{"id":"F2006B04964","name":"AD/CESSNA 170/32 Amdt 1 - Vented Fuel Caps","slug":"ad-cessna-170-32-amdt-1-vented-fuel-caps","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44840,"registerId":"commonwealth-F2006B04964-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 170/32 Amdt 1 - Vented Fuel Caps","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)  \nCessna 170, 172, F172, FR172 and 175 Series Aeroplanes\n\nAD/CESSNA 170/32\n\nAmdt 1\n\n  \nVented Fuel Caps 8/80\n\nApplicability: Model 170 with S/Nos. 609 and 18729 to 27169.\n\nModel 172 with S/Nos. 610, 612, 615, 622, 625, 630, 638, 28000 to 29999, 36000 to\n\n36999, 46001 to 47746 and 17247747 to 17265684.\n\nModel P172 with S/Nos P17257120 to P17257188.\n\nModel R172 with S/Nos. P17227189 and R1720001 to R1720617.\n\nModel 175 with S/Nos. 619, 28700A, 55001to 56777 and 17556778 to 17557119.\n\nRequirement: Install vented fuel cap(s) in accordance with:\n\n1. Cessna SL No. SE 77-6; or\n\n2. FAA AD 79-10-14, Amendment 39-3475; or\n\n3. Bureau Veritas AD 79-155-IMP(A).\n\nNote: Installation of a placard is not an acceptable alternative to installation of vented fuel caps.\n\nCompliance: Within 100 hours time in service after 31 August 1979 or before 1 January 1980 whichever is the later.\n\nBackground: To guard against the possibility of either an obstructed primary vent or sticking of the fuel tank vent valve it has been found necessary to provide secondary venting in the form of vented fuel caps. Due to some misinterpretation of this Directive a NOTE has now been added to disallow the fitting of a placard.\n\nFederal Register of Legislative Instruments F2006B04964","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is Amendment 1 to an existing Airworthiness Directive. The amendment is narrow and specific — it adds a note clarifying that placards are not an acceptable alternative to vented fuel caps. This does not expand the scope beyond the original safety purpose (ensuring proper fuel tank venting); it merely tightens compliance to prevent misinterpretation."},"complexity_factors":["Very short document (approximately 250 words)","Only 3 defined applicability categories (model, serial number ranges, compliance deadline)","Simple binary requirement: install vented caps, no alternatives permitted","Single cross-reference to three alternative technical standards (Cessna SL, FAA AD, Bureau Veritas AD)","No nested conditions or exceptions beyond the serial number applicability","Clear, unambiguous compliance deadline with simple 'whichever is later' logic"],"plain_english_summary":"This CASA Airworthiness Directive mandates that owners/operators of specified Cessna 170/172/F172/FR172/175 aeroplanes install vented fuel caps to prevent fuel-tank pressure or vacuum conditions that can cause engine fuel starvation. Placards alone are explicitly not acceptable.\n\nAffected aircraft (listed by serial number) were required to comply within 100 flight hours after 31 August 1979 or before 1 January 1980, using one of three approved technical documents from Cessna, the FAA, or Bureau Veritas."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The instrument clarifies and narrows acceptable compliance methods by adding a NOTE disallowing use of a placard as an alternative; the background states this NOTE was added to address prior misinterpretation, thereby tightening scope compared with the prior, broader practice."},"complexity_factors":["Applicability tied to multiple specific serial-number ranges (adds administrative tracking).","Requirement cross-references three external documents (Cessna SL, FAA AD, Bureau Veritas AD) — increases interpretive and evidentiary complexity.","Compliance timing uses a compound trigger (100 flight hours after a fixed date or before another fixed date — ‘whichever is the later’).","Explicit prohibition of a placard alternative narrows previously ambiguous compliance options.","Technical installation (must follow prescribed service/AD procedures) creates a technical compliance burden on maintenance providers and owners.","Enforcement and proof of compliance rest with operators and maintenance organisations (costs of parts, labour, record-keeping)."],"plain_english_summary":"This airworthiness directive requires owners/operators of specified Cessna 170/172/P172/R172/175 aeroplanes (listed by serial number) to install vented fuel caps using one of three prescribed technical instructions (a Cessna service letter, an FAA AD, or a Bureau Veritas AD). It explicitly forbids using a placard instead. Owners/operators pay for parts and installation and must comply within 100 flight hours after 31 August 1979 or by 1 January 1980 (whichever is later). The regulator prescribes the acceptable methods, creating a narrow, mandatory compliance obligation."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-170-32-amdt-1-vented-fuel-caps","history":"/api/acts/ad-cessna-170-32-amdt-1-vented-fuel-caps/history","analysis":"/api/acts/ad-cessna-170-32-amdt-1-vented-fuel-caps/analysis","conflicts":"/api/acts/ad-cessna-170-32-amdt-1-vented-fuel-caps/conflicts","importantCases":"/api/acts/ad-cessna-170-32-amdt-1-vented-fuel-caps/important-cases","documents":"/api/acts/ad-cessna-170-32-amdt-1-vented-fuel-caps/documents"}}