I have it on good authority (although I couldn't quote the reg's) that a sat phone will do in lieu of an HF
How so? My understanding is that it is a requirement to be in continuous communication with ATC if you are on an IFR plan. I generally can get around this by downgrading to VFR when I believe that I will not be able to maintain VHF comms. I carry a sat phone just in case I need to talk to someone but I can't see how it meets the requirements for IFR.
VFR - not a problem!
I have not found not having HF to be a problem for private ops all over Oz - including transcontinental from the east coast to Broome and Perth, but I have not had to go IFR in a really remote area (came close to it though between Ayers Rock and Leonora last year - didn't we Jaba !!!)
I see that ICOM have a new fangle radio that covers the spectrum of HF/VHF/UHF. Not TSO'd but would get the job done.
Dr 