A proposed airworthiness directive that would require propellers to be overhauled every six years has prompted a backlash from the general aviation industry.
CASA issued Proposed Airworthiness Directive (PAD) PAD/Prop/1 Amdt 3 in April, calling for industry submissions by this Monday, 15 June.
According to CASA, the new measures are necessary because "information received through the CASA Service Difficulty Reporting [SDR] system and other reports indicating that propellers that are presented for repair/overhaul at extended calendar times commonly exhibit defects that compromise the flight safety of aircraft.
"The most common defects relate to excessive corrosion to the hub and blade areas and significant wear of the components of controllable propellers due to seal degradation and subsequent oil loss."
Initially, the PAD applied to all propellers, but CASA is believed to have recently exempted fixed-pitch props and props fitted to home-built aeroplanes.
Some industry commentators believe that the PAD should apply to no props at all.
Aeroplane owner and former president of the Aircraft Owners and Pilots Association (AOPA) Australia, Andrew Andersen, says that the proposed six-year overhaul period is not supported by the evidence CASA cites in the PAD.
"CASA has completely failed to make a case for this proposed change to an existing AD," he said. "It claims that its proposal is supported by SDR data, but this not so. It has changed the applicability of the AD and introduced new, arbitrary, CASA-invented requirements, without justification.
"CASA has not properly described the impact of the proposed legislation. It does not include an estimate of the number of affected aircraft, or the estimated cost of its proposals. CASA is imposing further cost on GA without disclosing the economic impact of its proposals.
"It is noteworthy that all FAA proposed airworthiness directives include an estimate of the number of affected aircraft and the cost. CASA rarely does, and then only when required to do so by another government agency. It is very hard to reconcile the government’s response to the ASRR [Forsyth Report] with such arrogant behaviour."
According to Andersen, of the 253 SDRs that apply, only 13 were reported as corroded and 12 as leaking oil.
The president of another industry body, who preferred not to be identified, supports Andersen's position.
"Again the airworthiness folks in CASA appear to be again breaking new regulatory ground in how they implement these initiatives," he said. "The amendment to the prop AD is being done by creating a PAD – Proposed Airworthiness Directive. I thought that ADs (other than emergency ones) had to proceed through a rule making process (NPRM, etc) that allows for the proposal to be amended as a result of comments received.
"This proposed AD says that internal (i.e. within CASA) consultation took place in September 2014 and that external consultation closes on 15 June 2015 and that owners will have to comply within two years of the effective date of this PAD. If this is how the new CASA consults then I don’t see much difference from the old one.
"Like the 'ruling' that the CASA airworthiness folks used to implement Cessna SIDS, theproposed AD is simply a means of bypassing the proper consultation mechanisms."
Other submissions to the PAD are believed to be concerned that the lack of reasoning and process behind the conclusions are inconsistent with promises from CASA DAS Mark Skidmore that new regulations must take into account the impact on the industry and show a clear improvement in safety.
PAD/Prop/1 Amdt 3 can downloaded from the CASA website.