communications, called Aireon, which will expand air traffic surveillance to the entire planet by installing ADS-B receivers on Low Earth Orbit (LEO) satellites. The plan is to use the Iridium NEXT satellites.
    I guess such a system could also be turned off on an aircraft unless it is made tamper-proof. But it would likely have a circuit breaker somewhere.

    View and reply to this message: http://fer3.com/arc/m2.aspx?i=127243

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