{"id":"F2006B04991","name":"AD/CESSNA 170/62 - Aeroquip Engine Exhaust Mufflers","slug":"ad-cessna-170-62-aeroquip-engine-exhaust-mufflers","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44888,"registerId":"commonwealth-F2006B04991-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 170/62 - Aeroquip Engine Exhaust Mufflers","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 170/62 Aeroquip Engine Exhaust Mufflers 7/98 DM\n\nApplicability: Cessna 172R aeroplanes as detailed by serial number in Cessna Single Engine Service Bulletin SB98-78-01.\n\nRequirement: In accordance with the procedures detailed in Cessna Single Engine Service Bulletin SB98-78-01:\n\n1: Inspect the engine exhaust muffler, and if applicable: 2: de-activate the cabin heating system, and\n\n3: install a placard, and\n\n4: replace the engine exhaust muffler.\n\nNote: FAA Airworthiness Directive 98-02-05 refers.\n\nCompliance: Effective 6 May 1998:\n\n1: Before further flight. 2: Before further flight. 3: Before further flight.\n\n4: Within 50 hours time in service from the effective date of this directive. This airworthiness directive becomes effective on 6 May 1998.\n\nBackground: This directive has been issued to require an inspection of the engine exhaust muffler, and if applicable, action to ensure a defective muffler does not result in carbon monoxide contamination of the aircraft heating system or the aircraft cabin. The requirement follows advice that certain mufflers produced by Aeroquip may have inadequate or failed welded joints.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope: addressing a specific manufacturing defect in Aeroquip exhaust mufflers on specific Cessna 172R aircraft. It has not expanded beyond this safety-critical defect remediation purpose."},"complexity_factors":["Single, specific aircraft model and serial number range","Only 4 numbered requirements with clear conditional logic ('if applicable')","Single cross-reference to a Cessna Service Bulletin and an FAA directive","No defined terms section — uses plain technical language","Simple compliance timeline: immediate for safety-critical items, 50 hours for replacement","Total length: approximately 200 words"],"plain_english_summary":"This Airworthiness Directive orders owners/operators of certain Cessna 172R (per Cessna SB98-78-01 serials) to inspect Aeroquip engine mufflers because cracked welds can leak carbon monoxide into the cabin. \n\nIf defects are found, the heating system must be turned off, a warning placard fitted, and the muffler replaced within 50 flight hours. Inspections and any immediate safety actions must be completed before the aircraft next flies."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive's scope matches its stated safety objective: inspect and, if necessary, disable heating, placard and replace defective Aeroquip mufflers on specified Cessna 172R aircraft to prevent carbon monoxide ingress. It is narrowly targeted by serial number, tied to the manufacturer service bulletin for procedures, and does not expand beyond those specified corrective actions and timelines."},"complexity_factors":["Narrow and specific applicability: limited to Cessna 172R serial numbers listed in Cessna SB98‑78‑01 (Applicability).","Procedural reliance on an external manufacturer document: actions required 'in accordance with' Cessna SB98‑78‑01 (Requirement).","Multiple discrete mandatory actions with different timings (inspect; deactivate heater; install placard; replace muffler) (Requirement).","Short, prescriptive compliance windows: three actions 'before further flight' and replacement 'within 50 hours time in service' (Compliance).","Operator cost and operational impact: parts, labour and potential downtime are imposed on owners/operators (Compliance; Background).","Cross-reference to FAA AD 98‑02‑05 creates reliance on foreign regulator findings (Note).","Low administrative discretion: the directive prescribes specific remedial steps and timelines rather than discretionary standards (Requirement; Compliance)."],"plain_english_summary":"This directive requires owners/operators of certain Cessna 172R aeroplanes (serial numbers listed in Cessna SB98‑78‑01) to inspect Aeroquip engine exhaust mufflers and, where defects are found, deactivate the cabin heater, fit a warning placard and replace the muffler within set time limits. The stated purpose is to prevent carbon monoxide entering the cabin after reports of failed welded joints. Compliance is mandatory and creates immediate inspection, grounding‑risk and replacement costs for affected operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-170-62-aeroquip-engine-exhaust-mufflers","history":"/api/acts/ad-cessna-170-62-aeroquip-engine-exhaust-mufflers/history","analysis":"/api/acts/ad-cessna-170-62-aeroquip-engine-exhaust-mufflers/analysis","conflicts":"/api/acts/ad-cessna-170-62-aeroquip-engine-exhaust-mufflers/conflicts","importantCases":"/api/acts/ad-cessna-170-62-aeroquip-engine-exhaust-mufflers/important-cases","documents":"/api/acts/ad-cessna-170-62-aeroquip-engine-exhaust-mufflers/documents"}}