James Turner writes: > Just one thing : when I get to the KLN-89b, I'm going to need support > for optionally back-driving the instruments from the GPS's output (this > couple if required in order for the installation to be certified for > GPS precision approaches). Such operation is usually done via simple > NAV/GPS toggle switch on the panel somewhere. I *think* the only thing > I need to drive is CDI deflection, since you can't get GS from a GPS > approach (please, someone, correct me if I'm wrong here, all I have to > go on is Fly! and the Bendix-King PDF manual..)
Precision GPS approaches are not yet approved, at least not in Canada or the U.S., but they're on the table. For now you're correct -- an IFR GPS will not drive a glidescope. Note that the KLN 89B can show a CDI on its LED panel, but for IFR certification a GPS is required to drive an external, left-right indicator (often a shared VOR gauge). Sometimes an external annunciator is also required for IFR cert, depending on whether the GPS is installed inside the normal panel scan range or not. If the GPS if VFR-only, then none of this stuff is required (but you cannot use it for primary RNAV or for GPS approaches). > In larger aircraft, I assume there's other things that can be > back-drive, even before you get up to a full PFD / NAV display. So, > I'd just like to establish how we differentiate between 'signal > output from the radio' versus 'signal input to the HSI instrument', > so that someone can trivially add the toggle switch to their > panels. We'll probably need some kind of a plug-and-play system, where you configure each instrument with its inputs and outputs. This could be handled in C++ code or in the XML instrument config files. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
