{"id":"F2006B06166","name":"AD/PDH/7 - Barrel Support Blocks - Modification","slug":"ad-pdh-7-barrel-support-blocks-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46999,"registerId":"commonwealth-F2006B06166-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PDH/7 - Barrel Support Blocks - Modification","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 - 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Propellers - Variable Pitch - De Havilland\n\n \n\nAD/PDH/7 Barrel Support Blocks - Modification 3/68\n\nApplicability: All model PD136/212/1, PD170/212/1 and PD175/212/1 propellers fitted to DH114 aircraft.\n\n \n\nDocument: Hawker Siddeley MNS Series 2 BCS No. 87 (Mod. No. 29104).\n\n \n\nCompliance: Before installation in an aircraft following next overhaul completed after 21 March 1968.\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":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1386},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This directive maintains its original narrow scope targeting specific De Havilland propeller models for a single mechanical modification. No evidence of expansion beyond the original technical safety intent."},"complexity_factors":["Extremely brief instrument containing only 3 operative clauses (Applicability, Document reference, Compliance)","Single straightforward compliance deadline tied to maintenance events","Technical terminology requires aviation engineering knowledge to interpret the physical modification","External incorporation of manufacturer specifications without reproducing the technical content in the directive itself"],"plain_english_summary":"This Airworthiness Directive (AD) mandates a **safety modification to propellers** used on specific De Havilland aircraft.\n\n**Who it affects:**\nOwners and operators of DH114 aircraft fitted with PD136/212/1, PD170/212/1, or PD175/212/1 model propellers.\n\n**What it requires:**\nYou must install modified **barrel support blocks** (internal components that secure the propeller blade barrels) whenever the propeller is next overhauled after 21 March 1968. The specific technical instructions are contained in the referenced Hawker Siddeley engineering document (Modification No. 29104).\n\n**Why it matters:**\nThe directive ensures these critical structural components meet updated safety standards to prevent potential mechanical failures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pdh-7-barrel-support-blocks-modification","history":"/api/acts/ad-pdh-7-barrel-support-blocks-modification/history","analysis":"/api/acts/ad-pdh-7-barrel-support-blocks-modification/analysis","conflicts":"/api/acts/ad-pdh-7-barrel-support-blocks-modification/conflicts","importantCases":"/api/acts/ad-pdh-7-barrel-support-blocks-modification/important-cases","documents":"/api/acts/ad-pdh-7-barrel-support-blocks-modification/documents"}}