{"id":"F2008L02980","name":"AD/PA-23/91 - Elevator Butt Rib and Plate - Inspection","slug":"ad-pa-23-91-elevator-butt-rib-and-plate-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74963,"registerId":"commonwealth-F2008L02980-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-23/91 | Elevator Butt Rib and Plate - Inspection | 9/2008 |\n| ----------- | ---------------------------------------- | ------ |\n\n| Applicability: | Model PA-23 with serial numbers 23-1 to 23-1284, and 23-1286.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | If elevator assembly P/No. 17058-00 is installed - visually inspect for cracks in elevator butt rib P/No. 17058-3 and elevator butt rib plate P/No. 17058-20. Replace cracked parts before further flight. Parts must be assembled and installed to obtain proper alignment, and to prevent distortion and over-torquing of the attachment bolts. Piper Service Bulletin No. 146B refers.If elevator assembly P/No. 19446 is installed - no further action is required by this AD.Note 1: This inspection was previously included in AD/PA-23/12 Amdt 1.Note 2: FAA AD 63-12-02 refers. |\n| Compliance:    | Aircraft which have previously been inspected in accordance with AD/PA-23/12 Amdt 1 - at each scheduled inspection for issue of a maintenance release.Aircraft which have not previously been inspected in accordance with AD/PA-23/12 Amdt 1 - within 100 hours time in service following the effectivity date of this AD and thereafter at each scheduled inspection for issue of a maintenance release.                                                                                                                                                                              |\n|                | This Airworthiness Directive becomes effective on 28 August 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| Background:    | When AD/PA-23/12 Amdt 1 was reviewed it was decided to remove the inspection specified in FAA AD 63-12-02 (Piper SB No. 146B) and use it to create a new AD. The serial number applicabilities of FAA ADs 63-12-02 and 63-26-03 are different and warrant separate ADs.                                                                                                                                                                                                                                                                                                                 |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n18 July 2008","sortOrder":0},{"sectionNumber":"AD/PA-23/91","sectionType":"part","heading":"AD/PA-23/91","content":"## AD/PA-23/91","sortOrder":1},{"sectionNumber":"Elevator Butt Rib and Plate - Inspection","sectionType":"part","heading":"Elevator Butt Rib and Plate - Inspection","content":"## Elevator Butt Rib and Plate - Inspection","sortOrder":2},{"sectionNumber":"9/2008","sectionType":"part","heading":"9/2008","content":"## 9/2008","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope. It was deliberately separated from a previous bundled AD (AD/PA-23/12 Amdt 1) specifically to address the distinct serial number applicability of FAA AD 63-12-02. The scope remains tightly focused on elevator butt rib inspection for specific Piper PA-23 aircraft and has not expanded beyond this original safety purpose."},"complexity_factors":["Short, single-purpose directive with one primary requirement (visual inspection)","Only 2 conditional branches (which elevator assembly part number is installed)","Limited applicability (specific serial number range, specific part number)","Simple compliance structure with two pathways based on prior inspection history","Minimal cross-referencing (only references one previous AD, one FAA AD, and one Service Bulletin)","No nested exceptions or complex defined terms"],"plain_english_summary":"This AD mandates inspection of the elevator butt rib and butt rib plate for cracks on Piper PA-23 Apache/Aztec aircraft (S/N 23-1 to 23-1284, and 23-1286) only if fitted with elevator assembly P/N 17058-00; aircraft with P/N 19446 are unaffected. Cracked parts must be replaced before flight.\n\nIf already inspected, continue inspections at every scheduled maintenance release; if not, inspect within 100 flight hours after 28 Aug 2008 then at every scheduled maintenance release. It prevents structural failure and loss of control."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The inspection was removed from AD/PA‑23/12 Amdt 1 and placed in this separate AD because the FAA AD serial-number applicabilities differed. The new AD narrowly applies to PA‑23 serials 23‑1 to 23‑1284 and 23‑1286 and only when elevator assembly P/No. 17058‑00 is installed; aircraft with assembly P/No. 19446 are excluded."},"complexity_factors":["Applicability limited by serial-number range (PA‑23 serials 23‑1 to 23‑1284, and 23‑1286), increasing tracking and record-checking burden.","Requirement is conditional on installed elevator assembly part number (P/No. 17058‑00 triggers inspection; P/No. 19446 requires no action).","Two-tier compliance timing: different intervals apply depending on whether the aircraft was previously inspected under AD/PA‑23/12 Amdt 1 (at each scheduled maintenance vs. within 100 hours then recurring).","Mandatory corrective action: replace any cracked parts before further flight, which creates potential immediate parts-cost and downtime obligations for operators.","Assembly and installation must achieve proper alignment and avoid distortion/over‑torquing of attachment bolts, creating a workmanship/compliance requirement tied to Piper SB No.146B.","Cross-references to prior AD (AD/PA‑23/12 Amdt 1) and FAA ADs increase administrative complexity and reliance on external documents for full compliance."],"plain_english_summary":"This AD requires operators of specified Piper PA‑23 aeroplanes to visually inspect the elevator butt rib and butt rib plate when elevator assembly P/No. 17058‑00 is fitted, and to replace any cracked parts before further flight. No action is required if assembly P/No. 19446 is fitted.\n\nIf the aircraft was inspected under AD/PA‑23/12 it must be inspected at each scheduled maintenance; otherwise inspection is required within 100 hours and thereafter at scheduled maintenance. Owners/operators bear inspection and replacement costs; maintenance staff must assemble parts correctly per Piper Service Bulletin No.146B."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-23-91-elevator-butt-rib-and-plate-inspection","history":"/api/acts/ad-pa-23-91-elevator-butt-rib-and-plate-inspection/history","analysis":"/api/acts/ad-pa-23-91-elevator-butt-rib-and-plate-inspection/analysis","conflicts":"/api/acts/ad-pa-23-91-elevator-butt-rib-and-plate-inspection/conflicts","importantCases":"/api/acts/ad-pa-23-91-elevator-butt-rib-and-plate-inspection/important-cases","documents":"/api/acts/ad-pa-23-91-elevator-butt-rib-and-plate-inspection/documents"}}