COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Piper PA-23 (Apache and Aztec) Series Aeroplanes
AD/PA-23/87 Engine Air Filter 9/99
PA-23-235 aircraft serial numbers 27-505 through 27-622, and PA-23-250 aircraft serial numbers 27-01 through 27-2504;
fitted with a Facet engine air inlet filter part number (P/N) 638873 manufactured in the period January 1997 to September 1998.
Filters of concern can be identified by accessing the filter and locating the brand name and part number. Filters of concern are branded “FACET 638873” in 0.250”(1/4”) high white characters with no date code.
To prevent pieces of a damaged air filter from being ingested in the engine, inspect applicable air filters in accordance with Piper Service Bulletin Number (No.) 1022 and/or Purolator Service Bulletin No. 090298.01.
Civil Aviation Regulation (CAR) 42ZC (4) (d) permits the holder of a pilot licence, other than a student pilot, that is valid for the aircraft, to change the air filter. Therefore, should applicable air filters be removed from service prior to the effective date of this directive, the directive will no longer be applicable.
FAA Airworthiness Directive 99-05-09 refers.
Installed filters: At next inspection of the engine air inlet filter element or within 25 hours time in service from the effective date of this directive, whichever occurs first, and thereafter at intervals not to exceed 25 hours time in service.
Spare filters: Prior to installation in a engine.
This Airworthiness Directive becomes effective on 9 September 1999.
This directive has been issued to address reports of cracking and break up of certain air filter elements. The defects resulted from evidence of manufacturing errors in filters produced during the period January 1997 though September 1998. The directive requires applicable filters to be inspected for evidence of deterioration.