Vag277 said "the RA-Aus membership is their condition to grant a certificate to fly the aircraft in accordance with the CAO 95 series exemptions and they came about as a result of a parliamentary inquiry into the fatal accident rates in early ultra-light aircraft."
It is apopular misconception that the CAO's requirRA-Aus and their ilk. This is not the case. CASR Part 200 exempts CAO 95.10, 95.32, 95.55 aircraft and others from the CASR's which includes Part 47 which deals with registration of aircraft so these aircraft are by definition "unregistered aircraft" . CASR 200.25 completes the circle:
CIVIL AVIATION SAFETY REGULATIONS 1998 - REG 200.025
Flying unregistered aircraft For paragraph 20AB(1)(a) of the Act, a person is taken to hold a civil aviation authorisation that is in force and authorises the person to perform a duty that is essential to the operation of an unregistered Australian aircraft during flight time if:
(a) the person holds a pilot certificate granted by a sport aviation body that administers aviation activities in the aircraft; and
(b) the person operates the aircraft in accordance with the sport aviation body's operations manual.
As you can see there is no requirement either by the CAO or the CAR's or the CASR's for membership of RA-Aus. For example CAO95.55 says:
6.1(d) subject to the other conditions set out in this Order, the aeroplane must be operated in accordance with the requirements of the RAA Operations Manual;
It is the RA_Aus Operations Manual (approved by CASA) that dictates that membership is a requirement. How CASA can approve a manual with such a requirement when none exists at law is beyond me.