{"id":"F2006B09119","name":"AD/DHC-6/31 Amdt 3 - Structural Component Inspection, Modification and Life Limitation","slug":"ad-dhc-6-31-amdt-3-structural-component-inspection-modification-and-life-limitation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115672,"registerId":"commonwealth-F2006B09119-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"2. Pre. Mod. 6/1117 Wing Assemblies","sectionType":"part","heading":"2. Pre. Mod. 6/1117 Wing Assemblies","content":"# 2. Pre. Mod. 6/1117 Wing Assemblies\n\n    If the previous inspection of the wing main spar, attachment lug fastener holes, conducted prior to 10 August 2000, was an eddy current inspection carried out in accordance with instructions supplied by Bombardier, conduct the repeat high frequency eddy current inspection in accordance with the schedule in PSM 1-6-11 Revision 5.\n\n    b. If the previous inspection of the wing main spar, attachment lug fastener holes, conducted prior to 10 August 2000, was an ultrasonic inspection carried out in accordance with Bombardier Service Bulletin 6/525, conduct the first high frequency eddy current inspection within 1,000 hours flight time or 2,000 flights, whichever occurs first, after the last ultrasonic inspection.","sortOrder":0},{"sectionNumber":"Post Mod 6/1117 and Post Mod 6/1630 Wing","sectionType":"part","heading":"Post Mod 6/1117 and Post Mod 6/1630 Wing Assemblies","content":"# Post Mod 6/1117 and Post Mod 6/1630 Wing Assemblies\n\nIf the inspection threshold for the lower wing skin, stringers and aft spar lower flange WS122 TO WS263 (ribs 8 to 20) has been exceeded or will be exceeded within 6 months after 10 August 2000, conduct the initial inspection within 500 hours flight time or 1,000 flights, whichever occurs first, but not later than 6 months after 10 August 2000.","sortOrder":1}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2356},"content_quality":"ok","complexity_score":7,"scope_assessment":{"changed":true,"description":"Amendment 3 expands the directive's scope beyond the original aircraft configuration to explicitly address distinct inspection requirements for wing assemblies that have undergone Modifications 6/1117 and 6/1630, creating separate compliance pathways for modified versus unmodified aircraft."},"complexity_factors":["Multiple conditional branches based on aircraft modification status (Pre-Mod 6/1117 vs Post-Mod 6/1117 and Post-Mod 6/1630)","Technical cross-references to external manufacturer documents (Bombardier Service Bulletin 6/525, PSM 1-6-11 Revision 5)","Dual compliance metrics requiring calculation of both flight hours and flight cycles (whichever occurs first)","Nested temporal thresholds including a fixed calendar date (10 August 2000) and relative time windows (6 months, 500/1,000/2,000 hours)","Specialized aeronautical engineering terminology (eddy current, ultrasonic, main spar, attachment lugs, stringers, flanges)"],"plain_english_summary":"This mandatory Airworthiness Directive affects owners and operators of DHC‑6 Twin Otters (especially aircraft with certain wing modifications) and requires high‑frequency eddy‑current inspections of critical wing structures. Inspection timing depends on each aircraft’s modification and inspection history; some aircraft face short, specific compliance windows.\n\nWhy it matters: the checks are intended to detect fatigue cracks in wing spars and fittings before they can cause catastrophic wing failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-31-amdt-3-structural-component-inspection-modification-and-life-limitation","history":"/api/acts/ad-dhc-6-31-amdt-3-structural-component-inspection-modification-and-life-limitation/history","analysis":"/api/acts/ad-dhc-6-31-amdt-3-structural-component-inspection-modification-and-life-limitation/analysis","conflicts":"/api/acts/ad-dhc-6-31-amdt-3-structural-component-inspection-modification-and-life-limitation/conflicts","importantCases":"/api/acts/ad-dhc-6-31-amdt-3-structural-component-inspection-modification-and-life-limitation/important-cases","documents":"/api/acts/ad-dhc-6-31-amdt-3-structural-component-inspection-modification-and-life-limitation/documents"}}