HMAS Stirling
Australia's entire submarine fleet is headquartered at Garden Island (suburban Perth).
I presume that there is some SAR capability operating out of there.
Probably about four or five days away from current target site - presuming something is available to be mobilised.
Double that distance if you look at Diego Garcia and US or British assets.
For this aircraft to have flown to the current target area it would have travelled about 7,000 km.
Is that possible? Even with a generous allowance for sea drift, is that possible?