Alex Perry writes: > > I've been looking at the Bendix/King KT 70/71 (transponder) manual and > > plan to start implimenting this instrument. Other than tuning in a > > freq and having it report flight level is there anything else that I > > need to think about? We don't have much in the way of ATC at the > > moment so I'm guessing this instrument will be more cosmetic than > > anything. But, if you are training with an instructor who is playing > > the role of ATC, you can at least go through the motions ... > > (c) Remember that it reports pressure altitude and not any other altitude.
Ok question: >From the KT-70 manual I quote: ALTITUDE DISPLAY - The KT 70 and KT 71 display Flight Level Altitude, marked by the letters "FL" and a number in hundreds of feet, on the left side of the display. For example, the reading "FL 071" corresponds to an altitude of 7,100 feet, referenced to 29.92 inches of mercury at sea level. Flight Level Altitude represents "pressure altitude," and should not be confused with true altitude. Please note that the displayed altitude may not agree exactly with the aircraft's altimeter when flying below 18,000 feet, because encoders are preset to 29.92 inches of mercury. An encoder's alittude transmission is automatically corrected for proper altimeter setting by a ground-based computer, to present the correct altitude to the controller. Ok, so within flightgear, given a 'true' altitude, how can I compute the correct flight-level / pressure-altitude for display on the transponder? Regards, Curt. -- Curtis Olson IVLab / HumanFIRST Program FlightGear Project Twin Cities [EMAIL PROTECTED] [EMAIL PROTECTED] Minnesota http://www.menet.umn.edu/~curt http://www.flightgear.org _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
