Soon after your departure report from Birdsville, Centre will advise you that you'll lose VHF comms at time zz, and won't regain them until Steel (reporting point). Simply downgrade to VFR (yes, obviously you'll have to change to a VFR altitude) nominate a sartime for steel, and then re-establish IFR at steel.
Dead simple.
BTW If you've got an ELT, no HF required. If you're doing a fair bit of outback work, you should consider hiring a satphone for Pilot Briefing and SARTIME contact. I hired one recently when the Chieftain's HF antenna downgraded itself to a clothesline. PM me if you want the details of a good satphone hire company I've recently used.
I reckon you're pretty brave donning the old oxygen mask. It's outside of my acceptible risk area!
Last edited by Rojer Wilco; 10th Jun 2009 at 02:08.