{"id":"F2006B08400","name":"AD/CESSNA 500/26 - Outflow Safety Valve","slug":"ad-cessna-500-26-outflow-safety-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115848,"registerId":"commonwealth-F2006B08400-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 500/26 - Outflow Safety Valve","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 500 (Citation) Series Aeroplanes\n\n \n\nAD/CESSNA 500/26 Outflow Safety Valve 5/96\n\nApplicability: All Cessna 500 series aircraft.\n\n \n\nRequirement: Unless previously carried out, action in accordance with Allied Signal Service Bulletin 103576-21-4056.\n\n \n\nNote: FAA AD 95-25-10 Amdt 39-9456 refers.\n\n \n\nCompliance: Within 200 hours time in service from 25 April 1996 or prior to 31 July 1996, whichever occurs first.\n\n \n\nBackground: The manufacturer has advised that cracking has been found in two valve poppets of a particular batch. This cracking may cause failure of the outflow safety valve which could result in rapid decompression of the aircraft.\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 text does not indicate an expansion or narrowing of the regulator's usual airworthiness-directive powers. It imposes a targeted mandatory maintenance action on a defined aircraft type and references a manufacturer service bulletin and an FAA AD. There is no language in the instrument suggesting a change of scope from established Part 39 airworthiness-directive practice; it simply applies that existing mechanism to this specific safety issue. (Header; Applicability; Requirement; Compliance; Background)"},"complexity_factors":["Narrow and specific applicability: applies only to Cessna 500 series aircraft (Applicability).","Prescriptive reference to an external technical document (Allied Signal Service Bulletin 103576-21-4056) rather than setting out technical steps in the AD (Requirement).","A fixed, time-limited compliance window that is defined by flight hours or a calendar date (Compliance).","Technical subject-matter (aircraft outflow safety valve) requires qualified maintenance personnel to implement the service bulletin (Requirement; Background).","Cross-reference to FAA AD increases the need for operators to consult multiple documents for context (Note)."],"plain_english_summary":"This AD requires all owners/operators of Cessna 500 series aeroplanes to carry out the work specified in Allied Signal Service Bulletin 103576-21-4056 because cracked valve poppets from a production batch could cause outflow valve failure and rapid decompression.  \n\nWork must be done within 200 flight hours from 25 April 1996 or by 31 July 1996, whichever comes first; operators pay for parts, labour and any scheduling impacts."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft series. It has not expanded beyond its original purpose of mandating valve inspections/replacements."},"complexity_factors":["Very short document (approximately 150 words)","Only 1 defined applicability (Cessna 500 series)","Single requirement with clear reference to external technical standard","Simple compliance deadline structure (whichever occurs first)","No nested exceptions or conditional logic","No cross-references to other legislation beyond a single FAA AD note","Straightforward factual background with clear safety rationale"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**Who it affects:** Owners and operators of **Cessna 500 series aircraft** (also known as Citation jets).\n\n**What it requires:** Aircraft operators must inspect or replace certain **outflow safety valves** — these are pressure-release valves that help regulate cabin pressure. The work must follow a specific technical bulletin from the manufacturer (Allied Signal Service Bulletin 103576-21-4056).\n\n**Why it matters:** The manufacturer discovered **cracks in valve components** from a particular production batch. If these valves fail, the aircraft could experience **rapid decompression** — a dangerous situation where cabin pressure drops suddenly, potentially causing loss of consciousness for passengers and crew.\n\n**When it had to be done:** By whichever came first — either within **200 flight hours** after 25 April 1996, or before **31 July 1996**.\n\n**Key point:** This is a **retrospective safety fix**. Even though the aircraft were already certified as airworthy, this directive forced operators to address a newly discovered defect."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-500-26-outflow-safety-valve","history":"/api/acts/ad-cessna-500-26-outflow-safety-valve/history","analysis":"/api/acts/ad-cessna-500-26-outflow-safety-valve/analysis","conflicts":"/api/acts/ad-cessna-500-26-outflow-safety-valve/conflicts","importantCases":"/api/acts/ad-cessna-500-26-outflow-safety-valve/important-cases","documents":"/api/acts/ad-cessna-500-26-outflow-safety-valve/documents"}}