On 22 Feb 2017, at 7:32 PM, Justin Couch <[email protected]> wrote: > If we look at a 10 year lifespan for equipment, then the horizon of the > adoption of ADS-B is the interesting bit to us, rather than equipment cost.
As of the current date: Any new aircraft placed on the Australian register which expects to fly in class E or class C airspace or in any class of airspace above 10,000' must have a mode-S transponder. (There are exemptions for aircraft which don’t have an electrical system capable of continuously powering a transponder. Given the power requirements of modern kit, it’s debatable whether a glider still qualifies for the exemption, but CASA are happy to let it slide for now) Any new transponder fitted to an Australian aircraft which is intended to operate in class E or class C airspace must be mode-S. Any aircraft which is flying IFR in any airspace must have a mode-S transponder which broadcasts ADS-B, unless they’re being used for private flight only, in which case there’s an extension. The extension came so late that much of the Australian IFR fleet was very likely converted over to ADS-B already before it was issued. At the current time, it is still lawful to fit a mode-C transponder to aircraft which will never fly in class E or class C (e.g., aircraft that spend their whole lives in class G with the odd occasional foray into class D airports). I believe it’s foolish to fit new mode-C installations even in that case, though: Mode-S transponders with built-in digital altitude encoders which sip hardly any power are cheap, and mode-C transponders are getting harder and harder to find. You’re only allowed to make ADS-B broadcasts with your mode-S transponder if you have a GNSS position source which meets the applicable TSOs. That adds considerably to the price of ADS-B unless you already have something like a Garmin GNS430W (unlikely in a glider) or if you’ve found a cheap transponder with a TSO GNSS hockey-puck built in (Garmin does one, but it isn’t attractively cheap IMHO) So, to summarize: 1. For all intents and purposes, mode C probably won’t be fitted to aircraft anymore. 2. As existing mode-C devices in VFR aircraft develop faults, it’ll be cheaper to replace them with mode-S than to repair them. 3. Even when a considerable amount of VFR aircraft are converted to mode-S, most of them still won’t be broadcasting ADS-B. 4. Almost all IFR-capable aircraft will already be broadcasting ADS-B as of the beginning of this month. I went through all this late last year: Had a Trig TT21 installed in the RV-6 last month, connected up to the Garmin GNS430W navigator that I already owned, broadcasting ADS-B. I’m now so visible that I feel like I’m naked when I’m flying :-) Cheers, - mark
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