{"id":"F2007L00747","name":"AD/PA-25/42 - Horizontal Stabiliser Forward and Aft Supports","slug":"ad-pa-25-42-horizontal-stabiliser-forward-and-aft-supports","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":64426,"registerId":"commonwealth-F2007L00747-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Piper PA-25 (Pawnee) Series Aeroplanes","sectionType":"division","heading":"Piper PA-25 (Pawnee) Series Aeroplanes","content":"### Piper PA-25 (Pawnee) Series Aeroplanes\n\n| AD/PA-25/42 | Horizontal Stabiliser Forward and Aft Supports | 4/2007 |\n| ----------- | ---------------------------------------------- | ------ |\n\n| Applicability: | All Model Piper PA-25, PA-25-235, and PA-25-260 series aircraft;All Model CHINCUL “Pawnee” PA-25, PA-25-235, and PA-25-260 aircraft;All Model LAVIA “Puelche” PA-25-235 and PA-25-260 aircraft;that have accumulated 1,500 or more flight hours;except aircraft with serial number LA-260-06008 and subsequent.                                                                                                                                                                                                            |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Perform the requirements of paragraph “Actions”, sub-paragraph “Initial” of LAVIASA Service Bulletin (SB) No. 25/53/03 Revision 0.2. If any evidence of cracks, corrosion or other discrepancy is detected, action in accordance with sub-paragraph “Definitive” of SB No. 25/53/03 Revision 0.Note 1: LAVIASA Service Bulletin No. 25/53/03 Revision 0 may be obtained by emailing laviasa@speedy.com.ar or airworthiness.directives@casa.gov.auNote 2: Argentina D.N.A. AD RA 2006-06-01 Rev.1 Amdt 39/03-041 refers. |\n| Compliance:    | 1. Within 50 flight hours after 12 April 2007, unless already accomplished. Inspect thereafter at intervals not to exceed 100 flight hours or the annual inspection, whichever occurs first; until Requirement 2 is accomplished.2. Before further flight.                                                                                                                                                                                                                                                                 |\n|                | This Airworthiness Directive becomes effective on 12 April 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| Background:    | Reports were received of severe corrosion and cracks of both supports of the horizontal stabilisers on several affected aircraft. This Directive requires initial and repetitive inspections and further actions if discrepancies are detected.                                                                                                                                                                                                                                                                            |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n26 February 2007","sortOrder":0},{"sectionNumber":"AD/PA-25/42","sectionType":"part","heading":"AD/PA-25/42","content":"## AD/PA-25/42","sortOrder":1},{"sectionNumber":"Horizontal Stabiliser Forward and Aft Su","sectionType":"part","heading":"Horizontal Stabiliser Forward and Aft Supports","content":"## Horizontal Stabiliser Forward and Aft Supports","sortOrder":2},{"sectionNumber":"4/2007","sectionType":"part","heading":"4/2007","content":"## 4/2007","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with focused, original intent: addressing a specific airworthiness concern (corrosion/cracking in horizontal stabiliser supports) on a defined aircraft population. The scope remains tightly constrained to the safety issue identified in the background."},"complexity_factors":["Single, clearly defined applicability clause with specific model numbers and flight hour threshold","Straightforward two-stage compliance structure (initial + repetitive)","Only one primary technical reference (LAVIASA Service Bulletin 25/53/03)","Simple conditional logic: 'if discrepancy found, do definitive action'","No nested definitions or extensive cross-referencing to other legislation","Short document (approximately 250 words of substantive content)","Single exception clause (serial number cutoff)"],"plain_english_summary":"Owners/operators of older Piper PA‑25 \"Pawnee\" and equivalent Argentine‑built agricultural aircraft must carry out mandatory inspections of the horizontal stabiliser supports after reports of cracking and corrosion on high‑time airframes.  \n\nThe AD requires prompt inspection and corrective action (repair or replacement before further flight) to prevent loss of pitch control and catastrophic failure in heavily used agricultural aircraft."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD stays within the original safety‑remedial purpose: identify and repair corrosion/cracking of horizontal stabiliser supports on older PA‑25 series aircraft. It does not extend obligations beyond inspection and repair of the identified structural components, nor does it add unrelated regulatory conditions. The instrument delegates technical execution to a manufacturer/service organisation bulletin but does not broaden the class of affected parts or introduce ongoing regulatory duties beyond the repeat inspections until definitive repair."},"complexity_factors":["Multiple model variants and three separate manufacturer names listed in Applicability (Piper, CHINCUL, LAVIA).","Flight‑hour threshold applicability (1,500 flight hours) combined with a serial‑number exception (serials LA‑260‑06008 and subsequent excluded).","Delegation of technical details to an external LAVIASA Service Bulletin rather than including full instructions in the AD (dependency on external document).","Two‑stage action structure in the SB referenced: an ‘Initial’ inspection and a ‘Definitive’ corrective action, with differing compliance timings.","Conditional compliance timing: initial inspection within 50 flight hours after the AD effective date, then repetitive inspections every 100 flight hours or at annual inspection (whichever first) until definitive action completed; definitive action must be done before further flight.","Cross‑reference to a foreign airworthiness directive (Argentina D.N.A. AD RA 2006‑06‑01 Rev.1 Amdt 39/03‑041) and contact details for obtaining the SB add layers to compliance logistics.","Minor textual ambiguity in numbering/label‑referencing (the AD text refers to ‘Requirement 2’ in Compliance while the Requirement section presents sub‑paragraphs as other labels), requiring careful reading to determine which actions relate to which timelines."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This Airworthiness Directive (AD) orders inspections and, if needed, repairs to the forward and aft supports of the horizontal stabiliser on selected Piper PA‑25 “Pawnee” series aeroplanes. (See: Applicability; Requirement; Compliance.)\n\n**Who it affects**\n\n- Owners/operators of all Model Piper PA‑25, PA‑25‑235 and PA‑25‑260 series aeroplanes and the equivalent CHINCUL “Pawnee” and LAVIA “Puelche” models, but only those aircraft that have accumulated 1,500 or more flight hours. Aircraft with serial number LA‑260‑06008 and later are excluded. (Applicability.)\n\n**What you must do**\n\n- Perform the initial inspection called for in LAVIASA Service Bulletin No. 25/53/03 Revision 0.2. If you find any cracks, corrosion or other discrepancies, carry out the corrective (\"Definitive\") actions described in the Service Bulletin before further flight. (Requirement.)\n\n- Timing: carry out the initial inspection within 50 flight hours after 12 April 2007 (unless it has already been done). After that, continue inspections at intervals not exceeding 100 flight hours or at the annual inspection, whichever comes first, until the definitive corrective action has been completed. If the definitive corrective action is required, it must be done before the aircraft flies again. (Compliance.)\n\n- The AD points operators to the LAVIASA Service Bulletin for the detailed inspection and repair procedures and references a related Argentine airworthiness directive. (Requirement; Notes.)\n\n**Why CASA says this matters (the stated purpose)**\n\n- The stated reason is that reports were received of severe corrosion and cracking of both horizontal stabiliser supports on several affected aircraft, creating an unsafe condition unless inspected and repaired. (Background.)\n\n**Practical implications, incentives and costs**\n\n- Who pays: aircraft owners/operators bear the cost of inspections, any repairs, parts and the aircraft downtime required. (Requirement; Compliance.)\n\n- Who decides and carries out the work: licensed maintenance personnel must perform inspections and corrective work following the LAVIASA Service Bulletin. CASA enforces compliance by making the AD mandatory. (Requirement; Compliance.)\n\n- Behavioural change required: operators must track flight hours to determine when the 1,500‑hour applicability threshold and the inspection intervals apply; schedule an inspection within the 50‑hour window; and plan for recurring inspections until repair. If defects are found, the aircraft must be grounded until the definitive repair is completed. (Applicability; Compliance.)\n\n- Direct costs and trade‑offs: inspections impose labour time and inspection tooling costs; corrective actions may require replacement parts, corrosion treatment or structural repairs and produce aircraft downtime. These are immediate, concentrated costs for owners; the safety benefit is the reduction in risk of structural failure of the stabiliser supports.\n\n- Implementation risks and compliance burden: the AD delegates the technical detail to an external Service Bulletin (LAVIASA SB). That creates dependence on access to the SB (contact emails are provided) and on the SB’s completeness. Operators must ensure accurate flight‑hour records and timely scheduling of repetitive inspections. If parts or approved repair instructions are scarce, repairs could cause longer grounding. The AD’s wording also requires care in interpretation: the AD refers to an ‘‘Initial’’ and a ‘‘Definitive’’ action in the SB and specifies differing compliance timings (50 flight hours then 100‑hour/annual repeats until definitive action). (Requirement; Compliance; Notes.)\n\n- Market effects: the requirement creates demand for maintenance labor and approved parts; independent maintenance organisations can perform the work if they follow the Service Bulletin and regulatory requirements. There is no direct restriction on ownership or operation beyond the inspection/repair obligations. (Requirement.)\n\n**Summary statement**\n\n- Mechanically, the AD mandates prompt and repeated inspections of horizontal stabiliser supports on specified older PA‑25 series aircraft and requires any detected corrosion or cracking to be remedied before further flight, using procedures in the LAVIASA Service Bulletin. Owners/operators pay the costs; maintenance organisations carry out the work; and CASA requires and enforces compliance to mitigate the reported unsafe condition. (Applicability; Requirement; Compliance; Background.)"},"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-25-42-horizontal-stabiliser-forward-and-aft-supports","history":"/api/acts/ad-pa-25-42-horizontal-stabiliser-forward-and-aft-supports/history","analysis":"/api/acts/ad-pa-25-42-horizontal-stabiliser-forward-and-aft-supports/analysis","conflicts":"/api/acts/ad-pa-25-42-horizontal-stabiliser-forward-and-aft-supports/conflicts","importantCases":"/api/acts/ad-pa-25-42-horizontal-stabiliser-forward-and-aft-supports/important-cases","documents":"/api/acts/ad-pa-25-42-horizontal-stabiliser-forward-and-aft-supports/documents"}}