{"id":"F2006B10551","name":"AD/HS 748/17 - Engine Subframe Eye Bolt","slug":"ad-hs-748-17-engine-subframe-eye-bolt","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116365,"registerId":"commonwealth-F2006B10551-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HS 748/17 - Engine Subframe Eye Bolt","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)  British Aerospace (Hawker Siddeley) HS 748 Series Aeroplanes\n\n \n\nAD/HS 748/17 Engine Subframe Eye Bolt 5/95\n\nApplicability: All HS748 Aircraft.\n\n \n\nRequirement: 1. On both left and right engine subframe assemblies inspect the installation of the eye bolt (P/N 14b.0.3975) into the “Y” plate (P/N 14a.0.3975) in accordance with British Aerospace Mandatory Service Bulletin (MSB) 54/31.\n\n \n\n2. Rectify any deficient eye bolt installations in accordance with British Aerospace MSB 54/31.\n\n \n\nNote: CAA (UK) AD 009-08-88 refers.\n\n \n\nCompliance: 1. Inspect before 11 May 1995.\n\n \n\n2. Rectify, if required, within 60 days of the Requirement 1 inspection.\n\n \n\nBackground: An in-service failure of an eye bolt revealed the possibility of incorrect bedding of the eye bolt head to the sub-frame “Y” plate.\n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete airworthiness directive addressing a specific safety-critical defect on a particular aircraft type. It has not expanded beyond its original purpose of ensuring proper installation of engine subframe eye bolts."},"complexity_factors":["Single, specific mechanical component addressed (one bolt type on one aircraft series)","Only 2 substantive requirements (inspect and rectify)","No defined terms section","No cross-references to other legislation (only references a British Aerospace service bulletin and a UK aviation authority document)","Clear, unconditional compliance dates","Total length: approximately 150 words"],"plain_english_summary":"This is a **safety directive for aircraft maintenance** that applies to all British Aerospace HS 748 aeroplanes operating in Australia.\n\n**What it does:**\n- Requires aircraft operators to inspect a specific bolt (called an \"eye bolt\") on both left and right engine subframe assemblies\n- The inspection checks whether the bolt is properly seated against a metal plate (the \"Y\" plate)\n- If the bolt is incorrectly installed, it must be fixed within 60 days\n\n**Who it affects:**\n- Owners and operators of HS 748 aircraft in Australia\n- Licensed aircraft maintenance engineers who perform the inspections\n\n**Why it matters:**\nAn eye bolt failed in actual use, revealing that some bolts may not be properly bedded (seated) against the plate. A failed bolt could cause the engine subframe to detach, creating a serious flight safety risk. This directive prevents that failure by mandating inspection and correction.\n\n**Key deadlines:**\n- Inspection deadline: 11 May 1995\n- Repair deadline: Within 60 days of inspection if problems found"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive's scope as written — inspecting and rectifying eye bolt installations on all HS 748 aircraft — aligns with the stated background purpose of addressing an observed in‑service eye bolt failure (Applicability; Requirement 1; Requirement 2; Background). There is no indication in the text that the AD expands or narrows that original safety-focused remit."},"complexity_factors":["Simple, prescriptive requirements: an inspection and corrective action only (Requirement 1; Requirement 2).","Fixed, short compliance deadlines that create scheduling risk (Compliance 1; Compliance 2).","Dependence on an external technical document (British Aerospace MSB 54/31) for the detailed method (Requirement 1; Requirement 2).","Applicability to all HS 748 aircraft makes the universe of affected parties large but the action uniform (Applicability).","The term 'deficient' installation requires technical judgement during inspection (Requirement 2)."],"plain_english_summary":"The directive requires every HS 748 to have the engine subframe eye bolt installation inspected on both left and right “Y” plates and any deficiencies corrected per British Aerospace MSB 54/31. Inspections must be done by 11 May 1995 and repairs completed within 60 days of inspection. It affects HS 748 owners/operators, who bear costs and downtime; it was issued after an in‑service eye bolt failure revealed improper bedding."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-748-17-engine-subframe-eye-bolt","history":"/api/acts/ad-hs-748-17-engine-subframe-eye-bolt/history","analysis":"/api/acts/ad-hs-748-17-engine-subframe-eye-bolt/analysis","conflicts":"/api/acts/ad-hs-748-17-engine-subframe-eye-bolt/conflicts","importantCases":"/api/acts/ad-hs-748-17-engine-subframe-eye-bolt/important-cases","documents":"/api/acts/ad-hs-748-17-engine-subframe-eye-bolt/documents"}}