{"id":"F2006B02864","name":"AD/B737/160 - Hydraulic Shutoff Valves","slug":"ad-b737-160-hydraulic-shutoff-valves","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42206,"registerId":"commonwealth-F2006B02864-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)\n\nBoeing 737 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B737/160 Hydraulic Shutoff Valves 9/2","sectionType":"part","heading":"AD/B737/160 Hydraulic Shutoff Valves 9/2001","content":"# AD/B737/160 Hydraulic Shutoff Valves 9/2001\n\nApplicability: All Boeing 737-100, -200, -300, -400, -500, -600, -700, -800 series aeroplanes equipped with hydraulic shutoff valves manufactured by Circle Seal Controls.\n\nNote 1: Only motor operated hydraulic shutoff valves manufactured by Circle Seal Controls that are installed in the locations specified in applicable alert service bulletin (ASB) are subject to this Directive.\n\nRequirement: 1. Perform an operational check of affected motor operated hydraulic shutoff valves in accordance with Boeing ASB 737-29A1073, Revision 3, dated 2 December 1999 or ASB 737-29A1081, dated 2 December 1999, as applicable.\n\nIf any malfunction of the valve is detected, prior to further flight, replace the valve with a new or serviceable Whittaker Controls or Circle Seal Controls valve in accordance with ASB 737-29A1073, Revision 3 or ASB 737-29A1081, as applicable.\n\n    2. Repeat the operational checks for the valves in accordance with ASB 737- 29A1073, Revision 3 or ASB 737-29A1081, as applicable, until the terminating action required by the Requirement 3 of this Directive is accomplished.\n\n    3. Replace the existing Circle Seal Controls valve (identified by Requirement 1), in accordance with ASB 737-29A1078, dated 7 December 2000 or ASB 737- 29A1082, dated 7 December 2000, as applicable.\n\nNote 2: FAA AD 2001-11-07 Amendment 39-12249 refers.\n\nNote 3: Operational checks done before the effective date of this Directive as per Boeing ASB 737-29A1073, Revision 2, dated 1 July 1999 meet Requirements 1 and 2 of this Directive.\n\nNote 4: Replacement of Circle Seal Controls valve done before the effective date of this Directive as per Boeing ASB 737-29A1073, Revision 2, dated 1 July 1999, meets the Requirement 3 of this Directive.","sortOrder":1}],"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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The Directive applies only to the Circle Seal Controls motor‑operated shutoff valves in the ASB‑specified locations on listed 737 models and requires checks and replacement; notes allow earlier work done to earlier ASB revisions to satisfy requirements. The text therefore aligns with the original safety objective and does not expand the pool of affected components or aircraft beyond the ASB‑defined scope."},"complexity_factors":["Technical domain: airworthiness hardware (hydraulic shutoff valves) requiring specialist maintenance skills and tooling.","Multiple cross-references to Boeing Alert Service Bulletins (ASB 737-29A1073, 737-29A1081, 737-29A1078, 737-29A1082) that set the procedures and parts — compliance depends on following external documents.","Applicability narrowed to motor‑operated valves by Circle Seal Controls and only when installed in locations specified by the ASBs (location‑dependent scope).","Two-step compliance regime: recurring operational checks until a terminating replacement action is carried out, creating ongoing scheduling and recordkeeping burdens.","Immediate operational consequence: any detected malfunction requires replacement prior to further flight, creating potential for aircraft downtime and logistical costs.","Permitted replacement parts include Whittaker Controls or Circle Seal Controls valves, introducing parts‑sourcing and interchangeability considerations.","Notes accepting prior compliance under earlier ASB revisions create conditional grandfathering and require traceability of past work.","Reference to FAA AD increases regulatory cross-jurisdictional alignment but requires operators to track multiple authorities' documents."],"plain_english_summary":"This AD requires aircraft operators to perform recurring operational checks of certain motor‑operated hydraulic shutoff valves made by Circle Seal Controls on Boeing 737 series and to replace any valve that malfunctions, following specific Boeing Alert Service Bulletins. It applies to 737‑100 through ‑800 aircraft fitted with those valves. The stated purpose is to correct an identified unsafe valve condition; operators pay for inspections and any replacements and must ground an aircraft with a detected malfunction until a serviceable valve is fitted."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted airworthiness directive focused on a specific unsafe condition (faulty hydraulic valves) on a specific aircraft type. The scope remains tightly constrained to the identified safety issue without expansion into broader operational or maintenance requirements."},"complexity_factors":["Multiple cross-references to external Boeing Alert Service Bulletins (ASB 737-29A1073, ASB 737-29A1081, ASB 737-29A1078, ASB 737-29A1082) with specific revision dates and applicability","Conditional logic: Requirement 2 creates a repeating obligation ('repeat... until') dependent on completion of Requirement 3","Nested applicability: Note 1 further narrows the scope beyond the main applicability section to specific valve locations","Four notes creating exceptions and equivalencies for pre-existing compliance (Notes 3 and 4)","Reference to parallel FAA directive (Note 2) for context but without incorporating its text","Manufacturer name variations and part interchangeability (Circle Seal Controls vs Whittaker Controls)"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection and, if necessary, replacement of Circle Seal Controls hydraulic shutoff valves on Boeing 737s (-100 through -800). It requires repeated operational checks until affected valves are replaced with approved new/serviceable parts.\n\nThe rule applies to operators, airlines and maintenance providers in Australia and aims to prevent loss of hydraulic control. Prior inspections or replacements done under the cited Boeing service bulletins are accepted as compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-160-hydraulic-shutoff-valves","history":"/api/acts/ad-b737-160-hydraulic-shutoff-valves/history","analysis":"/api/acts/ad-b737-160-hydraulic-shutoff-valves/analysis","conflicts":"/api/acts/ad-b737-160-hydraulic-shutoff-valves/conflicts","importantCases":"/api/acts/ad-b737-160-hydraulic-shutoff-valves/important-cases","documents":"/api/acts/ad-b737-160-hydraulic-shutoff-valves/documents"}}