With "Great Trepidation" (this IS a tune-up... right???, NO???)-
Aircraft Descriptions on Air Operator's Certificates:
For Non Transport Category Helicopters and Fixed Wing Multi Engine and/or Turbine Powered Aircraft 5700kg MTOW in charter and aerial work operations....
CASA is 'your' friend (apparently), link to start with here and go hard/good luck/be safe:
https://www.casa.gov.au/standard-pag...s-certificates
Rgds all
S28- BE