{"id":"F2006B02840","name":"AD/B737/139 - Wire Bundle Chafing - Electric Motor Driven Hydraulic Pump","slug":"ad-b737-139-wire-bundle-chafing-electric-motor-driven-hydraulic-pump","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42182,"registerId":"commonwealth-F2006B02840-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B737/139 - Wire Bundle Chafing - Electric Motor Driven Hydraulic Pump","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)  \nBoeing 737 Series Aeroplanes\n\nAD/B737/139 Wire Bundle Chafing \\- Electric Motor\n\nDriven Hydraulic Pump\n\n  \n3/2000\n\nApplicability: Model 737-300, -400, and -500 series aeroplanes, as listed in Boeing Alert Service (ASB) Bulletin 737-29A1076, Revision 1, dated 21 October 1999; and Model 737- 600, -700, and -800 series aeroplanes, as listed in Boeing ASB 737-29A1077, Revision 1, dated 21 October 1999.\n\nRequirement: 1. For Model 737-300, \\-400, and \\-500 series aeroplanes:\n\n    Without Boeing ASB 737-29A1076 dated 2 April 1998 accomplished \\- Perform a one-time detailed visual inspection of wire bundle W0334 and the hydraulic case drain and pressure hoses for the electric motor driven pump (EMDP) for hydraulic system \"B\" to detect any discrepancy (e.g. damage or chafing of wire bundle W0334 and the hydraulic case drain and pressure hoses; and incorrect separation between those components), in accordance with Part 1 of the Accomplishment Instructions of Boeing ASB 737-29A1076, Revision 1, dated 21 October 1999.\n\n    b. With Boeing ASB 737-29A1076 dated 2 April 1998 accomplished - Perform a one-time detailed visual inspection of wire bundle W0334 and the hydraulic case drain and pressure hoses for the EMDP for hydraulic system \"B\" to detect any discrepancy (e.g. damage or chafing of wire bundle W0334 and the hydraulic case drain and pressure hoses; and incorrect separation between those components), in accordance with Part 2 of the Accomplishment Instructions of Boeing 737-29A1076, Revision 1, dated 21 October 1999.\n\n    2. If any discrepancy is found, during the Requirement 1.a. inspection, perform corrective actions in accordance with Part 1 of the Accomplishment Instructions of ASB 737-29A1076, Revision 1.\n\n    3. If any discrepancy is found, during the Requirement 1.b. inspection, perform corrective actions in accordance with Part 2 of the Accomplishment Instructions of ASB 737-29A1076, Revision 1.\n\n    4. For Model 737-600, \\-700, and \\-800 series aeroplanes:\n\n    Without Boeing ASB 737-29A1077 dated 4 March 1999 accomplished - Perform a one-time detailed visual inspection of wire bundle W5230 and the hydraulic case drain and pressure hoses for the EMDP for hydraulic system \"B\" to detect any discrepancy (e.g. damage or chafing of the W5230 wire bundle and the hydraulic case drain and pressure hoses; and incorrect separation between those components) in accordance with Part 1 of the Accomplishment Instructions of Boeing ASB 737-29A1077, Revision 1, dated 21 October 1999.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n    b. With Boeing ASB 737-29A1077, dated 4 March 1999 accomplished - Perform a one-time detailed visual inspection of wire bundle W5230 and the case drain and pressure hoses for the EMDP for hydraulic system \"B\" to detect any discrepancy (e.g. damage or chafing of the W5230 wire bundles and the hydraulic case drain and pressure hoses; and incorrect separation between those components), in accordance with Part 2 of Boeing ASB 737-29A1077, Revision 1, dated 21 October 1999.\n\n    5. If any discrepancy is found during the Requirement 4.a. inspection, perform corrective actions in accordance with Part 1 of the Accomplishment Instructions of the ASB 737-29A1077, Revision 1.\n\n    6. If any discrepancy is found during the Requirement 4.b. inspection, perform corrective actions in accordance with Part 2 of the Accomplishment Instructions of ASB 737-29A1077, Revision 1.\n\nNote 1: For the purposes of this Directive, a detailed visual inspection is defined as: \"An intensive examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate by the inspector. Inspection aids such as mirrors, magnifying lenses, etc. may be used. Surface cleaning and elaborate access procedures may be required.\"\n\nNote 2: FAA AD 99-26-21 Amdt 39-11480 refers.\n\nCompliance: For Requirement 1 \\- Within 90 days of the effective date of this Directive.\n\nFor Requirement 2 \\- Prior to further flight. For Requirement 3 \\- Prior to further flight.\n\nFor Requirement 4 \\- Within 90 days of the effective date of this Directive. For Requirement 5 - Prior to further flight.\n\nFor Requirement 6 \\- Prior to further flight.\n\nThis Airworthiness Directive becomes effective on 23 March 2000.\n\nBackground: The aircraft manufacturer has received report of the wire bundle to the Hydraulic System “B” EMDP being chafed. This Directive requires a one time inspection to detect discrepancies and, if necessary, correct the discrepancies. These actions are intended to prevent electrical arcing, with the subsequent risk of fire, being caused by chafing of the wire bundle.","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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD adheres to the original safety purpose: a one-time inspection and repair requirement to eliminate chafing risk on specified wire bundles adjacent to the EMDP hydraulic hoses. It does not materially expand beyond that objective. The Directive accommodates whether earlier Boeing ASBs were already accomplished (two inspection tracks) and covers two model groups, but those are implementation details rather than a substantive broadening of scope."},"complexity_factors":["Two distinct model groups (737-300/-400/-500 and 737-600/-700/-800) with separate wire-bundle identifiers (W0334 and W5230)","Two Boeing Alert Service Bulletins referenced (ASB 737-29A1076 and ASB 737-29A1077), each with Part 1 and Part 2 instructions","Conditional branches depending on whether an earlier ASB had already been accomplished (Requirement 1.a vs 1.b and 4.a vs 4.b)","Six numbered mandatory requirements plus multiple compliance deadlines (90 days for initial inspections; 'prior to further flight' for corrective actions)","Defined term: detailed visual inspection is explicitly defined in Note 1 (adds procedural detail to what inspection entails)","Corrective-action dependency: fixes must follow the ASB Part corresponding to the inspection path (links requirement to external procedural document)","Cross-reference to an FAA AD (99-26-21) for related guidance"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Requires one-time detailed visual inspections of specific electrical wire bundles and nearby hydraulic hoses around the electric motor driven hydraulic pump (EMDP) for hydraulic System B on certain Boeing 737 models.  The inspections must follow the step-by-step Accomplishment Instructions in the referenced Boeing Alert Service Bulletins (ASBs).\n\n- If the inspection finds any \"discrepancy\" (examples given: chafing or damage to the wire bundle or hoses, or incorrect separation between them), the operator must carry out the corrective actions specified in the same ASB parts before the airplane flies again.\n\n- There are two parallel tracks depending on whether an earlier Boeing ASB has already been complied with. Each model group has a “without earlier ASB compliance” inspection (Part 1 of the ASB) and a “with earlier ASB compliance” inspection (Part 2 of the ASB).\n\n- Compliance times: the initial inspections must be done within 90 days of the AD taking effect. Any required corrective actions must be done prior to further flight (i.e. the aeroplane cannot be flown until the fixes are completed).\n\n- The AD defines \"detailed visual inspection\" (lighting, inspection aids, cleaning and access may be required) and cross-references an FAA AD for related information.\n\nWho this affects\n\n- Operators, owners and maintenance organisations responsible for Boeing 737-300, -400, -500, -600, -700 and -800 series aircraft listed in the specified Boeing ASBs.\n\n- Maintenance personnel who must perform the inspections and implement corrective actions in accordance with the ASB instructions.\n\nWhy it matters (stated safety objective and practical implications)\n\n- Stated objective: prevent electrical arcing (and the consequent risk of fire) that could be caused by chafing of the specified wire bundle where it lies close to hydraulic case drain and pressure hoses for the EMDP on hydraulic System B.\n\n- Practical effects: operators must allocate maintenance time and possibly parts and labour to inspect the specified wiring/hose areas and to carry out any required repairs or rerouting before returning an aircraft to service. Aircraft found with discrepancies will be grounded until corrected, producing direct costs (labour, parts, downtime).\n\nOperational mechanics and incentives\n\n- Who pays: aircraft operators/owners pay for inspection labour, any corrective repairs, and downtime costs.\n\n- Who decides: maintenance inspectors perform the inspection and apply the corrective actions required by the ASB; the Civil Aviation Safety Authority (CASA) enforces the AD and sets the effective and compliance dates.\n\n- Behaviour change required: schedule and complete a one-time targeted inspection per the ASB, and follow the ASB's prescribed repairs if damage is found.\n\nTrade-offs, implementation risk and compliance burden\n\n- The AD imposes a one-time compliance burden rather than an ongoing inspection programme, so the recurring administrative cost is limited.\n\n- If many aircraft show damage, operators could face concentrated repair costs and temporary reductions in available aircraft.\n\n- The inspection relies on maintenance personnel following the ASB step instructions; the AD points to two different ASB Parts depending on prior work, which creates a small risk of confusion if records of prior ASB compliance are incomplete.\n\n- The AD focuses on a specific failure mode (chafing of particular wire bundles W0334 or W5230 adjacent to EMDP hoses). It does not mandate inspection of other wiring that may present different but related hazards.\n\nReference to the Directive text\n\n- Requirements are numbered 1–6 in the Directive: Requirements 1–3 cover 737-300/-400/-500 (wire bundle W0334) and Requirements 4–6 cover 737-600/-700/-800 (wire bundle W5230).  Note 1 defines \"detailed visual inspection.\" The compliance schedule is specified under \"Compliance.\" The Directive cites Boeing ASB 737-29A1076 (for -300/-400/-500) and ASB 737-29A1077 (for -600/-700/-800), Revision 1, dated 21 October 1999, as the required procedural source.\n\n"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific safety issue (wire bundle chafing on specific Boeing 737 hydraulic systems) identified through manufacturer reports. The directive does not expand beyond its original technical safety purpose."},"complexity_factors":["Multiple aircraft model variants with different requirements (737-300/400/500 vs 737-600/700/800)","Bifurcated requirements based on prior maintenance history (whether specific Boeing Service Bulletins were already accomplished)","Cross-references to external Boeing documents (ASB 737-29A1076 and ASB 737-29A1077, Revision 1) for detailed instructions","Specific wire bundle identifiers (W0334 vs W5230) that differ between aircraft series","Nested conditional logic: different inspection parts (Part 1 vs Part 2) and different corrective action parts depending on prior compliance status","Technical aviation terminology requiring specialized knowledge (EMDP, case drain hoses, detailed visual inspection)","Multiple compliance deadlines with different triggers (90 days vs prior to further flight)"],"plain_english_summary":"Australia’s aviation regulator (CASA) has issued a safety order requiring operators of certain Boeing 737 Classic (‑300/‑400/‑500) and Next Generation (‑600/‑700/‑800) aircraft to inspect a wire bundle near the B hydraulic pump for chafing against hydraulic hoses. \n\nInspections (within 90 days) must check for damage and improper spacing, and any defects must be rectified before flight to prevent electrical arcing and potential in‑flight fires."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-139-wire-bundle-chafing-electric-motor-driven-hydraulic-pump","history":"/api/acts/ad-b737-139-wire-bundle-chafing-electric-motor-driven-hydraulic-pump/history","analysis":"/api/acts/ad-b737-139-wire-bundle-chafing-electric-motor-driven-hydraulic-pump/analysis","conflicts":"/api/acts/ad-b737-139-wire-bundle-chafing-electric-motor-driven-hydraulic-pump/conflicts","importantCases":"/api/acts/ad-b737-139-wire-bundle-chafing-electric-motor-driven-hydraulic-pump/important-cases","documents":"/api/acts/ad-b737-139-wire-bundle-chafing-electric-motor-driven-hydraulic-pump/documents"}}