{"id":"F2006B11202","name":"AD/LYC/71 Amdt 1 - Pushrod - Inspection","slug":"ad-lyc-71-amdt-1-pushrod-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56912,"registerId":"commonwealth-F2006B11202-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LYC/71 Amdt 1 - Pushrod - Inspection","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)  \nLycoming Piston Engines\n\nAD/LYC/71\n\nAmdt 1\n\n  \nPushrod \\- Inspection 3/81\n\nApplicability: 0-235 series engines with S/Nos. L-12500-15 to L-20676-15 inclusive, all Lycoming remanufactured 0-235 series engines, regardless of S/No., shipped between 10 December 1976 and 8 November 1979, and all 0-235 series engines regardless of S/No., that had pushrods replaced between 10 December 1976, and 24 November 1980. This AD does not apply to engines incorporating eight pushrods identified by revision letter K or subsequent revision letter, or by Code T-T, \\-85, or the symbol # as described in SB No. 453A.\n\nRequirement: Part 1 - Remove all eight pushrods and inspect for loose ball ends and evidence of bulging and splitting of the pushrod tubing. Measure the length of the pushrod assembly. The overall length shall not be less than 11-17/32 inches. If all these conditions are satisfactory, set valve clearances in accordance with Para. 8 of Lycoming SI Nos. 1388A dated 25 January 1980, and 1068A dated 1 September 1978. If any pushrod is found damaged or is less than the specified dimension noted above, replace with a serviceable part prior to further flight.\n\nPart 2 \\- Measure and record valve tappet clearance in accordance with Lycoming SI Nos. 1388A and 1068A. If any valve clearance increases more than .015 inch since the last 25 hour inspection, remove the pushrod and inspect for damage and shortening in accordance with Item 1 above.\n\nCompliance: Part 1 \\- Within 25 hours time in service after 31 March 1981 or before 14 April 1981, whichever occurs first.\n\nPart 2 \\- Within 25 hours time in service after 31 March 1981 or before 14 April 1981 whichever occurs first and thereafter at intervals not exceeding 25 hours time in service.\n\nNote: Engines complying with the initial issue of this Directive satisfy the requirements of this issue of the Directive.\n\nBackground: This Directive is raised in issue to reflect the following changes:\n\n    (a) Engines of Serial Numbers Listed in Lycoming SB No. 435A as exempt from compliance are now also affected.\n\n    (b) FAA Directive No. 80-25-02, Rev. 2 forms the basis of this Directive. Overseas reports show one recent fatal accident attributable to this problem and in excess of 80 reports of failed pushrods found in service. A number of local defects have also occurred.\n\nInspection of suspect pushrods is therefore necessary to prevent failure.\n\nIt is known that Ansett General Aviation Bankstown have the necessary tooling to inspect pushrods and reidentify as a -85 suffix to the part number.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Scope was expanded from the earlier issue: engines previously listed as exempt in Lycoming SB No. 435A are now included; remanufactured engines shipped between 10 Dec 1976 and 8 Nov 1979 and engines with pushrods replaced between 10 Dec 1976 and 24 Nov 1980 are also captured. Exemptions remain for pushrods identified by revision K (or later) or by specified codes/symbols per SB No. 453A."},"complexity_factors":["Detailed applicability based on serial-number ranges, remanufacture dates and dates of prior pushrod replacement (creates lookup/compliance burden).","Multiple exemptions and identifications (revision letter K or later, Code T-T, -85, or symbol # per SB No. 453A) requiring part-mark verification.","Two-part requirement structure: a one‑off removal/inspection plus ongoing 25‑hour interval tappet clearance checks.","Precise dimensional threshold (overall length 11-17/32 inches) and clearance-change trigger (.015 inch) that demand accurate measurement tools and recordkeeping.","Cross-references to Lycoming Service Instructions (SI Nos. 1388A and 1068A), FAA Directive and Lycoming Service Bulletin, increasing compliance complexity and dependence on external documents.","Tight compliance timeline (within 25 hours time in service after 31 March 1981 or before 14 April 1981 whichever occurs first) creating operational scheduling pressure.","Requirement to remove and replace parts prior to further flight if noncompliant, imposing immediate parts availability and maintenance cost implications.","Note about a specific MRO (Ansett General Aviation Bankstown) having tooling to reidentify parts suggests uneven access to approved tooling/processing across operators."],"plain_english_summary":"This airworthiness directive requires owners/operators of specified Lycoming 0-235 piston engines to remove and inspect all eight pushrods, measure their overall length (must be at least 11-17/32 inches) and check valve tappet clearances, replacing any pushrod that is damaged or undersize. It imposes an immediate compliance window and then recurring 25‑hour checks. Operators pay for inspections and parts; the regulator enforces compliance and refers to Lycoming service instructions for the inspection and adjustment procedures."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"This is Amendment 1 to an existing directive. The scope expanded from the original issue to include engines previously exempted under Lycoming SB No. 435A. The amendment also incorporates updated FAA source material (Rev. 2 of the FAA directive) and reflects additional incident data (the fatal accident and 80+ failure reports) that justified broadening the applicability."},"complexity_factors":["Multiple applicability criteria requiring cross-referencing of serial numbers, manufacturing dates, and service history","Two-part compliance structure with different ongoing obligations (one-time inspection vs. recurring 25-hour checks)","Specific technical measurements requiring specialised tools (11-17/32 inch length, .015 inch clearance tolerance)","Reference to external technical documents (Lycoming Service Bulletins 453A and 435A, Service Instructions 1388A and 1068A) without reproducing their content","Exemption criteria based on part marking codes (revision letter K, Code T-T, -85 suffix, # symbol) requiring visual identification","Nested date ranges for applicability (manufacturing window vs. replacement window)","Amendment structure referencing prior versions and FAA source material"],"plain_english_summary":"This CASA Airworthiness Directive orders owners/operators of certain Lycoming O-235 piston engines (specific serial numbers, remanufactured engines from a 1976–79 window, and engines with pushrods replaced in the affected interval) to inspect and, if necessary, replace all eight engine pushrods. Mechanics must remove, inspect for defects and measure pushrod length, and replace any that fail limits; valve clearances must then be checked every 25 flight hours.\n\nIt responds to one fatal accident and many worldwide pushrod failures to prevent in‑flight engine loss."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-lyc-71-amdt-1-pushrod-inspection","history":"/api/acts/ad-lyc-71-amdt-1-pushrod-inspection/history","analysis":"/api/acts/ad-lyc-71-amdt-1-pushrod-inspection/analysis","conflicts":"/api/acts/ad-lyc-71-amdt-1-pushrod-inspection/conflicts","importantCases":"/api/acts/ad-lyc-71-amdt-1-pushrod-inspection/important-cases","documents":"/api/acts/ad-lyc-71-amdt-1-pushrod-inspection/documents"}}