{"id":"F2006B06004","name":"AD/PA-44/13 - Main Landing Gear - Trunnion Housing","slug":"ad-pa-44-13-main-landing-gear-trunnion-housing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114402,"registerId":"commonwealth-F2006B06004-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-44/13 - Main Landing Gear - Trunnion Housing","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPiper PA-44 (Seminole) Series Aeroplanes\n\nAD/PA-44/13 Main Landing Gear \\- Trunnion Housing 10/94\n\nApplicability: PA-44-180 Seminole Serial Numbers 44-7995001 to 44-8195026 and PA-44-180T Turbo Seminole Serial Number 44-8107001 to 44-8207020, unless equipped with main landing gear trunnion housings bearing the forging stamp number 02599-2.\n\nRequirement: 1. Clean and strip paint from the inspection area as defined in Sketch A and Sketch B of Piper SB 787B. Inspect for cracks using fluorescent dye penetrant per CAO\n\n108.10. Perform a detailed visual inspection using a 10X glass for grinding or machining marks. Remove any marks detected with 180 grit aluminium oxide paper. Polish area with 600 grit or finer aluminium oxide paper. Treat with Alodine 1200 (or equivalent), prime with a chromate primer and finish paint to match existing scheme.\n\n    2. Clean and strip paint from the inspection area as defined in Sketch A and Sketch B of Piper SB 787B. Inspect for cracks using fluorescent dye penetrant per CAO\n\n108.10. Prime with a chromate primer and finish paint to match existing scheme.\n\n    3. Replace main landing gear trunnion with new replacement part number components as defined in Piper SB 787B.\n\nNote: FAA AD 94-13-11 refers.\n\nCompliance: 1. Action in accordance with Requirement 1 before 500 hours time in service or within 50 hours time in service from 15 September 1994 whichever is the later.\n\n    2. Action in accordance with Requirement 2 at intervals not exceeding 100 hours time in service.\n\n    3. If the main landing gear trunnion hours cannot be determined the airframe hours may be substituted. Action in accordance with Requirement 3 before 2000 hours time in service, except that main landing gear trunnions that have exceeded 2000 hours time in service may remain in service until 2500 hours time in service provided:\n\n    Replacement parts have been ordered and are unavailable.\n\n    b. Repeat inspections are performed at 10 hour time in service intervals and no cracks are detected. In this instance the requirement to paint the trunnion between inspections may be deleted.\n\n    c. Replacement is completed within 5 hours time in service of the parts becoming available.\n\nReplacement with new part number trunnion housings as listed in Piper SB 787B with embossed forging number 02599-2, cancels all requirements of this AD.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBackground: Cracks have developed in the main landing gear trunnion housings on the aft side at the lower end of the fillet. Though Piper have made design changes to these components cracks have still continued to occur. This AD inspects existing components and replaces them with further improved components.","sortOrder":0}],"analysis":{"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"},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The AD's operational scope aligns with its stated objective: inspect and replace trunnion housings on the listed PA‑44 serial numbers unless already fitted with forging stamp 02599‑2. It does not broaden applicability beyond those aircraft; it specifies inspection/repair methods, compliance intervals, and exceptional allowances for parts availability (Applicability; Requirement; Compliance; Replacement)."},"complexity_factors":["Applicability is conditional on serial numbers and forging stamp 02599-2, creating a binary eligibility check for many aircraft (Applicability).","Multiple procedural requirements for inspections and repairs: fluorescent dye penetrant per CAO 108.10 and detailed surface preparation (180 grit, 600 grit, Alodine 1200, chromate primer) (Requirement 1).","Several distinct compliance timelines and intervals (initial 50–500 hours window, recurring 100‑hour inspections, replacement by 2000–2500 hours with exceptions) impose scheduling complexity (Compliance 1–3).","Contingency rules if trunnion hours unknown (airframe hours substitution) and if replacement parts are delayed (short 10‑hour inspection repeats, temporary omission of repainting) introduce operational discretion (Compliance 3).","Dependency on external technical documents and standards (Piper SB 787B; CAO 108.10; FAA AD referenced) requires access to and adherence to third‑party procedures.","Replacement cancels the AD for that aircraft, creating a one‑time capital cost tradeoff vs ongoing inspection burden (Replacement paragraph).","Costs fall on owners/operators (inspection, labour, parts); maintenance organisations must certify work to the stated standards (Applicability; Requirement; Compliance)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of specified Piper PA‑44 Seminole serial numbers to inspect, repair and ultimately replace main landing gear trunnion housings that do not bear forging stamp 02599-2. It prescribes inspection method (fluorescent dye penetrant), surface preparation, painting and approved replacement parts.\n\nThe AD is intended to detect and remove fatigue cracks to maintain airworthiness. Owners/operators bear inspection, repair and replacement costs; maintenance organisations must follow Piper SB 787B and CAO 108.10; CASA enforces compliance."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a focused, narrow scope. It addresses a specific safety defect in specific aircraft models through inspection and replacement requirements. The scope remains tightly constrained to the identified landing gear issue without expansion into unrelated systems or operational matters."},"complexity_factors":["Multiple compliance pathways (Requirements 1, 2, and 3) with different timelines and conditions","Cross-references to external documents: Piper Service Bulletin 787B, CAO 108.10 (Civil Aviation Order), and FAA AD 94-13-11","Conditional logic for compliance deadlines: 'whichever is the later' and substitution rules when part hours are unknown","Nested exception in Requirement 3 allowing extended service to 2,500 hours subject to three sub-conditions (parts ordered but unavailable, 10-hour interval inspections, and 5-hour replacement deadline)","Specific technical procedures requiring specialized knowledge (fluorescent dye penetrant inspection, Alodine treatment, chromate priming, specific grit papers)","Cancellation clause triggered by specific part identification (forging number 02599-2)"],"plain_english_summary":"Owners and operators of specified Piper PA-44 Seminole and Turbo Seminole aircraft must inspect and, if necessary, replace the main landing gear trunnion housing after cracks were discovered that can cause gear failure. The directive requires an initial dye/magnification inspection within 500 flight hours (or 50 hours from Sept 1994), recurring checks every 100 hours, and replacement with an improved forging before 2,000 hours (2,500 in limited cases with extra checks). It affects aircraft without the improved forging and aims to prevent catastrophic landing‑gear failures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-44-13-main-landing-gear-trunnion-housing","history":"/api/acts/ad-pa-44-13-main-landing-gear-trunnion-housing/history","analysis":"/api/acts/ad-pa-44-13-main-landing-gear-trunnion-housing/analysis","conflicts":"/api/acts/ad-pa-44-13-main-landing-gear-trunnion-housing/conflicts","importantCases":"/api/acts/ad-pa-44-13-main-landing-gear-trunnion-housing/important-cases","documents":"/api/acts/ad-pa-44-13-main-landing-gear-trunnion-housing/documents"}}