AD/PA-23/87 - Engine Air Filter

Overview

The Civil Aviation Regulations 1998, specifically under PART 39 - 105, include a schedule of airworthiness directives designed to maintain the safety standards of aircraft operations in Australia. One such directive, AD/PA-23/87, addresses the specific issue of engine air filters on Piper PA-23 (Apache and Aztec) series aeroplanes manufactured with certain filters between January 1997 and September 1998. The problem this directive was introduced to resolve was the cracking and break-up of certain air filter elements due to manufacturing errors, which posed a risk of pieces being ingested by the engine. The directive was enacted by the Civil Aviation Safety Authority to ensure compliance with safety standards and to prevent potential engine failure by requiring inspections of these specific filters. The objective is to ensure that pilots and aircraft owners take necessary precautions to avoid the risks associated with these defective filters.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to Piper PA-23 (Apache and Aztec) series aeroplanes with certain engine air filter components manufactured between January 1997 and September 1998. The directive applies to aircraft with serial numbers 27-505 through 27-622 for PA-23-235 and 27-01 through 27-2504 for PA-23-250 models, all of which are fitted with a Facet engine air inlet filter part number 638873. The directive mandates inspections of these specific air filters to prevent pieces from being ingested into the engine, as detailed in Piper Service Bulletin No. 1022 and Purolator Service Bulletin No. 090298.01. Notably, under Civil Aviation Regulation 42ZC (4) (d), pilots holding a valid licence, excluding student pilots, are permitted to change the air filters themselves. The directive became effective on 9 September 1999, and for installed filters, compliance requires inspection at the next engine air inlet filter element inspection or within 25 hours of service from the directive's effective date, whichever is sooner, and subsequently at intervals not exceeding 25 hours in service. Spare filters must also be inspected before installation.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105 under the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives, contain a directive pertinent to Piper PA-23 (Apache and Aztec) series aeroplanes (section 1). This directive, known as AD/PA-23/87, concerns engine air filters that may have been manufactured with specific defects (section 2). The directive applies to certain serial numbers of PA-23-235 and PA-23-250 aircraft, specifically those fitted with a Facet engine air inlet filter part number 638873 manufactured between January 1997 and September 1998 (section 3). To ensure airworthiness, these filters must be inspected to prevent pieces from being ingested by the engine, thereby avoiding potential engine failure or damage (section 4). The obligations imposed by this directive primarily concern aircraft owners, operators, and maintenance personnel (section 5). Specifically, installed filters must be inspected at the next engine air inlet filter element inspection or within 25 hours of the directive's effective date, whichever comes first, and subsequently at intervals not exceeding 25 hours of service time (section 6). Additionally, any spare filters must be inspected before being installed in an engine (section 7). Compliance with this directive is crucial, as failure to adhere to the inspection requirements may result in the in-service removal of affected filters, rendering the directive inapplicable (section 8). In the event of non-compliance with the specified requirements, there are potential consequences (section 9). Although the regulations do not explicitly state civil or criminal penalties, the failure to maintain airworthiness standards can lead to severe consequences, including the potential for engine ingestion of filter pieces, which could result in engine failure, damage to the aircraft, or even accidents (section 10). Additionally, regulatory authorities may take action against the non-compliant parties, leading to further penalties or enforcement actions (section 11). The directive explicitly references FAA Airworthiness Directive 99-05-09, indicating a collaborative approach to safety across jurisdictions (section 12).