Airservices Australia is in the process of completing a review report into the effectiveness of Class D airspace at the six former GAAP airports.
The review comes as the five-year anniversary approaches of Class D being implemented at Archefield, Bankstown, Camden, Jandakot, Moorabbin and Parafield Airports, replacing the old General Aviation Approach Procedures (GAAP).
In response to a question from Australian Flying, an Airservices spokesperson said "Airservices has recently conducted a review of the safety of Metropolitan Class D control towers which included an examination of the effectiveness of the change from GAAP to Metro D procedures in June 2010.
"While this review is still being finalised, the research indicates that there has been an overall improvement in safety at these aerodromes."
No indication has been given of when the review is expected to be finished, or if it will be released to the public.
The idea of Class D to replace GAAP initially fractured the industry with some believing no change was needed, some supporting the move to Class D and other thinking Class D would actually make the airports unsafe.
Sydney Flying Club Vice President Mike Allsop says the club has found Class D at Bankstown has not been as onerous as many predicted.
"Despite the doom and gloom from some commentators, we have found US Class D a relatively painless alternative to GAAP.
"National consistency of Class D procedure is a plus. The standard tracks at Bankstown are still published and are expected to be used due to flow control requirements. The zone is too small and constrained to permit just pitching up anywhere unannounced.
"Taxi calls are no great imposition, and now with visible markings for taxiways (essential with the new lettering introduced by BAL), these make sense.
"The ceiling issue for VFR can usually be overcome on days when it makes sense by using the 'Special VFR due cloud' provision. Again this is a bit of a procedural imposition, but the tower are very helpful and understanding despite not being able to offer that option unless requested.
"The only black mark for training operations is the limitation on VFR circuits if an aircraft is inbound on an instrument approach (even visual). The code 3000 requirement is a constant source of VFR pilot forgetfulness – either not changing from 1200 inbound or not changing to 1200 outbound at the zone boundary. Pilots are bemused at it – there being no obvious benefit to anyone through having to change codes when not under radar surveillance and at a busy time in the flight profile."
The arguments for and against the change were outlined in the Australian Flying newsfeed in April 2010.