Murrayfield Airport south of Perth has lost its instrument approach after operator Royal Aero Club of WA (RACWA) asked for the airport to be de-certified.
New rules that were implemented in May this year mean that airports must be certified to have RNAVs.
According to a statement on the CASA website, RACWA successfully transitioned Murrayfield to the new regulations, but has since reversed its decision and requested de-certification.
CASA de-certified the airport from Thursday, 27 October, with formal notification via NOTAM.
The introduction of CASR Part 139 put 350 airports in the position of needing to transition to the new rules, of which all but six complied initially.
Mallacoota in Victoria has since recovered its certification and RNAV.
Comment has been sought from RACWA.