{"id":"F2006B01912","name":"AD/A320/21 - Main Landing Gear Wheel Axle","slug":"ad-a320-21-main-landing-gear-wheel-axle","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41134,"registerId":"commonwealth-F2006B01912-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/A320/21 - Main Landing Gear Wheel Axle","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)  \nAirbus Industrie A319, A320 and A321 Series Aeroplanes\n\nAD/A320/21 Main Landing Gear Wheel Axle 10/91\n\nApplicability: Models A321-111, A320-211, A320-231, Serial Numbers MSN 002 to 044, 052 to 055, 059 to 073, 076 to 078 and 081, fitted with twin wheel main landing gear.\n\nRequirement: Action in accordance with the Technical Requirements of DGAC AD 90-096-010 (B), dated 2 May 1990.\n\nNote: Airbus Industry Service Bulletin A320-32-1031, Revision 1, dated 19 March 1990, refers.\n\nCompliance: Prior to the accumulation of 6 600 flights.\n\nBackground: The chrome plate grinding process used during manufacture may have caused overheating of the main landing gear axle and introduced residual stresses in the flange to axle radius. In some sliding tube assemblies, this has caused cracks under the chrome plating in the area of the brake mounting flange, with a subsequent reduction in safe operating life.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2548},"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This airworthiness directive maintains its original narrow scope addressing a specific manufacturing defect in early production Airbus A320 family aircraft. There is no indication of scope creep beyond the original safety issue concerning chrome-plated main landing gear axles."},"complexity_factors":["Incorporation by reference of external technical documents (DGAC AD 90-096-010(B) and Airbus Service Bulletin A320-32-1031) without reproducing their contents","Highly specific serial number applicability requiring cross-referencing (MSN 002-044, 052-055, 059-073, 076-078, 081)","Technical aviation terminology requiring specialized engineering knowledge (chrome plate grinding, residual stresses, sliding tube assemblies)","Dual conditional applicability limiting scope to specific models, specific serial numbers, and specific landing gear configuration"],"plain_english_summary":"CASA issues a mandatory Airworthiness Directive requiring immediate inspection and repair of main landing gear axles on certain early-model Airbus A319/A320/A321 twin-wheel aircraft. Manufacturing overheating during chrome plating can cause hidden cracks at the brake attachment, risking axle failure.\n\nThe AD applies to owners/operators of specified MSNs (early serial ranges) and mandates inspections and corrective work per DGAC AD 90-096-010(B)/Airbus SB A320-32-1031, to be completed before 6,600 flights."}},"importantCases":[],"_links":{"self":"/api/acts/ad-a320-21-main-landing-gear-wheel-axle","history":"/api/acts/ad-a320-21-main-landing-gear-wheel-axle/history","analysis":"/api/acts/ad-a320-21-main-landing-gear-wheel-axle/analysis","conflicts":"/api/acts/ad-a320-21-main-landing-gear-wheel-axle/conflicts","importantCases":"/api/acts/ad-a320-21-main-landing-gear-wheel-axle/important-cases","documents":"/api/acts/ad-a320-21-main-landing-gear-wheel-axle/documents"}}