{"id":"F2006B09685","name":"AD/F27/117 Amdt 1 - Engine Nacelles - Upper Brace Struts","slug":"ad-f27-117-amdt-1-engine-nacelles-upper-brace-struts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115832,"registerId":"commonwealth-F2006B09685-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F27/117 Amdt 1 - Engine Nacelles - Upper Brace 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)  \nFokker F27 Series Aeroplanes\n\nAD/F27/117\n\nAmdt 1\n\n  \nEngine Nacelles \\- Upper Brace Struts 9/89\n\nDM\n\nApplicability: F27 S/Nos. 10102 to 10307 inclusive, 10308 to 10340 inclusive, and 10342 to 10360 inclusive.\n\nRequirement: Action in accordance with Fokker S.B. F27/54-44 Revision 1.\n\nNote 1: Aircraft inspected in accordance with the initial issue of SB F27/54-44 do not require any additional inspection as a result of Revision 1.\n\nNote 2: RLD AD 88-42 Issue 2 refers.\n\nCompliance: For aircraft S/Nos 10102 to 10307 inclusive: Prior to 31 May 1989.\n\nFor all other affected Aircraft: Prior to 31 July 1989.\n\nBackground: There has been a failure of a P/No. 1107-196-401 strut that could have resulted in engine separation. The failed strut was found to be of pre-production configuration. It is possible that the pre-production strut may have been fitted to some aircraft during incorporation of S.B. F27/54-26. Subsequent to the initial issue of SB 54-44, a deviating strut has been found on an aircraft outside the affected serial number range, and it has been established that some of these struts may have been installed during manufacture. Revision 1 expands the effectivity accordingly.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is an amendment (Amdt 1) that expands the original directive's scope to cover additional aircraft. The original AD applied to a narrower serial number range; Revision 1 of the referenced Service Bulletin (and thus this amendment) adds coverage after a deviating strut was found on an aircraft outside the originally affected range. However, this is a routine safety expansion within the original purpose (preventing engine separation due to faulty struts), not mission creep beyond the directive's intent."},"complexity_factors":["Very short document (under 300 words)","Only 3 defined elements: applicability by serial number, compliance deadlines, and reference to external technical document (Fokker Service Bulletin)","No nested conditional logic or cross-references to other legislation","Single straightforward requirement with two simple exceptions (Note 1 and Note 2)","Technical content is delegated entirely to the referenced Service Bulletin — the AD itself contains no procedural detail"],"plain_english_summary":"This safety directive orders operators of certain Fokker F27 turboprops to inspect and, if necessary, replace upper engine-to-wing brace struts after a pre‑production strut (part 1107‑196‑401) failed and could have caused an engine separation. Affected aircraft are specific serial-numbered F27s; operators must follow Fokker Service Bulletin F27/54‑44 Rev. 1 (previously completed inspections under the original bulletin are acceptable). The inspections prevent catastrophic engine loss and potential loss of control."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Revision 1 expanded the AD's effectivity to include additional aircraft outside the original serial-number range because deviating/pre-production struts were found; Note 1 preserves that aircraft already inspected under the initial service bulletin do not require additional inspection."},"complexity_factors":["Multiple serial-number ranges with different compliance dates (two deadlines).","Mandates action by reference to an external document (Fokker Service Bulletin F27/54-44 Revision 1).","Notes that prior inspections under the initial bulletin exempt aircraft from reinspection, adding an administrative check.","Effectivity was expanded after discovery of deviating/pre-production struts, creating retrospective scope issues.","Safety-critical consequence (potential engine separation) increases enforcement and operational urgency.","Short, fixed compliance timeframe raises scheduling and maintenance planning pressure for operators."],"plain_english_summary":"Requires operators of specified Fokker F27 aeroplanes to inspect and, if necessary, remedy the upper engine nacelle brace struts in accordance with Fokker Service Bulletin F27/54-44 Revision 1, with defined compliance dates (serials 10102–10307 by 31 May 1989; other affected serials by 31 July 1989). The directive responds to a pre-production strut failure that could permit engine separation; Revision 1 expands which aircraft are affected because deviating/pre-production struts were found installed during manufacture. Operators pay inspection and repair costs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f27-117-amdt-1-engine-nacelles-upper-brace-struts","history":"/api/acts/ad-f27-117-amdt-1-engine-nacelles-upper-brace-struts/history","analysis":"/api/acts/ad-f27-117-amdt-1-engine-nacelles-upper-brace-struts/analysis","conflicts":"/api/acts/ad-f27-117-amdt-1-engine-nacelles-upper-brace-struts/conflicts","importantCases":"/api/acts/ad-f27-117-amdt-1-engine-nacelles-upper-brace-struts/important-cases","documents":"/api/acts/ad-f27-117-amdt-1-engine-nacelles-upper-brace-struts/documents"}}