K-Ex / High 6,
I don't think the F100's are being phased out. The pair of much publicised Q400's due in March are more likely seen as a means of filling the gaps that the F100's can't get into.
As for GNSS, I believe an in country survey is currently being undertaken on behalf of PX, but actual implementation is still seen as two or three years down the track.
The other rumour circulating at this time is that Boeing are offering a new leased 767 on favourable terms as a stopgap due to the 787 delivery now being pushed back to 2014.