{"id":"F2006B02317","name":"AD/ALF/3 - Compressor Housing Support Assembly 2-103-070-07 - Inspection and Replacement","slug":"ad-alf-3-compressor-housing-support-assembly-2-103-070-07-inspection-and-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41547,"registerId":"commonwealth-F2006B02317-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ALF/3 - Compressor Housing Support Assembly 2-103-070-07 - Inspection and Replacement","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAlliedSignal (Lycoming) Turbine Engines \\- ALF502 and LF507 Series\n\nAD/ALF/3 Compressor Housing Support Assembly 2-103-070-07 \\- Inspection and Replacement\n\n  \n1/86\n\nApplicability: Lycoming model ALF 502L-2 turbofan engine S/Nos. LF03020, LF03021, LF03038, LF03039.\n\nDocument: 1. Lycoming SB No. ALF 502-72-0014; or\n\n2. AD/LYC-T/20.\n\nCompliance: 1. Immediately upon receipt of this Directive and after each 100 hours of engine operation thereafter until affected support assemblies are replaced.\n\n2. Affected compressor housing support assemblies must be replaced not later than 800 hours or 600 cycles time in service whichever occurs first.\n\nBackground: This Directive is issued as the result of notification from the engine manufacturer that the affected engines were installed with the rear engine mount improperly assembled. With this condition, normal flight loads may have imposed excessive stress on the compressor housing support assembly engine mounting lugs. Affected mounting lugs must be periodically inspected for possible cracks until compressor housing support assembly is replaced.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Scope aligns with the stated purpose: it targets specific serial-numbered ALF502L-2 engines identified as improperly assembled and prescribes inspections and a required replacement window. The directive implements the manufacturer's notification without expanding applicability or altering mandated intervals. (Background; Applicability; Compliance.)"},"complexity_factors":["Narrow applicability to a small set of engine serial numbers (Applicability)","Clear, short compliance schedule: immediate, then every 100 hours until replacement (Compliance)","Definite replacement deadline expressed in hours or cycles (800 hours or 600 cycles) (Compliance)","Inspections and replacement reference manufacturer service bulletin or prior AD (Document), requiring technical procedures and parts","Enforcement under Civil Aviation Regulations Part 39 framework (header), requiring record-keeping and operator compliance"],"plain_english_summary":"This airworthiness directive requires immediate and recurring inspections of compressor housing support assembly 2-103-070-07 on specified Lycoming ALF502L-2 engines and mandates replacement of affected assemblies within 800 hours or 600 cycles. (Applicability; Compliance.)\n\nIt affects owners/operators of the listed serial-numbered engines, who must inspect on receipt and every 100 engine hours until replacement and bear inspection and replacement costs while tracking hours/cycles. (Background; Compliance.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific manufacturing defect in four identified engines. It has not expanded beyond its original purpose of mandating inspection and replacement of a defective compressor housing support assembly."},"complexity_factors":["Very short document (under 300 words)","Only 4 specific engine serial numbers affected (narrow applicability)","Simple two-part compliance requirement (inspect now/repeat, then replace by deadline)","No defined terms section — uses plain technical language","No cross-references to other legislation beyond citing the source service bulletin and superseded directive","Single background explanation with clear causal chain"],"plain_english_summary":"This CASA Airworthiness Directive orders immediate and recurring inspections of the compressor housing support assembly, then mandatory replacement of that assembly within 800 flight hours or 600 flight cycles, for four specific Lycoming ALF 502L-2 engines (serials LF03020, LF03021, LF03038, LF03039).  \n\nIt targets operators of aircraft using those engines (e.g., BAe 125 series) because an assembly misfit can crack mounting lugs, risking engine failure or separation."}},"importantCases":[],"_links":{"self":"/api/acts/ad-alf-3-compressor-housing-support-assembly-2-103-070-07-inspection-and-replacement","history":"/api/acts/ad-alf-3-compressor-housing-support-assembly-2-103-070-07-inspection-and-replacement/history","analysis":"/api/acts/ad-alf-3-compressor-housing-support-assembly-2-103-070-07-inspection-and-replacement/analysis","conflicts":"/api/acts/ad-alf-3-compressor-housing-support-assembly-2-103-070-07-inspection-and-replacement/conflicts","importantCases":"/api/acts/ad-alf-3-compressor-housing-support-assembly-2-103-070-07-inspection-and-replacement/important-cases","documents":"/api/acts/ad-alf-3-compressor-housing-support-assembly-2-103-070-07-inspection-and-replacement/documents"}}