{"id":"F2006B08658","name":"AD/COOL/1 - Stewart Warner Oil Coolers - Inspection and Replacement","slug":"ad-cool-1-stewart-warner-oil-coolers-inspection-and-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51749,"registerId":"commonwealth-F2006B08658-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/COOL/1 - Stewart Warner Oil Coolers - Inspection and Replacement","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nCoolers\n\nAD/COOL/1 Stewart Warner Oil Coolers \\- Inspection NK\n\nand Replacement\n\nApplicability: Stewart Warner oil coolers:\n\nModel 8406J with S/Nos. 101 to 1500 10599A with S/Nos. 101 to 700\n\n10568B with S/Nos. 101 to 579\n\n10578B with S/Nos. 101 to 634\n\nRequirement: Inspect the engine oil cooler for applicability within the affected model and serial number range.\n\nAny affected cooler shall be retired from service and replaced with a serviceable cooler not of the subject serial numbered range.\n\nNote: The oil coolers are fitted to, but not necessarily limited to, the following aircraft:\n\n    1976 and 1977 Model Cessna 172 and 177.\n\n    2. 1976 Model Cessna 177RG.\n\n    3. Consolidated Aeronautics Lake LA-4-200.\n\n    4. Grumman American Model AA-5A and AA-5B.\n\n    5. Mooney M20 Series.\n\nCompliance: Within 100 hours time in service after 30 November 1976.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text is a self-contained airworthiness directive specifying applicability by model and serial number ranges, the mandatory action (retire and replace), affected aircraft examples, and a compliance timeframe. The document does not indicate any change from an earlier or original scope within its own text."},"complexity_factors":["Multiple specific model numbers and distinct serial-number ranges to check (Applicability)","Mandatory retire-and-replace action rather than optional inspection-only (Requirement)","Constraint on acceptable replacement parts — replacements must not be from the subject serial-number ranges (Requirement)","Fixed compliance window tied to flight hours after a calendar date (Compliance)","Potential for parts to be fitted across multiple aircraft types and possibly hard-to-access locations (Note; Applicability)","No alternative compliance procedures or exemptions included in the text (Requirement)"],"plain_english_summary":"This airworthiness directive requires operators to inspect certain Stewart Warner engine oil coolers and, if they fall within specified model/serial-number ranges, remove and replace them with serviceable coolers outside those ranges. \n\nIt affects aircraft owners, operators and maintenance providers that use the listed Stewart Warner coolers; compliance (inspection and replacement at the operator’s expense) is mandatory within the AD’s stated time window to maintain airworthiness."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive focused specifically on defective Stewart Warner oil coolers. It has not expanded beyond its original purpose of removing unsafe equipment from service."},"complexity_factors":["Very short document (under 300 words)","Only 4 defined model/serial number combinations to identify","Single, unambiguous compliance action (inspect and replace)","No cross-references to other legislation or regulations beyond the enabling authority (Civil Aviation Regulations 1998, Part 39)","Clear, fixed compliance deadline with simple calculation (100 hours time in service after specified date)","No conditional logic, exceptions, or alternative compliance methods"],"plain_english_summary":"This is an **Airworthiness Directive** (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of specific aircraft to **inspect and replace certain Stewart Warner oil coolers** that have been identified as defective or unsafe.\n\n**What it does:**\n- Targets three specific models of Stewart Warner oil coolers with particular serial numbers (Model 8406J, 10599A, 10568B, and 10578B within specific serial number ranges)\n- Requires aircraft owners to check if their plane has one of these coolers\n- Mandates that any affected cooler must be **permanently removed from service** and replaced with a safe alternative\n\n**Who it affects:**\n- Owners and operators of aircraft fitted with these specific oil coolers, including:\n  - 1976–1977 Cessna 172 and 177 models\n  - 1976 Cessna 177RG\n  - Consolidated Aeronautics Lake LA-4-200\n  - Grumman American AA-5A and AA-5B\n  - Mooney M20 series aircraft\n\n**Why it matters:**\nOil coolers prevent aircraft engines from overheating. A faulty cooler could cause **engine failure in flight**, posing serious safety risks. This directive forces immediate action to prevent accidents.\n\n**Deadline:**\nAircraft owners had to complete this inspection and replacement within **100 hours of flight time** after 30 November 1976."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cool-1-stewart-warner-oil-coolers-inspection-and-replacement","history":"/api/acts/ad-cool-1-stewart-warner-oil-coolers-inspection-and-replacement/history","analysis":"/api/acts/ad-cool-1-stewart-warner-oil-coolers-inspection-and-replacement/analysis","conflicts":"/api/acts/ad-cool-1-stewart-warner-oil-coolers-inspection-and-replacement/conflicts","importantCases":"/api/acts/ad-cool-1-stewart-warner-oil-coolers-inspection-and-replacement/important-cases","documents":"/api/acts/ad-cool-1-stewart-warner-oil-coolers-inspection-and-replacement/documents"}}