The news link is wrong, the Australian Army hasn't operated the Chinook since 1973. But that is hardly surprising, as the source is the ABC.
The RAAF originally acquired the CH-47C in 1973. One was lost (with an RAF exchange pilot), and the remaining 11 were sold back to the US, in the late '80s I think.
Then Army decided they needed to refuel the S-70A Blackhawks, and Chinook would be a good cab for the job. So 4 of the old C models were upgraded to CH-47D and delivered to Army in the mid '90s. Guess what? 4 were not enough - so a further 2 (newbuild) CH-47Ds were acquired, around about 2000. One of the earlier aircraft was lost this year in Afstan, and that has been replaced from the 5 AVN Regt fleet in Townsville.
I believe 2 are deployed now in Afghanistan (of which 1 must be U/S), 1 in PNG (prob U/S), and 1 in Horn Island (prob U/S transitting to/fro PNG). That leaves the remaining 1 in deep maintenance in TVL.
7 x CH-47F are on order for delivery in 2014. The moral of this story - you can't run an effective operational fleet with 5 airframes !! But I'm sure you knew that.
