{"id":"F2006B05231","name":"AD/CESSNA 206/27 Amdt 1 - Vented Fuel Caps","slug":"ad-cessna-206-27-amdt-1-vented-fuel-caps","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":45512,"registerId":"commonwealth-F2006B05231-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 206/27 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 206 Series Aeroplanes\n\nAD/CESSNA 206/27\n\nAmdt 1\n\n  \nVented Fuel Caps 8/80\n\nApplicability: Model 206 with S/Nos. 206-0001 to 206-0275.\n\nModel U206 and TU206 with S/Nos. U206-0276 to U206-1444 and U20601445 to U20601666.\n\nModel P206 and TP206 with S/Nos. P206-0001 to P206-0603 and P20600604 to P20600647.\n\nRequirement: Install vented fuel cap(s) in accordance with Cessna SL No. SE77-6.\n\nNote: FAA AD 79-10-14, Amendment 39-3475 refers.\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.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"The amendment clarifies and narrows acceptable compliance by adding a note that fitting a placard is not an acceptable alternative to installing vented fuel caps. The underlying requirement for secondary venting remains the same, but the change removes a previously used alternative and thus increases the practical compliance burden for operators who might otherwise have used a placard."},"complexity_factors":["Single, specific technical mandate: install vented fuel caps per Cessna SL No. SE77-6 (clear operational requirement)","Narrow applicability limited to explicit serial‑number ranges for Model 206, U206/TU206 and P206/TP206 (reduces scope complexity)","Reference to an external document (Cessna SL SE77-6) requires operators to consult and follow another source for installation details","Express prohibition on placard alternative removes a potential lower‑cost compliance option and creates a binary compliance decision","Fixed compliance window tied to historical dates (within 100 hours after 31 Aug 1979 or before 1 Jan 1980), which is administratively simple but time‑sensitive","Cross-reference to FAA AD 79-10-14 (Amendment 39-3475) creates an additional external reference point","Compliance enforcement and cost allocation fall on owners/operators (arrange and pay for parts/labour)","Background note (added due to misinterpretation) clarifies intent but indicates prior ambiguity in acceptable compliance methods"],"plain_english_summary":"Requires owners/operators of specified Cessna 206-series aeroplanes to install vented fuel caps in accordance with Cessna Service Letter SE77-6; fitting a placard is expressly not an acceptable substitute. Compliance is due within 100 hours time‑in‑service after 31 August 1979 or before 1 January 1980, whichever is later. The stated purpose is to provide secondary venting to guard against obstructed primary vents or sticking vent valves. Owners/operators must arrange and pay for the installation and meet the time deadline."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is Amendment 1 to an existing AD. The amendment adds only a clarifying note that placards are not acceptable alternatives. The scope remains tightly focused on the original safety issue (fuel tank venting) and has not expanded beyond the specific aircraft models originally targeted."},"complexity_factors":["Single, specific mechanical requirement (install vented caps)","Only 3 defined model/serial number ranges to check for applicability","One cross-reference to Cessna Service Letter and one FAA AD for background","Simple compliance deadline with clear 'whichever is later' logic","No nested exceptions or conditional sub-requirements","Total length: approximately 200 words"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety order for aircraft owners and operators.\n\n**What it does:** Requires owners of specific Cessna 206 series aircraft to replace their standard fuel caps with **vented fuel caps**. These special caps allow air to enter the fuel tank if the main vent system gets blocked.\n\n**Why it matters:** If a fuel tank can't vent properly, a vacuum can form as fuel is used. This can cause engine fuel starvation (the engine stops getting fuel even when there's plenty in the tank), potentially leading to engine failure and crash.\n\n**Who must comply:** Owners of specific Cessna 206 models with serial numbers listed in the document — roughly early production aircraft from the 1960s-1970s era.\n\n**The specific requirement:** Install vented caps following Cessna's Service Letter SE77-6. Importantly, you **cannot** just put up a warning sign (placard) instead — the caps must actually be installed.\n\n**When it had to be done:** Within 100 flight hours after 31 August 1979, or before 1 January 1980 — whichever gave more time."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-206-27-amdt-1-vented-fuel-caps","history":"/api/acts/ad-cessna-206-27-amdt-1-vented-fuel-caps/history","analysis":"/api/acts/ad-cessna-206-27-amdt-1-vented-fuel-caps/analysis","conflicts":"/api/acts/ad-cessna-206-27-amdt-1-vented-fuel-caps/conflicts","importantCases":"/api/acts/ad-cessna-206-27-amdt-1-vented-fuel-caps/important-cases","documents":"/api/acts/ad-cessna-206-27-amdt-1-vented-fuel-caps/documents"}}