{"id":"F2006B09712","name":"AD/F27/145 - Engine Nacelle Fuel Line Inspection","slug":"ad-f27-145-engine-nacelle-fuel-line-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115885,"registerId":"commonwealth-F2006B09712-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F27/145 - Engine Nacelle Fuel Line Inspection","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/F27/145 Engine Nacelle Fuel Line Inspection 1/98\n\nApplicability: All Model Fokker F27 Mk100 through Mk 700 series aeroplanes, all serial numbers.\n\nRequirement: 1. Inspect the forward fuel feed lines P/N F471-27-1 or P/N F252-27-1 (RH Nacelle) and P/N F470-27-1 or P/N F152-27-1 (LH Nacelle), located at frame STA.3038, for damage in accordance with Part 1 of the Accomplishment Instructions of Fokker Service Bulletin (SB) F27/28-62 dated September 1, 1997 or a later RLD approved revision. If damage is found proceed with paragraph (2) of these requirements. If no damage is found proceed with paragraph (3) of these requirements.\n\n    2. If any fuel line is found to be damaged, accomplish one of the following:\n\n    (a) If the depth of the damage exceeds 0.009 inch, replace the affected fuel line with an airworthy part of the same part number.\n\n    (b) If the depth of the damage is less than 0.009inch, re-inspect the affected fuel line at every daily inspection thereafter and replace the affected fuel line with an airworthy part of the same part number within the next 50 flight hours following detection.\n\n    3. Modify the routing and support of the High Tension leads of the Inboard Ignition units in accordance with Part 2 of the Accomplishment Instructions of Fokker SB F27/28-62 dated September 1, 1997 or a later RLD-approved revision.\n\nNote: RLD BLA 1997-094(A) dated September 1997 refers.\n\nCompliance: 1. Within six months of the effective date of this directive.\n\n    2. (a) Before Next Flight.\n\n(b) Inspect at every daily inspection and replace within 50 flight hours of discovery.\n\n    3. Within six months of the effective date of this directive.\n\nThis airworthiness directive becomes effective on 1 January 1998.\n\nBackground: An operator reported a fuel leak which was found to originate from a hole in the forward fuel feed line, Part No. F471-27-1, located at nacelle frame STA.3038. The damage to the pipe was found to be caused by interference between the nearby Ignition Unit High Tension leads and the fuel feed line. At least one of the ignition leads appeared to be incorrectly supported, resulting in chafing and damage to the fuel feed line. If uncorrected this condition could lead to significant loss of fuel and/or nacelle fire. This directive introduces an inspection of the fuel feed lines, replacement of damaged fuel feed components and re-routing of the affected high tension leads.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating inspection and repair of fuel line chafing issues."},"complexity_factors":["Single, specific technical task with clear sequential steps","Only 4 defined part numbers and one technical reference (Fokker Service Bulletin)","Simple conditional logic: damage found vs. no damage found, with depth threshold of 0.009 inch","No nested exceptions or cross-references to other legislation","Self-contained document with explicit compliance deadlines","Technical but not legally complex — written for aircraft engineers rather than lawyers"],"plain_english_summary":"This CASA Airworthiness Directive orders inspections, repairs, and ignition‑cable rerouting on all Fokker F27 Mk100–Mk700 aircraft to stop ignition leads rubbing fuel lines, which can cause fuel leaks and engine fires. \n\nOperators must inspect specified fuel lines, replace any deep damage before flight, monitor shallow damage daily and replace within 50 flight hours, and reroute ignition cables. Inspections and rerouting were required within six months of 1 January 1998."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive confines action to the specified forward fuel feed lines and the routing/support of ignition High Tension leads on the listed F27 models, directly addressing the reported chafing and fuel leak. It does not broaden to other components, systems or aircraft types and thus aligns with the stated Background and Applicability (Background; Applicability; Requirement)."},"complexity_factors":["Clear, prescriptive inspection and removal thresholds (damage depth 0.009 inch) require precise measurement and judgment (Requirement 2(a)/(b)).","Tiered remedial actions create operational sequencing: immediate replacement if depth exceeds threshold; repeated daily inspections and replacement within 50 flight hours if below threshold (Requirement 2(a)/(b); Compliance).","Routing and support modification of High Tension leads must follow manufacturer Service Bulletin Part 2 or later RLD-approved revision, requiring access to and implementation of external technical instructions (Requirement 3; Requirement 1).","Applicability to all serial numbers across multiple Mk100–Mk700 models increases coordination and fleet-wide logistics for operators and maintenance organisations (Applicability).","Mandated compliance windows including 'before next flight' and 'within six months' produce scheduling and potential aircraft downtime impacts (Compliance).","Dependence on regulator- or manufacturer-approved revisions (RLD/Fokker SB) introduces procedural reliance on external approvals and potential delay or variation in acceptable methods (Requirement 1; Note)."],"plain_english_summary":"This airworthiness directive requires operators of all Fokker F27 Mk100–Mk700 aeroplanes to inspect specified forward fuel feed lines at nacelle frame STA.3038, repair or replace any damaged lines, and reroute/support ignition high-tension leads. It affects aircraft owners, operators and maintenance organisations and sets mandatory timing (including some actions before next flight) because a reported chafing of ignition leads caused a fuel leak that could lead to fuel loss or a nacelle fire."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f27-145-engine-nacelle-fuel-line-inspection","history":"/api/acts/ad-f27-145-engine-nacelle-fuel-line-inspection/history","analysis":"/api/acts/ad-f27-145-engine-nacelle-fuel-line-inspection/analysis","conflicts":"/api/acts/ad-f27-145-engine-nacelle-fuel-line-inspection/conflicts","importantCases":"/api/acts/ad-f27-145-engine-nacelle-fuel-line-inspection/important-cases","documents":"/api/acts/ad-f27-145-engine-nacelle-fuel-line-inspection/documents"}}