{"id":"F2006B08865","name":"AD/DH 104/20 - Landing Gear Actuator Pistons - Inspections and Replacement","slug":"ad-dh-104-20-landing-gear-actuator-pistons-inspections-and-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52065,"registerId":"commonwealth-F2006B08865-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DH 104/20 - Landing Gear Actuator Pistons - Inspections and Replacement","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  DH 104 (Dove) Series Aeroplanes\n\n \n\nAD/DH 104/20 Landing Gear Actuator Pistons - Inspections\n\nand Replacement\n\n\n8/71\n\n \n\nApplicability: All models fitted with Dunlop actuators P/N AH 8463 and AC 11130 in which pistons P/N AHO 19742 are installed.\n\n \n\nRequirement: 1. Remove the piston from the jack and inspect piston crown for signs of cracking.\n\n \n\n2. Remove from service Dunlop pistons P/No. AHO 19742. Compliance: For para. 1 - At intervals not exceeding 200 landings.\n\nFor para. 2 - Whenever a cracked piston crown is detected or at intervals not exceeding 10,000 landings whichever occurs first.\n\n \n\nNote: Incorporation of Dove Modification No. 1144 cancels these requirements.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1394},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow technical scope—mandating specific safety actions for a particular aircraft component. It has not expanded beyond its intended purpose of preventing landing gear failures on the specified DH 104 models."},"complexity_factors":["Specific aviation part number references requiring technical verification (P/N AH 8463, AC 11130, AHO 19742)","Dual compliance intervals with conditional logic (200 landings for inspection vs 10,000 for replacement)","Exception clause referencing external technical modification standard (Dove Modification No. 1144)","Industry-specific terminology (actuator pistons, jack, piston crown, landings)"],"plain_english_summary":"**What this does:** This directive mandates safety inspections and part replacements for the landing gear on specific vintage De Havilland DH 104 \"Dove\" aircraft to prevent mechanical failures.\n\n**Who it affects:** Owners and operators of DH 104 Dove aircraft fitted with specific Dunlop landing gear actuators (part numbers AH 8463 and AC 11130) that contain pistons marked AHO 19742.\n\n**What you must do:**\n- **Inspect:** Every 200 landings, remove the piston from the actuator (called a \"jack\" here) and examine the top surface (\"crown\") for cracks.\n- **Replace:** Remove the specified pistons from service immediately if you find cracks, or replace them every 10,000 landings at the latest—whichever comes first.\n\n**The exception:** If your aircraft has been modified according to \"Dove Modification No. 1144,\" you can ignore these requirements entirely."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dh-104-20-landing-gear-actuator-pistons-inspections-and-replacement","history":"/api/acts/ad-dh-104-20-landing-gear-actuator-pistons-inspections-and-replacement/history","analysis":"/api/acts/ad-dh-104-20-landing-gear-actuator-pistons-inspections-and-replacement/analysis","conflicts":"/api/acts/ad-dh-104-20-landing-gear-actuator-pistons-inspections-and-replacement/conflicts","importantCases":"/api/acts/ad-dh-104-20-landing-gear-actuator-pistons-inspections-and-replacement/important-cases","documents":"/api/acts/ad-dh-104-20-landing-gear-actuator-pistons-inspections-and-replacement/documents"}}