{"id":"F2006B08939","name":"AD/DH114/29 Amdt 1 - Main Undercarriage - Main and Damper Jack Bolts - Inspection and Modification","slug":"ad-dh114-29-amdt-1-main-undercarriage-main-and-damper-jack-bolts-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52542,"registerId":"commonwealth-F2006B08939-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DH114/29 Amdt 1 - Main Undercarriage - Main and Damper Jack Bolts - Inspection and Modification","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)  \nDH114 (Heron) Series Aeroplanes\n\nAD/DH114/29\n\nAmdt 1\n\n  \n\nMain Undercarriage - Main and Damper NK Jack Bolts - Inspection and Modification\n\nApplicability: All Series 2 aircraft.\n\nRequirement: Inspect the attachment bolts at each end of the damper jack and at the top of the main jack for fatigue cracking as follows:\n\n    For aircraft fitted with attachment bolts P/No. 14-2U.299:-\n\n    (a) Remove the bolts and inspect for cracking around the centre grease hole using a magnetic particle method.\n\n    (b) Incorporate Modification No. 1536.\n\n    2. For aircraft fitted with attachment bolts P/No. 14-2U.631:-\n\nRemove the bolts and inspect for cracking around the centre grease hole using a magnetic particle method.\n\nCompliance: For Para. 1:\n\n    (a) For aircraft inspected in accordance with the previous issue of this Directive \\- within 300 hours time in service from the previous inspection; and\n\nFor all other aircraft \\- within 150 hours time in service after 31 May 1972; and\n\nFor all other aircraft \\- thereafter at intervals not exceeding 300 hours time in service.\n\n    (b) Before 31 December 1972\\. For Para. 2:\n\nWithin 2400 hours time in service after the incorporation of modification 1536 and thereafter at intervals not exceeding 2400 hours time in service.","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":3,"scope_assessment":{"changed":false,"description":"This is an amendment (Amdt 1) to an existing Airworthiness Directive. The scope remains tightly focused on the original safety issue: preventing fatigue failure of specific undercarriage bolts in DH114 Heron aircraft. The amendment appears to refine inspection intervals and compliance dates without expanding beyond the original mechanical safety purpose."},"complexity_factors":["Multiple part numbers with different requirements (two distinct bolt types)","Tiered compliance deadlines based on prior inspection history","Cross-references to external modification number (Mod 1536) without explanation","Mixed units of measurement (flight hours and calendar dates)","Nested conditional logic for compliance timing (Para 1(a) has three sub-conditions)"],"plain_english_summary":"This AD mandates inspection and, where required, modification of the main landing‑gear bolts on de Havilland DH114 Heron Series 2 aeroplanes. It targets bolts that can develop fatigue cracks around grease holes which, if undetected, could lead to bolt failure and landing‑gear collapse.\n\nIt affects owners, operators and maintainers of Heron Series 2 aircraft in Australia (charter operators, historic owners, museums) and requires timely magnetic particle inspection and installation of an engineering modification where specified."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This amendment adds a mandatory modification requirement (Modification No.1536) for bolts P/No. 14-2U.299 and establishes distinct inspection intervals, including a 2400‑hour interval after incorporation of the modification for P/No. 14-2U.631 (see Requirement and Compliance: 'Incorporate Modification No. 1536' and 'For Para. 2: Within 2400 hours ... after the incorporation of modification 1536'). It also ties initial intervals to whether the aircraft was inspected under the previous issue ('For aircraft inspected in accordance with the previous issue ...')."},"complexity_factors":["Part-number specific requirements: separate rules for P/No. 14-2U.299 and P/No. 14-2U.631 (Requirement).","Mandatory incorporation of Modification No.1536 for P/No. 14-2U.299 (Requirement: 'Incorporate Modification No. 1536').","Specified inspection method (magnetic particle) requiring bolt removal and non‑destructive testing (Requirement: 'inspect ... using a magnetic particle method').","Multiple, staggered compliance intervals tied to prior inspections, calendar dates and modification status (Compliance: Para.1(a)/(b) and 'For Para. 2').","Applicability limited to Series 2 aircraft and references to a previous Directive, creating dependency on historical compliance records (Applicability / Compliance: 'For aircraft inspected in accordance with the previous issue').","Operational impact on maintenance scheduling and potential parts downtime due to bolt removal, testing and modification."],"plain_english_summary":"Mandates removal and magnetic-particle inspection of the main and damper jack attachment bolts on DH114 (Heron) Series 2 aircraft, and requires incorporation of Modification No.1536 for bolts P/No. 14-2U.299. It sets initial and recurring inspection intervals (150–300 hours depending on prior inspection) and a 2400‑hour interval after modification for bolts P/No. 14-2U.631. Operators must perform the inspections, fit the modification where required, and schedule recurring checks under the stated time limits."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dh114-29-amdt-1-main-undercarriage-main-and-damper-jack-bolts-inspection-and-modification","history":"/api/acts/ad-dh114-29-amdt-1-main-undercarriage-main-and-damper-jack-bolts-inspection-and-modification/history","analysis":"/api/acts/ad-dh114-29-amdt-1-main-undercarriage-main-and-damper-jack-bolts-inspection-and-modification/analysis","conflicts":"/api/acts/ad-dh114-29-amdt-1-main-undercarriage-main-and-damper-jack-bolts-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-dh114-29-amdt-1-main-undercarriage-main-and-damper-jack-bolts-inspection-and-modification/important-cases","documents":"/api/acts/ad-dh114-29-amdt-1-main-undercarriage-main-and-damper-jack-bolts-inspection-and-modification/documents"}}