{"id":"F2006B02862","name":"AD/B737/159 - Engine Fuel Shutoff Valve Wiring","slug":"ad-b737-159-engine-fuel-shutoff-valve-wiring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42204,"registerId":"commonwealth-F2006B02862-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \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.","sortOrder":0},{"sectionNumber":"AD/B737/159 Engine Fuel Shutoff Valve Wi","sectionType":"part","heading":"AD/B737/159 Engine Fuel Shutoff Valve Wiring 9/2001","content":"# AD/B737/159 Engine Fuel Shutoff Valve Wiring 9/2001\n\nApplicability: The following models and series of aeroplanes as listed in the Service Bulletins (SB) below:\n\nAeroplane Model Boeing Special Attention Service Bulletin\n\n737-300, 737-400, 737-500 737-28-1164, dated 24 August 2000.\n\n737-600, 737-700, 737-800 737-28-1160, Revision 1, dated 26 October 2000.\n\nRequirement: 1. Perform a test to determine if there is continuity or to measure voltage, as applicable, of the two electrical circuits that close the fuel shutoff valve on the wing spar. Carry out the test in accordance with Special Attention SB 737-28- 1164 or SB 737-28-1164, Revision 1, dated 10 May 2001 (for Model 737-300, 737-400, and 737-500 series aeroplanes); or Special Attention SB 737-28-1160, Revision 1 (for Model 737-600, 737-700, and 737-800 series aeroplanes).\n\n    2. For Model 737-300, 737-400 and 737-500 series aeroplanes \\- If any discontinuity is detected, repair the discontinuity in accordance with SB 737-28- 1164.\n\n    3. For Model 737-600, 737-700 and 737-800 series aeroplanes \\- If any measurement is not between 21 and 34 volts direct current (DC), repair the discrepancy in accordance with SB 737-28-1160, Revision 1.\n\nNote 1: Tests accomplished per Special Attention SB 737-28-1160 (for Model 737- 600, 737-700 and 737-800 series aeroplanes), dated 5 June 2000 are acceptable for compliance with this Directive.\n\nNote 2: Tests accomplished prior to the effective date of this Directive per Boeing All Base Telex M-7200-00-01064, dated 24 April 2000; Boeing Telex SWA-DAL-00- 00182H, dated 27 March, 2000; Boeing Telex CAL-IAH-00-00681H, dated 17 April 2000; Boeing All Base Telex M-7200-00-01231, dated 31May 2000; or Boeing Telex AAL-AFW-00-00324H, dated 27 March 2000; are acceptable for compliance with this Directive.\n\nNote 3: FAA AD 2001-13-07 Amdt 39-12287 refers.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific unsafe wiring condition in specific Boeing 737 models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Multiple aircraft model groupings with slightly different technical requirements (continuity test vs voltage measurement)","Cross-references to five external Boeing Service Bulletins and Telex documents for compliance methods","Reference to corresponding FAA AD (US regulator's equivalent directive)","Three explanatory notes creating exceptions/acceptable alternative compliance paths","Technical aviation terminology requiring specialised knowledge (continuity, voltage DC, wing spar, fuel shutoff valve)"],"plain_english_summary":"This AD requires operators of Boeing 737-300/-400/-500/-600/-700/-800 series to test the electrical wiring for engine fuel shutoff valves—continuity tests for older models and 21–34 V DC voltage checks for newer models—and repair any out-of-spec wiring per Boeing instructions.\n\nIt’s mandatory to prevent loss of the ability to shut down an engine in an emergency; prior equivalent tests under earlier Boeing bulletins are accepted as compliance."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD remains narrowly focused on identifying and repairing faults in the electrical circuits that close the wing-spar fuel shutoff valve for the listed Boeing 737 models. It requires testing and repair in accordance with specified Boeing Service Bulletins and accepts certain prior Boeing telexes or earlier SB versions as satisfying the requirement. There is no indication in the text provided that the instrument has expanded beyond that original safety-focused purpose; it does not add unrelated obligations, broaden applicability beyond the listed models, nor change the nature of the remedy (testing and repair per manufacturer guidance)."},"complexity_factors":["Short instrument with 3 numbered mandatory requirements","Applicability limited to specific Boeing 737 series referenced to two primary Service Bulletins (SB 737-28-1164 and SB 737-28-1160 Rev 1)","Cross-references to multiple external documents (two SBs, several Boeing telexes, and an FAA AD) that determine compliance details","Two different technical tests depending on model group: continuity test for 737-300/400/500 and voltage range check (21–34 V DC) for 737-600/700/800","Three explanatory notes allowing earlier tests/documents to be accepted for compliance","No separate interpretation/definitions section in the excerpt (low internal terminology load)"],"plain_english_summary":"**What this instrument does (mechanics first)**\n\n- This is an Airworthiness Directive (AD) that requires operators of certain Boeing 737 models to test the electrical wiring that operates the wing-spar fuel shutoff valve and, if problems are found, to repair them following Boeing service instructions. (An AD is a regulatory order that requires action to correct an identified unsafe condition on an aircraft.)\n\n- The AD applies to specific 737 model series as listed in the Boeing service bulletins cited: 737-300/400/500 (see SB 737-28-1164) and 737-600/700/800 (see SB 737-28-1160, Rev 1). (Applicability section.)\n\n- Required steps:\n  - Perform a continuity/voltage test of the two electrical circuits that close the fuel shutoff valve on the wing spar in accordance with the relevant Boeing Special Attention Service Bulletin. (Requirement 1.)\n  - For 737-300/400/500: if any electrical discontinuity is found, repair it per SB 737-28-1164. (Requirement 2.)\n  - For 737-600/700/800: if any measured voltage is outside the range 21–34 volts DC, repair per SB 737-28-1160, Rev 1. (Requirement 3.)\n\n- The AD accepts certain earlier Boeing telexes and an earlier version of the SB as meeting the requirement if the tests were already done before the AD’s effective date. (Notes 1–2.)\n\n**Why the regulator says it matters (stated purpose)**\n\n- The CASA delegate issues the AD as the action considered necessary to correct an “unsafe condition” related to the fuel shutoff valve wiring (see header). The AD therefore mandates inspection and corrective action intended to ensure the valve circuits are electrically serviceable.\n\n**Who pays and who decides**\n\n- Aircraft operators/owners of the affected 737 series bear the cost of performing the tests and any repairs (Requirement 1–3). \n- The AD requires repairs to follow Boeing’s specified Service Bulletins, so Boeing’s SBs determine the technical method of compliance (Requirement 1–3). The CASA delegate enforces compliance under the aviation regulations (header).\n\n**Behavioural change required**\n\n- Maintenance organisations must add the specified continuity/voltage checks to their maintenance actions for affected aeroplanes and must carry out repairs if the circuits fail the test limits. Operators who already did equivalent tests under specified earlier Boeing telexes/SBs may treat those as compliant (Notes 1–2).\n\n**Costs, incentives and trade‑offs — practical effects and risks**\n\n- Direct costs: labour and any parts or rewiring needed to repair discontinuities or voltage abnormalities. The work may require out-of-service time for affected aircraft, which is an opportunity cost for operators (Requirement 2–3).\n\n- Compliance burden: the AD cross-references Boeing Special Attention Service Bulletins as the instructions for both testing and repair; following the AD therefore requires access to and reliance on those manufacturer documents (Requirement 1–3). \n\n- Implementation risks: measurement error, test variability between maintenance organisations, or inconsistent interpretation of SB instructions can affect whether a unit is repaired; the AD allows certain prior tests and documents to satisfy compliance, which shifts some judgement to records review (Notes 1–2).\n\n- Effects on competition and private choice: the AD imposes uniform regulatory requirements on all operators of the listed 737 series. Smaller operators with less spare capacity may feel the operational impact more, because maintenance and grounded time have fixed-cost effects. The requirement itself does not alter ownership, fares, or contracting freedom directly — it imposes a maintenance obligation.\n\n- Role of the manufacturer: because the AD prescribes compliance in accordance with Boeing Service Bulletins and accepts specific Boeing telexes, Boeing’s repair instructions determine the remedial action; that channels technical resolution through the manufacturer’s guidance (Requirement 1–3; Notes 1–2).\n\n**Trade-offs and substitution effects**\n\n- The AD reduces the risk of fuel-shutoff-valve electrical failure by mandating verification and repair. The trade-off is operator cost and aircraft downtime.\n\n- Operators who already performed the tests under the listed earlier Boeing telexes or SB versions need not repeat them (Notes 1–2), reducing duplicate work where records exist.\n\n**Concentrated benefits and costs**\n\n- Concentrated benefit: improved assurance that the fuel shutoff valve closure circuits are electrically serviceable on the listed aircraft — a safety benefit concentrated for passengers, crew, and the operator.\n\n- Concentrated cost: operators of the affected 737 series bear the inspection and repair cost and scheduling impact.\n\n**Regulatory harmonisation**\n\n- The AD refers to an FAA airworthiness directive (FAA AD 2001-13-07) as related authority (Note 3), which shows cross-validation with the FAA’s action and supports international alignment of the remedy.\n\n**Bottom line (plain)**\n\n- If you operate the listed Boeing 737 models you must test the two electrical circuits that close the fuel shutoff valve per the cited Boeing Service Bulletins and repair any discontinuity or out-of-range voltage per those same bulletins. The tests follow Boeing’s detailed instructions, some older Boeing documents are acceptable if they were used before the AD took effect, and the regulator enforces compliance under the airworthiness rules (Requirement 1–3; Notes 1–3)."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-159-engine-fuel-shutoff-valve-wiring","history":"/api/acts/ad-b737-159-engine-fuel-shutoff-valve-wiring/history","analysis":"/api/acts/ad-b737-159-engine-fuel-shutoff-valve-wiring/analysis","conflicts":"/api/acts/ad-b737-159-engine-fuel-shutoff-valve-wiring/conflicts","importantCases":"/api/acts/ad-b737-159-engine-fuel-shutoff-valve-wiring/important-cases","documents":"/api/acts/ad-b737-159-engine-fuel-shutoff-valve-wiring/documents"}}