{"id":"F2006B08931","name":"AD/DH114/20 - Rear Engine Foot to Engine Mounting Bolts - Inspection and Retirement","slug":"ad-dh114-20-rear-engine-foot-to-engine-mounting-bolts-inspection-and-retirement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52509,"registerId":"commonwealth-F2006B08931-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DH114/20 - Rear Engine Foot to Engine Mounting Bolts - Inspection and Retirement","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)  DH114 (Heron) Series Aeroplanes\n\n \n\nAD/DH114/20 Rear Engine Foot to Engine Mounting NK\n\nBolts - Inspection and Retirement\n\n \n\nApplicability: All models.\n\n \n\nDocument: De Havilland TNS Heron (114) No. E.2. Compliance:  As detailed in the requirement document.\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\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive targeting a specific maintenance issue on a specific aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Extremely short document (approximately 150 words of substantive content)","Only one defined term implicitly referenced (the document number E.2)","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","Single, straightforward requirement: inspect and retire specific bolts per manufacturer instructions","No conditional logic, exceptions, or nested provisions","Applicability is absolute ('All models') with no exclusions or carve-outs"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order — issued by Australia's Civil Aviation Safety Authority (CASA) for a specific type of aircraft: the **De Havilland DH114 Heron** series.\n\n**What it does:**\nThe directive requires inspection and eventual replacement (\"retirement\") of specific bolts that attach the rear engine mounting foot to the engine on these planes. These bolts are critical structural components that keep the engine secured to the airframe.\n\n**Who it affects:**\n- Owners and operators of all De Havilland DH114 Heron aircraft models\n- Maintenance organisations servicing these aircraft\n- Pilots flying these aircraft (indirectly, as they must ensure compliance before flight)\n\n**Why it matters:**\nEngine mounting bolts are safety-critical. If they fail in flight, the engine could detach or shift, leading to catastrophic loss of control or power. This AD likely responds to discovered fatigue, corrosion, or manufacturing defects in these specific bolts. \"Retirement\" means the bolts must be replaced after a certain number of flight hours or cycles, regardless of apparent condition — a precaution against metal fatigue that isn't visible to inspectors.\n\n**Compliance:**\nOperators must follow the technical instructions in De Havilland document \"TNS Heron (114) No. E.2\" — this is the detailed engineering manual specifying exactly how and when to inspect and replace the bolts."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The provided text does not indicate any change from an earlier or different scope. The AD as published applies to all models of the DH114 Heron and defers procedural and technical specifics to De Havilland TNS Heron (114) No. E.2. There is no material in the supplied document that shows the scope has been expanded or narrowed from an original intent."},"complexity_factors":["Relies on an external requirement document (E.2) for all technical details (inspection methods, retirement criteria, timing), leaving the AD text minimal.","Applicability to all models increases potential variability in how different airframes or operators implement the requirement.","Operational impacts (scheduling, parts, labour) depend on unspecified content of E.2, creating implementation uncertainty.","Regulatory compliance requires record-keeping and demonstrable conformity with both the AD and E.2, which can vary by operator size and capability.","Potential interaction with other maintenance programs and regulatory reporting under Part 39 may require coordination across organisational processes."],"plain_english_summary":"This airworthiness directive makes inspection and retirement of the rear engine foot-to-engine mounting bolts mandatory on all De Havilland DH114 (Heron) aircraft, with detailed methods, retirement criteria and timing specified in De Havilland TNS Heron (114) No. E.2. It affects DH114 owners/operators, maintenance organisations and licensed engineers who must perform the work, bear the cost and keep records—potentially causing maintenance downtime and parts replacement depending on E.2’s requirements."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dh114-20-rear-engine-foot-to-engine-mounting-bolts-inspection-and-retirement","history":"/api/acts/ad-dh114-20-rear-engine-foot-to-engine-mounting-bolts-inspection-and-retirement/history","analysis":"/api/acts/ad-dh114-20-rear-engine-foot-to-engine-mounting-bolts-inspection-and-retirement/analysis","conflicts":"/api/acts/ad-dh114-20-rear-engine-foot-to-engine-mounting-bolts-inspection-and-retirement/conflicts","importantCases":"/api/acts/ad-dh114-20-rear-engine-foot-to-engine-mounting-bolts-inspection-and-retirement/important-cases","documents":"/api/acts/ad-dh114-20-rear-engine-foot-to-engine-mounting-bolts-inspection-and-retirement/documents"}}