{"id":"F2006B08296","name":"AD/CESSNA 400/109 - Exhaust System Components - Inspection","slug":"ad-cessna-400-109-exhaust-system-components-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115626,"registerId":"commonwealth-F2006B08296-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 400/109 - Exhaust System Components - Inspection","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 400 Series Aeroplanes\n\nAD/CESSNA 400/109 Exhaust System Components \\- Inspection\n\n  \n1/99 TX\n\nApplicability: Model 414A aeroplanes, serial numbers 1 through 1212 that have had an exhaust system WYE tube changed since 01 May 1998.\n\nRequirement: 1. Establish the part number of the exhaust system WYE tube fitted to the aircraft by search of the aircraft records or by physical examination of the component.\n\n2. Remove and replace exhaust system WYE tubes P/N 9910299-25 or P/N 9910299- 26 with exhaust system WYE tubes P/N 9910299-8 (for P/N 9910299-25) or P/N 9910299-9 (for P/N 9910299-26) or any other WYE tube that is approved by the aircraft manufacturer.\n\nNote: US FAA Priority Letter 98-24-14 dated 13 November 1998 refers.\n\nCompliance: 1. Before further flight after receipt of this Airworthiness Directive.\n\n2. Before further flight if defective components are identified.\n\nThis Airworthiness Directive becomes effective on 20 November 1998.\n\nBackground: The FAA has received reports of five instances where the engine exhaust components in the WYE tube installed on certain Cessna aircraft were manufactured without welds. These nonwelded areas lead to leaks in the exhaust system on the turbocharged engine installations on these aeroplanes. The heat from the leaks in the exhaust system have caused aluminium fuel lines located immediately behind the firewall to burst. This condition has come about due to a quality control problem at a sub contractor. Cessna has returned all existing inventory to the sub contractor, however it is known that approximately 25 WYE tubes have been distributed to the field since May 1998. This Directive issues instructions to identify and remove from service the defective components. This defect is considered to be an urgent safety of flight issue and hence the inspection must be completed before further flight.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific manufacturing defect in specific aircraft with immediate mandatory action. There is no evidence of scope creep; it remains targeted at the identified safety issue without expanding to unrelated systems or aircraft types."},"complexity_factors":["Single, specific mechanical defect addressed with clear part numbers","Narrow applicability: only one aircraft model (Cessna 414A) and specific serial number range","Simple two-step compliance: identify part number, replace if defective","No nested exceptions or conditional logic — immediate replacement required for all affected parts","Only 4 defined part numbers referenced, no interpretive section","Total length: approximately 250 words"],"plain_english_summary":"This Airworthiness Directive orders owners/operators of Cessna 414A (serials 1–1212) that had the exhaust WYE tube replaced after 1 May 1998 to inspect records or the part number and immediately replace defective WYE tubes (PN 9910299-25 or -26). Replacement must be done before the next flight. It’s urgent: un‑welded WYE tubes can leak exhaust, overheat fuel lines and cause fires or loss of control."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive confines action to the aircraft and parts identified (Model 414A, s/n 1–1212, WYE tubes changed since 01 May 1998) and mandates inspection/replacement of specified P/Ns. It does not broaden the population or introduce additional airworthiness obligations beyond identifying and removing the defective components (Applicability; Requirements; Background)."},"complexity_factors":["Limited applicability — applies only to Model 414A, s/n 1–1212 with a WYE tube changed since 01 May 1998 (Applicability).","Two-step requirement — requires part-number identification (records or physical exam) and conditional removal/replacement of specified P/Ns (Requirement 1 & 2).","Immediate compliance deadline — inspections and replacements must be done 'before further flight', creating urgent operational disruption and potential downtime (Compliance).","Parts substitution condition — replacements may be the specified P/Ns or any WYE tube approved by the aircraft manufacturer, introducing reliance on manufacturer approval (Requirement 2).","Safety-driven provenance — defect arises from a subcontractor quality-control failure; the AD targets removal of potentially distributed faulty units (~25 known) (Background)."],"plain_english_summary":"This directive requires owners/operators of Cessna 414A aeroplanes (serials 1–1212) that had an exhaust WYE tube changed since 1 May 1998 to identify the WYE tube part number and replace P/N 9910299-25 or 9910299-26 with approved replacement parts before further flight. It responds to nonwelded WYE tubes that caused exhaust leaks and ruptured aluminium fuel lines. Operators bear the inspection and replacement costs and must ground affected aircraft until compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-400-109-exhaust-system-components-inspection","history":"/api/acts/ad-cessna-400-109-exhaust-system-components-inspection/history","analysis":"/api/acts/ad-cessna-400-109-exhaust-system-components-inspection/analysis","conflicts":"/api/acts/ad-cessna-400-109-exhaust-system-components-inspection/conflicts","importantCases":"/api/acts/ad-cessna-400-109-exhaust-system-components-inspection/important-cases","documents":"/api/acts/ad-cessna-400-109-exhaust-system-components-inspection/documents"}}