A to B direct, IFR using TSO C-129 GPS-RNAV

[ForkTailedDrKiller]

I would like to hear from others more knowledgeable than I, on the "legality" or otherwise of the following senario.

Say I wish to fly Townsville to Toowoomba, on an IFR plan, and my aeroplane has standard navaids plus the Garmin 430 which is TSO C-129.

Am I required to follow a published route and track via VOR/NDB navaids where possible - eg TL-CHARD-MRB-BTR-TAM-OK-TWB, or can I just plan YBTL - YTWB direct?

I fly this route regularly, and provided I stay high (which I do eg A090) I will remain on SSR for most, if not all, of the trip. SSR sometimes drops out for a bit around Emerald and passing abeam Gayndah.

If I plan YBTL-YTWB direct, Townsville Clearance Delivery will amend it to "via Chard" because I think that gives them a convenient que to hand me off to Brisbane Centre. However, ATC do not seem to have a problem with "direct".

I first twigged to this, beacuse coming back the otherway, I have been offered "Toowoomba direct Townsville" by ATC. Always seems kind of wierd when they say "you're indentified 570 nm SSE of Townsville, confirm level passing".

My reading of the regs is that you need to have a TSO C-145 GPS to track direct, solely by reference to the GPS. I believe that an upgrade to TSO C-145 is available for the Garmin 430, at reasonably low cost.

Its not a big deal for me because if the GPS cr*ps itself, I know where I am and can easily pickup the airway, but I am curious about how kosher it is to just go Townsville to Toowoomba (for example) direct - on a TSO C-129 GPS.

Dr :8

PS: I have also noticed that coming into TL from the west, ATC seem quite happy to clear me from the middle of nowhere direct TL, which wasn't the case previously.

[NZScion]

I can't speak for aus, but in NZ it is perfectly legal to fly on a GPS primary means system away from published airways, as long as you are above FL150 (IIRC). The downside is that if you are in controlled airspace and there is conflicting traffic, the traffic on the airway will get priority.

[Horatio Leafblower]

Been doing a little reading on this myself lately and your understanding is correct :ok:

I think the difference is the C145/6 standard can filter out a dodgy signal and continue to provide guidance, whereas the C129 will sit there looking back at you if it has a problem.

Certainly CASA's guidance/training material exhorts pilots to plan via terrestrial aids if using C129.

What ATC is up to I dunno, but in my experience those guys have a much better grip on the AIPs etc than any pilot ever will :ouch:

[Private Partz]

FTDK

Plan via Naviads and published routes and submit (NAIPS?) because the person who receives the plan is unlikely to be the ATCO who you will first talk to on frequency.

When airborne and in contact request "DIRECT XXX" and see what happens. In Radar airspace i.e. Eastern seaboard, you're more than likely to get it.