{"id":"F2006B05069","name":"AD/CESSNA 180/56 Amdt 1 - Vented Fuel Caps","slug":"ad-cessna-180-56-amdt-1-vented-fuel-caps","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44979,"registerId":"commonwealth-F2006B05069-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 180/56 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 180, 182 and Wren 460 Series Aeroplanes\n\nAD/CESSNA 180/56\n\nAmdt 1\n\n  \nVented Fuel Caps 8/80\n\nApplicability: Model 180 with S/Nos. 604, 624, 645, 30000 to 32999, 50001 to 50911 and\n\n18050912 to 18052202. Model 182 with S/Nos. 613, 631, 634, 33000 to 34999,\n\n51001 to 53007 and 18253008 to 18260638.\n\nRequirement: Install vented fuel cap(s) in accordance with Cessna SL No. SE77-6.\n\nNote 1: FAA AD 79-10-14, Amendment 39-3475 refers.\n\nNote 2: 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.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a narrow, targeted safety directive focused on a specific mechanical defect in specific aircraft models. The amendment merely clarifies compliance requirements (prohibiting placards as an alternative) without expanding the scope beyond the original fuel venting safety issue."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined applicability criteria (serial number ranges for two aircraft models)","Single straightforward requirement with one specific technical reference (Cessna SL No. SE77-6)","Simple compliance deadline structure (100 hours TIS after fixed date OR before fixed date)","No nested exceptions or conditional logic — only one explicit prohibition (no placards)","Minimal cross-referencing (one FAA AD reference and one Cessna service letter)"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) requiring specific repairs or modifications to aircraft.\n\n**What it does:** Orders owners and operators of certain Cessna 180, 182, and Wren 460 aeroplanes to replace their standard fuel caps with **vented fuel caps** (caps that allow air to flow in and out of the fuel tank).\n\n**Why it matters:** The original fuel system design had a flaw. If the primary fuel tank vent became blocked or the vent valve stuck, a vacuum could form in the tank, starving the engine of fuel and potentially causing engine failure. The vented caps provide a **backup (secondary) venting system** to prevent this dangerous scenario.\n\n**Who must comply:**\n- **Cessna 180 owners:** Specific serial numbers listed (including early production and two later batches)\n- **Cessna 182 owners:** Specific serial numbers listed (similar pattern of early and later production)\n- **Wren 460 series:** Mentioned in the title but serial numbers not explicitly detailed in this excerpt\n\n**The requirement:** Install vented fuel caps following Cessna Service Letter SE77-6. Importantly, you **cannot** just put a warning sticker (placard) on the aircraft instead — that shortcut is specifically banned.\n\n**When:** The deadline has long passed — within 100 flight hours after 31 August 1979 or before 1 January 1980, whichever came later.\n\n**The backstory:** This is actually an **amendment** (Amendment 1) to an earlier directive. Some people had tried to comply by fitting placards instead of the proper caps, so CASA added a note to close that loophole."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The Directive has been clarified to disallow use of a placard as an alternative to installing vented fuel caps (Note 2). That addition narrows acceptable compliance options and removes a previously misinterpreted alternative, while leaving the affected models/serial-number ranges and the stated compliance timeline unchanged (Applicability; Requirement; Compliance; Background)."},"complexity_factors":["Applicability defined by detailed serial-number ranges across multiple models, requiring careful aircraft identification (Applicability).","Mandatory method of compliance: installation must follow Cessna SL No. SE77-6, creating a technical conformity requirement (Requirement).","Explicit prohibition of an alternative compliance measure — fitting a placard is not acceptable — which narrows remedy options and requires physical modification (Note 2).","Compliance deadline uses a compound trigger ('within 100 hours after 31 Aug 1979 or before 1 Jan 1980, whichever is later'), imposing recordkeeping and calculation duties on operators (Compliance).","Reference to an external FAA AD (79-10-14) links this directive to foreign regulatory material, potentially requiring cross-reference checks (Note 1).","Who bears costs and action: aircraft owners/operators must purchase and fit parts and arrange installation, creating direct financial and scheduling burdens (Requirement; Compliance).","Background states change arose from misinterpretation and adds a clarifying NOTE, indicating implementation and interpretation risk requiring clearer oversight (Background)."],"plain_english_summary":"Requires installation of vented fuel caps on specified Cessna 180, 182 and Wren 460 series aircraft (listed serial numbers), fitted in accordance with Cessna SL No. SE77-6. A placard is explicitly not an acceptable alternative. The directive adds secondary venting to guard against obstructed primary vents or sticking tank vent valves; owners/operators must fit the caps within 100 hours' time-in-service after 31 August 1979 or before 1 January 1980, whichever is later."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-180-56-amdt-1-vented-fuel-caps","history":"/api/acts/ad-cessna-180-56-amdt-1-vented-fuel-caps/history","analysis":"/api/acts/ad-cessna-180-56-amdt-1-vented-fuel-caps/analysis","conflicts":"/api/acts/ad-cessna-180-56-amdt-1-vented-fuel-caps/conflicts","importantCases":"/api/acts/ad-cessna-180-56-amdt-1-vented-fuel-caps/important-cases","documents":"/api/acts/ad-cessna-180-56-amdt-1-vented-fuel-caps/documents"}}