{"id":"F2006B03059","name":"AD/B747/157 Amdt 1 - P&W JT9D Aft Engine Mount Tangential Link","slug":"ad-b747-157-amdt-1-p-w-jt9d-aft-engine-mount-tangential-link","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42418,"registerId":"commonwealth-F2006B03059-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/157 Amdt 1 - P&W JT9D Aft Engine Mount Tangential Link","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)  \nBoeing 747 Series Aeroplanes\n\nAD/B747/157\n\nAmdt 1\n\n  \nP&W JT9D Aft Engine Mount Tangential Link 7/96\n\nApplicability: Model 747 series, with P&W JT9D engines, line positions 1 to 668 except \\-70s. Requirement: Action in accordance with Boeing 747 ASB 747-71A2277.\n\nNote: FAA AD 96-03-01 R1 Amdt 39-9538 refers.\n\nCompliance: Unless the initial inspection has already been accomplished in accordance with the previous issue of this Directive; as specified in the Requirement Document.\n\nThe compliance of the previous issue of this Directive required an initial inspection within 90 days after 13 March 1996. This amendment is effective from 20 June 1996.\n\nBackground: The tangential link upper bolt was found to have backed out, following lubrication of the threads and/or inadequate nut torque, which allowed the nut to rotate and disengage.\n\nAmendment 1 is issued to reflect a revision of the associated country of origin AD which was issued to clarify an error in the text.\n\nThe original issue of this Airworthiness Directive became effective on 13 March 1996.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1382},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The amendment merely corrects a textual error in the referenced foreign directive; it does not expand the scope beyond the original safety concern regarding engine mount bolt integrity."},"complexity_factors":["Cross-references to external technical documents (Boeing Alert Service Bulletin and FAA Airworthiness Directive)","Specific aircraft lineage restrictions (line positions 1-668, excluding -70s models)","Amendment structure referencing previous directive versions and compliance history","Technical aviation terminology requiring specialized engineering knowledge to execute"],"plain_english_summary":"This mandatory Civil Aviation Safety Authority airworthiness directive requires owners/operators of Boeing 747s with Pratt & Whitney JT9D engines (line positions 1–668, excluding -70 series) to inspect and, if needed, correct the tangential link upper bolt on the rear engine mount to prevent it backing out. \n\nThis is Amendment 1, which only corrects wording from the FAA text; the safety requirement and compliance timeline remain unchanged."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-157-amdt-1-p-w-jt9d-aft-engine-mount-tangential-link","history":"/api/acts/ad-b747-157-amdt-1-p-w-jt9d-aft-engine-mount-tangential-link/history","analysis":"/api/acts/ad-b747-157-amdt-1-p-w-jt9d-aft-engine-mount-tangential-link/analysis","conflicts":"/api/acts/ad-b747-157-amdt-1-p-w-jt9d-aft-engine-mount-tangential-link/conflicts","importantCases":"/api/acts/ad-b747-157-amdt-1-p-w-jt9d-aft-engine-mount-tangential-link/important-cases","documents":"/api/acts/ad-b747-157-amdt-1-p-w-jt9d-aft-engine-mount-tangential-link/documents"}}