{"id":"F2006B05119","name":"AD/CESSNA 185/28 - Goodyear Fuel Cells","slug":"ad-cessna-185-28-goodyear-fuel-cells","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":45132,"registerId":"commonwealth-F2006B05119-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 185/28 - Goodyear Fuel Cells","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Cessna 185 Series Aeroplanes\n\n \n\nAD/CESSNA 185/28 Goodyear Fuel Cells 6/78\n\nApplicability: All models 185 fitted with Goodyear BTC-39 fuel cells. Requirement:  Action in accordance with Cessna SL No. SE78-10.\n\nCompliance: Within 100 hours time in service after 30 June 1978 and thereafter annually as detailed in Cessna SL No. SE 78-10.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive’s scope is limited to Cessna 185 series aeroplanes fitted with Goodyear BTC-39 fuel cells and requires actions set out in Cessna Service Letter No. SE78-10, to be done within 100 hours after 30 June 1978 and annually thereafter (Applicability, Requirement, Compliance). The text does not indicate any expansion or narrowing of that scope relative to its stated applicability and requirements."},"complexity_factors":["Narrow and specific applicability: only Cessna 185 aircraft with Goodyear BTC-39 fuel cells (Applicability).","Mandatory reference to an external document (Cessna SL No. SE78-10) for detailed work instructions (Requirement).","Fixed and recurring compliance timeline (initial within 100 hours after 30 June 1978; annual thereafter) creates an ongoing administrative/maintenance burden (Compliance).","Concise directive text leaves operational detail to the service letter, reducing ambiguity in the AD but creating dependency on another document (Requirement).","Authority established in Civil Aviation Regulations Part 39 (header) — procedural context adds a regulatory enforcement layer though not detailed in the text."],"plain_english_summary":"Summary\n\n- What this instrument does (mechanically): This entry is an Airworthiness Directive issued under the Commonwealth Civil Aviation Regulations (Part 39, Schedule of Airworthiness Directives). It applies to Cessna 185 series aeroplanes that are fitted with Goodyear BTC-39 fuel cells (Applicability). It requires operators to carry out the work described in Cessna Service Letter No. SE78-10 (Requirement). The first compliance action must be completed within 100 hours time in service after 30 June 1978 and, thereafter, the actions specified in the service letter must be carried out annually (Compliance).\n\n- Who it affects: Owners and operators of Cessna 185 aircraft fitted with Goodyear BTC-39 fuel cells, and maintenance organisations that service those aircraft (Applicability, Requirement, Compliance).\n\n- Why it matters (stated mechanism, then practical implications): The directive mechanically mandates inspection/maintenance or other actions as set out in a specific manufacturer service letter (Requirement). Operators must obtain and follow that service letter and schedule the required work within the stated times (Compliance). Practically, that means operators will allocate time, labour and parts to complete the service-letter work, creating recurring maintenance cost and aircraft downtime.\n\nStated purpose and testing that claim against likely costs and trade-offs\n\n- Stated-purpose claim (as implied by being an Airworthiness Directive): The directive directs specific actions to address an identified airworthiness issue affecting fuel cells by requiring compliance with Cessna SL No. SE78-10 (Requirement). The text itself sets the mandatory action and timing but does not include a narrative explanation of the technical defect or incidents prompting the directive.\n\n- Who pays: Aircraft owners/operators must pay for the work specified in the service letter (Requirement, Compliance). Maintenance organisations will receive work, but the expense of parts, labour and downtime is borne by the operator.\n\n- Incentives and behaviour changes: Operators are incentivised to complete the required work on schedule to meet the regulatory requirement (Compliance). The need to comply may lead operators either to perform the mandated actions or to remove/replace the BTC-39 fuel cells if that is an operational option referenced in the service letter (Requirement).\n\n- Compliance burden and implementation risk: The directive creates a recurring (annual) compliance obligation after an initial action within 100 hours (Compliance). Implementing the directive requires access to and correct application of Cessna SL No. SE78-10 (Requirement). The directive’s brevity means operational detail sits in the service letter, so timely access to and correct interpretation of that external document is an implementation dependency (Requirement).\n\n- Trade-offs and opportunity costs: Time, parts and maintenance capacity must be allocated to meet the schedule, which displaces other maintenance or operational uses of the aircraft. If the required actions involve replacement of fuel cells or grounding for repair, there is additional direct cost and lost operational revenue (Compliance).\n\n- Bureaucratic discretion and enforcement: The directive is issued within the Civil Aviation Regulations Part 39 framework (header). The text itself specifies mandatory action and timing with limited express discretion for variation; any variation or alternative means of compliance would need to be dealt with under the regulatory framework rather than by this text (Requirement, Compliance).\n\n- Effects on private enterprise and competition: Maintenance providers able to perform the service-letter work will have demand for that work (Requirement). The directive imposes costs on aircraft owners/operators that are specific to those fitted with the named fuel cell model (Applicability)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1978 addressing a specific safety defect in a specific aircraft part. It has not expanded beyond its original purpose of ensuring the airworthiness of Goodyear BTC-39 fuel cells in Cessna 185 aircraft."},"complexity_factors":["Extremely short document (under 150 words of substantive content)","Only one defined applicability criterion (Cessna 185 models with Goodyear BTC-39 fuel cells)","Single cross-reference to external technical document (Cessna SL No. SE78-10)","Simple binary compliance structure (initial inspection + recurring annual requirement)","No nested exceptions, conditional logic, or interpretive provisions","No internal definitions section — relies entirely on external aircraft type certificates and manufacturer documentation"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it like a compulsory recall notice, but for aircraft parts.\n\n**What it does:** It requires owners and operators of **Cessna 185 series aeroplanes** to inspect or replace **Goodyear BTC-39 fuel cells** (the rubber bladders inside the fuel tanks). The directive references a specific Cessna Service Letter (SL No. SE78-10) which contains the detailed technical instructions.\n\n**Who it affects:** Anyone who owns, operates, or maintains a Cessna 185 aircraft fitted with these specific Goodyear fuel cells.\n\n**What must be done:**\n- **First inspection:** Within 100 hours of flying time after 30 June 1978\n- **Ongoing checks:** Every year thereafter\n- **How:** Follow the technical steps in Cessna Service Letter SE78-10\n\n**Why it matters:** Fuel cells can degrade, leak, or fail over time. A fuel leak in an aircraft is a serious fire and explosion risk. This directive ensures these specific fuel cells are checked regularly to prevent catastrophic failure.\n\n**Key point:** This is not optional. Compliance is legally mandatory under the Civil Aviation Regulations 1998, Part 39."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-185-28-goodyear-fuel-cells","history":"/api/acts/ad-cessna-185-28-goodyear-fuel-cells/history","analysis":"/api/acts/ad-cessna-185-28-goodyear-fuel-cells/analysis","conflicts":"/api/acts/ad-cessna-185-28-goodyear-fuel-cells/conflicts","importantCases":"/api/acts/ad-cessna-185-28-goodyear-fuel-cells/important-cases","documents":"/api/acts/ad-cessna-185-28-goodyear-fuel-cells/documents"}}