{"id":"F2006B10571","name":"AD/HS 748/5 - Engine Subframe Tubular Struts","slug":"ad-hs-748-5-engine-subframe-tubular-struts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116405,"registerId":"commonwealth-F2006B10571-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HS 748/5 - Engine Subframe Tubular Struts","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)  \nBritish Aerospace (Hawker Siddeley) HS 748 Series Aeroplanes\n\nAD/HS 748/5 Engine Subframe Tubular Struts 13/94\n\nApplicability: All engine sub frames which have been installed on aircraft longer than 6 years, and engine sub frames whose previous radiographic examination took place more than 7 years ago.\n\nRequirement: Action in accordance with Jetstream Aircraft Mandatory Service Bulletin HS748-54/25.\n\nNote: UK CAA AD 0119 refers.\n\nCompliance: For engine sub frames which have exceeded 6 years but not 10 years from new, or from the date of the last scheduled inspection, or from the date of sub frame replacement, the next radiographic inspection must be done within the following periods from 8 December 1994:\n\n    In excess of 6 years but not exceeding 8 years \\- examine prior to 8 December 1995.\n\n    b. In excess of 8 years but not exceeding 9 years \\- examine prior to 8 September 1995.\n\n    c. In excess of 9 years but not exceeding 10 years \\- examine prior to 8 June 1995.\n\nBackground: Internal corrosion in the tubes of several sub frame struts has been revealed following the current scheduled radiographic examination of the engine sub frame.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, time-limited safety directive issued in 1994 with a specific technical purpose. It has not expanded beyond its original intent of mandating corrosion inspections on HS 748 engine subframes. The scope remains tightly focused on the identified safety issue."},"complexity_factors":["Single, specific technical requirement with clear applicability criteria","Three-tiered compliance deadline structure based on equipment age","One external cross-reference to manufacturer service bulletin (HS748-54/25)","One international cross-reference to UK CAA AD 0119","No defined terms section — uses plain technical language","Short document (approximately 200 words) with single purpose"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of British Aerospace HS 748 aircraft to carry out radiographic (X‑ray) inspections of engine subframe tubular struts per Jetstream Aircraft Mandatory Service Bulletin HS748‑54/25. It applies to subframes installed over six years or not X‑rayed within seven years; inspection deadlines vary by subframe age (June–December 1995 windows).\n\nThe action responds to discovered internal corrosion that can weaken engine mounts, and aligns Australia with the UK CAA directive."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD text itself does not indicate any change from a prior scope. It defines applicability (subframes >6 years or with last radiograph >7 years) and prescribes inspection deadlines and a service bulletin; no comparison to an earlier scope or broadened/narrowed coverage is provided in the document."},"complexity_factors":["Technical inspection requirement (radiographic) needs specialised equipment and expertise.","Staggered compliance deadlines tied to subframe age bands and a fixed reference date (8 December 1994) increase scheduling complexity.","Applicability uses multiple triggers (installed >6 years; previous radiograph >7 years) creating record-keeping and tracking burdens.","Requirement delegates procedural detail to an external Mandatory Service Bulletin (HS748-54/25), creating dependence on that document.","Cross-reference to UK CAA AD 0119 requires alignment with an overseas directive for context or rationale.","Operational impact on operators (inspection costs, aircraft downtime, possible repairs/replacement) adds practical complexity.","Legislative drafting is short and direct, lowering legal interpretive complexity."],"plain_english_summary":"This Airworthiness Directive requires operators of HS 748 aeroplanes to carry out radiographic inspections of engine subframe tubular struts per Jetstream Mandatory Service Bulletin HS748-54/25 when a subframe is over 6 years old or its last radiographic exam was more than 7 years ago (Requirement; Compliance). Staggered deadlines from 8 December 1994 depend on the subframe’s age. Operators pay inspection and repair costs, must schedule inspections and retain age/inspection records, and may remove or replace subframes if internal corrosion is found (Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hs-748-5-engine-subframe-tubular-struts","history":"/api/acts/ad-hs-748-5-engine-subframe-tubular-struts/history","analysis":"/api/acts/ad-hs-748-5-engine-subframe-tubular-struts/analysis","conflicts":"/api/acts/ad-hs-748-5-engine-subframe-tubular-struts/conflicts","importantCases":"/api/acts/ad-hs-748-5-engine-subframe-tubular-struts/important-cases","documents":"/api/acts/ad-hs-748-5-engine-subframe-tubular-struts/documents"}}