Beechcraft circling YSSY Sun morning

[Mornings minion]

Noticed Beech B300 B350 ADA3 reg VH-FIY circling YSSY for some time this morning. As still a newbie unable to post pic from Flight Radar.
Anyone know what's going on here?

[BigPapi]

Probably AirServices nav aid calibration/testing?

[Global Aviator]

Have they got more than 1? Thought that was VH-FIX.

[megle2]

Pretty sure they have 3 FIX FIY FIZ
FIX is a early model upgraded to Proline 21
The other 2 are 2011 models

[Power]

ILS calibration this morning