{"id":"F2006B07607","name":"AD/WRI/1 - Accessory Drive Gear - Modification","slug":"ad-wri-1-accessory-drive-gear-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":50297,"registerId":"commonwealth-F2006B07607-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/WRI/1 - Accessory Drive Gear - Modification","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nWright Piston Engines\n\nAD/WRI/1 Accessory Drive Gear \\- Modification NK\n\nApplicability: GR1820-200 series.\n\nRequirement: 1. Modify engines fitted with a two speed supercharger drive in accordance with either of the following sub-paragraphs:\n\n    (a) Replace accessory drive gear P/N 62336 with modified gear P/N 62336J; or\n\n    (b) Modify the supercharger drive for single speed operation only.\n\n    2. Modify engines fitted with a single speed supercharger drive in accordance with either of the following sub-paragraphs:\n\n    (a) Replace accessory drive gear P/N 62336 with modified gear P/N 62336J; or\n\n    (b) Replace existing gear P/N 62336 with a new gear P/N 62336 which has been reworked in accordance with paragraph 3 of this Order.\n\n    3. Rework gears P/N 62336 to remove all signs of grinding marks in the fillets at the roots of the gear teeth. Great care must be taken during the rework and the polishing operation must be confined to the radius of each fillet and must NOT extend up the flank of the tooth. The gear shall be checked with the aid of an approved crack detecting apparatus prior to installation in the engine. New gears only shall be reworked and unmodified gears which have been in service shall be rejected; or\n\nANO 106.1.17.4.5.1\n\nCompliance: Forthwith.","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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific engine series. It has not expanded beyond its original purpose of mandating gear modifications to prevent fatigue failures."},"complexity_factors":["Very short document (under 300 words)","Only 3 defined part numbers (62336, 62336J, GR1820-200)","Simple conditional structure based on two engine variants (two-speed vs single-speed supercharger)","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Single compliance deadline ('Forthwith') with no exceptions or phased implementation","Technical but precise instructions (polishing confined to fillet radius, crack detection requirement)"],"plain_english_summary":"This CASA Airworthiness Directive orders immediate modification or replacement of the accessory drive gear on Wright GR1820-200 series piston engines. Operators must act forthwith because existing gears show grinding marks that can crack and cause catastrophic engine seizure or loss of accessories in flight.\n\nThe directive requires fitted fixes (an improved gear or supercharger conversion) or, for single-speed engines, replacement with or careful polishing of unused gears to remove the defect."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument applies only to Wright GR1820‑200 series engines and prescribes corrective modifications, replacements, rework and inspection requirements. It does not expand the stated applicability beyond that engine series; it changes maintenance obligations and allowable parts/procedures but does not alter the population of affected engines."},"complexity_factors":["Multiple alternative compliance paths depending on supercharger type (Requirement 1 vs 2).","Part‑number specific actions required (P/N 62336 vs P/N 62336J).","Technical rework constraints on fillet polishing and prohibition of polishing up the tooth flank (Requirement 3).","Mandatory crack detection inspection with an approved apparatus before installation (Requirement 3).","Rejection of in‑service unmodified gears—only new gears may be reworked (Requirement 3).","Immediate compliance deadline ('Forthwith') increases operational and scheduling pressure (Compliance)."],"plain_english_summary":"_What it changes:_ Requires owners/operators of Wright GR1820-200 engines to either replace accessory drive gear P/N 62336 with modified P/N 62336J, convert a two‑speed supercharger to single‑speed, or have new gears reworked and crack‑tested; in‑service unmodified gears must be rejected. (Reqs 1–3.)\n\nWho it affects and why it matters: This directly affects aircraft operators and maintenance providers of GR1820‑200 engines, who must pay for parts, rework, inspections and immediate compliance to meet airworthiness standards."}},"importantCases":[],"_links":{"self":"/api/acts/ad-wri-1-accessory-drive-gear-modification","history":"/api/acts/ad-wri-1-accessory-drive-gear-modification/history","analysis":"/api/acts/ad-wri-1-accessory-drive-gear-modification/analysis","conflicts":"/api/acts/ad-wri-1-accessory-drive-gear-modification/conflicts","importantCases":"/api/acts/ad-wri-1-accessory-drive-gear-modification/important-cases","documents":"/api/acts/ad-wri-1-accessory-drive-gear-modification/documents"}}