{"id":"F2008L02977","name":"AD/PA-23/12 Amdt 2 - Empennage - Inspection","slug":"ad-pa-23-12-amdt-2-empennage-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74957,"registerId":"commonwealth-F2008L02977-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Piper PA-23 (Apache and Aztec) Series Ae","sectionType":"division","heading":"Piper PA-23 (Apache and Aztec) Series Aeroplanes","content":"### Piper PA-23 (Apache and Aztec) Series Aeroplanes\n\n| AD/PA-23/12 Amdt 2 | Empennage - Inspection | 9/2008 |\n| ------------------ | ---------------------- | ------ |\n\n```html\n

Applicability:

Models PA-23 and PA-23-160 with S/Nos. 23-1 to 23-1267.

Requirement:

1. Remove the tail cone, covers and fairings, and visually inspect for cracks in the castings listed below.

Part

Casting Part No.

Forging Part No.

Elevator Torque Tube Bracket

17033-00 & 17033-01

19407-00

Front Stabiliser Attachment

17049-00 & 19253-00

19409-02

Rudder Torque Tube Horn

17060-00

19405-00

Elevator Torque Tube Horn

17066-00

19404-00

Rudder Torque Tube Bracket

17062-00

19408-00

Fin Attachment Bracket

17072-00

19406-00 or 19406-02

Note: All the forged parts listed have integral raised digit forging numbers. Therefore, absence of raised digits will serve to identify the part as a casting.

2. Remove from the aircraft all castings listed in Para. 1, clean thoroughly removing all paint, and inspect for cracks using an approved fluorescent or dye penetrant method. Prior to reinstallation of airworthy castings, clean thoroughly, and apply zinc chromate primer.

Inspect and re-assemble in accordance with Piper SB No. 155B. Replace cracked castings with a replacement forged or cast part.

Note 1: When any casting is replaced by its respective forging listed above, the repetitive inspections of Paras. 1 and 2 are no longer required for that part.

Note 2: FAA AD 63-26-03 refers.

Compliance:

For Para. 1 - At each scheduled inspection for issue of a maintenance release.

\n```\n\n| | For Para. 2 - For castings with more than 1000 hours time in service, at the first scheduled inspection for issue of a maintenance release after achieving 1000 hours time in service, and thereafter at intervals not exceeding 500 hours time in service. |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Amendment becomes effective on 28 August 2008. |\n| Background: | The original issue of this AD specified 100 hourly inspection of the empennage in accordance with Piper SB Nos. 146B and 155B, and FAA AD 57-13-9.DCA/23/12A introduced a requirement for fluorescent or dye penetrant inspection at 500 hour intervals; divided the AD into a Compliance statement and a Requirement statement in a separate supplement; and deleted mention of SB No. 146B.AD/PA-23/12 Amdt 1 changed the title; and amalgamated the Requirement statement and Compliance statement.AD/PA-23/12 Amdt 2 clarified the serial number applicability and Compliance statement; identified FAA AD 63-26-03; and removed the inspections specified in SB No. 146B for transfer to AD/PA-23/91 “Elevator Butt Rib and Plate - Inspection”. |\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n18 July 2008","sortOrder":0},{"sectionNumber":"AD/PA-23/12 Amdt 2","sectionType":"part","heading":"AD/PA-23/12 Amdt 2","content":"## AD/PA-23/12 Amdt 2","sortOrder":1},{"sectionNumber":"Empennage - Inspection","sectionType":"part","heading":"Empennage - Inspection","content":"## Empennage - Inspection","sortOrder":2},{"sectionNumber":"9/2008","sectionType":"part","heading":"9/2008","content":"## 9/2008","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"This amendment clarifies serial‑number applicability and the compliance statement, explicitly references FAA AD 63‑26‑03, and removes certain inspections previously specified in SB No.146B (transferred to AD/PA‑23/91). It also establishes that replacing a listed casting with its forging ends the repetitive inspection requirement for that part (Note 1), thereby altering which aircraft/parts remain subject to ongoing inspections."},"complexity_factors":["Applicability limited to specific serial numbers (S/N 23-1 to 23-1267) requires accurate aircraft identification.","Multiple listed parts with distinct casting and forging part numbers — identification of casting vs forging relies on presence/absence of raised digit forging numbers.","Two inspection regimes: Para. 1 (at each scheduled maintenance‑release inspection) and Para. 2 (for castings >1000 hours: first inspection after 1000 hours then every 500 hours) — requires tracking component hours and maintenance schedules.","Inspection method requirements: removal of tailcone, covers and fairings, plus fluorescent or dye‑penetrant inspection (more resource‑intensive than visual inspection).","Procedural requirements for cleaning, application of zinc chromate primer, and reassembly per Piper SB No.155B add shop labour and materials steps.","Replacing castings with forgings changes long‑term compliance (Note 1) — creates a trade‑off between replacement cost and reduced recurring inspections.","Cross‑references to external documents (Piper SB No.155B and FAA AD 63‑26‑03) introduce reliance on other materials for full compliance.","Compliance timing tied to issuance of a maintenance release rather than a simple flight‑hour clock increases administrative coordination between operators and maintainers."],"plain_english_summary":"This amendment requires owners/operators of Piper PA‑23 and PA‑23‑160 (S/N 23‑1 to 23‑1267) to remove the tailcone coverings and inspect specified empennage castings for cracks by visual and fluorescent or dye‑penetrant methods, clean and prime reinstalled parts, and replace cracked castings (replacement by a forging removes the repetitive‑inspection requirement). Aircraft owners/operators and maintenance providers fund and carry out the work, and must track maintenance‑release inspections and component hours to meet the stated inspection intervals (Paras. 1–2)."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Amendment 2 represents incremental refinement rather than scope expansion. The original AD addressed empennage inspections; Amendment 2 merely clarifies serial number applicability, streamlines compliance language, and transfers one inspection requirement (SB 146B) to a separate AD. The core safety purpose — preventing tail section failures through inspection of specific castings — remains unchanged from the original 1957-era safety concern."},"complexity_factors":["Single technical subject matter (empennage castings) with narrow applicability","Clear two-tier inspection structure (visual vs. penetrant testing)","Specific part numbers and serial number ranges provided in table format","Two simple compliance pathways: repetitive inspections OR one-time replacement with forged parts","Limited cross-references (only to Piper Service Bulletin 155B and FAA AD 63-26-03)","No nested exceptions or conditional logic beyond the replacement exemption","Straightforward effective date and amendment history"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of Piper PA-23 and PA-23-160 aircraft (serials 23‑1 to 23‑1267) to inspect six critical empennage castings for cracks. Visual checks at scheduled maintenance and more rigorous fluorescent/dye‑penetrant inspections (initial at 1,000 hours TIS, then every 500 hours) are required; cracked castings must be replaced and primed. Upgrading to stronger forged parts removes the repetitive inspection requirement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-23-12-amdt-2-empennage-inspection","history":"/api/acts/ad-pa-23-12-amdt-2-empennage-inspection/history","analysis":"/api/acts/ad-pa-23-12-amdt-2-empennage-inspection/analysis","conflicts":"/api/acts/ad-pa-23-12-amdt-2-empennage-inspection/conflicts","importantCases":"/api/acts/ad-pa-23-12-amdt-2-empennage-inspection/important-cases","documents":"/api/acts/ad-pa-23-12-amdt-2-empennage-inspection/documents"}}