{"id":"F2005L03553","name":"AD/B737/256 - Hydraulic System \"B\" Abex Pump Motor","slug":"ad-b737-256-hydraulic-system-b-abex-pump-motor","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39073,"registerId":"commonwealth-F2005L03553-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/256 | Hydraulic System \"B\" Abex Pump Motor | 13/2005 |\n| ----------- | ------------------------------------ | ------- |\n\n| Applicability: | Boeing Models 737-100, and 737-200 series aeroplanes, equipped with hydraulic system \"B\" Abex P/N 57186 pump motor.                                                                                                                                                                                                                                                                                                                                                                     |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Install the ground fault protection systems in the hydraulic system \"B\" Abex pump motor electric power circuits in accordance with Boeing Service Bulletin 737-29-1029 Revision 2, dated 8 October 1976 or later FAA-approved revisions; or2. Install the hydraulic \"B\" system motor driven pumps, either new or upgraded, in accordance with Boeing Service Bulletin 737-29-1036, dated 30 April 1980, or later FAA-approved revisions.Note: FAA AD 87-02-05R1 Amdt 39-5675 refers. |\n| Compliance:    | Within 30 days after the effective date of this AD, unless previously accomplished.                                                                                                                                                                                                                                                                                                                                                                                                     |\n|                | This Airworthiness Directive becomes effective on 22 December 2005.                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| Background:    | This AD is intended to prevent a hydraulic system \"B\" Abex P/N 57186 pump motor internal wiring fault from burning a hole in the pump motor case and providing an ignition source to any flammable liquids.                                                                                                                                                                                                                                                                             |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n10 November 2005","sortOrder":0},{"sectionNumber":"AD/B737/256","sectionType":"part","heading":"AD/B737/256","content":"## AD/B737/256","sortOrder":1},{"sectionNumber":"Hydraulic System \"B\" Abex Pump Motor","sectionType":"part","heading":"Hydraulic System \"B\" Abex Pump Motor","content":"## Hydraulic System \"B\" Abex Pump Motor","sortOrder":2},{"sectionNumber":"13/2005","sectionType":"part","heading":"13/2005","content":"## 13/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive is consistent with its stated original intent: it targets a specific pump motor part on defined 737 models and mandates two specified corrective options to eliminate an ignition risk. It does not broaden applicability beyond the identified aircraft/part or add new obligations beyond installation of the listed fixes."},"complexity_factors":["Narrow applicability — only Boeing 737‑100/200 with Abex P/N 57186 (low breadth).","Two alternative corrective actions are permitted (choice and procurement burden on operators).","Mandated compliance time is short (30 days), increasing operational disruption risk.","Reliance on external documents (two specific Boeing service bulletins) and \"FAA‑approved revisions\" introduces dependency on third‑party and regulator approvals.","Enforcement and verification rest with CASA; no detailed testing/inspection protocol is included in the AD text itself.","Reference to a prior FAA AD adds cross‑jurisdictional linkage but does not expand technical detail."],"plain_english_summary":"**What it does:** This Airworthiness Directive requires operators of Boeing 737‑100 and 737‑200 aircraft fitted with hydraulic system \"B\" Abex pump motor P/N 57186 to either install ground‑fault protection per Boeing Service Bulletin 737‑29‑1029 (or later FAA‑approved revisions) or install new/upgraded hydraulic B motor‑driven pumps per Boeing Service Bulletin 737‑29‑1036. Compliance is required within 30 days.\n\n**Why it matters:** The AD aims to prevent an internal wiring fault in the pump motor from burning through the case and igniting flammable liquids. Operators pay for and choose the corrective option; CASA enforces compliance."},"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"},"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 specific aircraft. It has not expanded beyond its original purpose of mitigating fire risk from a known pump motor fault."},"complexity_factors":["Single, clearly defined applicability (two specific aircraft models, one specific part number)","Only two alternative compliance methods, both referencing specific Boeing Service Bulletins","No defined terms section or interpretation provisions","Simple, unconditional compliance deadline (30 days)","No cross-references to other legislation beyond a single note about the corresponding FAA directive","Straightforward background explanation with single causal chain (wiring fault → hole in case → ignition source)"],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 737‑100/-200 aircraft with Abex pump motor P/N 57186 to correct a hazardous internal wiring fault that can burn through the pump case, allowing hydraulic fluid to leak and ignite. Within 30 days operators must either fit electrical ground‑fault protection or replace/upgrade the pump. The rule prevents potential in‑flight fires and loss of hydraulic control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-256-hydraulic-system-b-abex-pump-motor","history":"/api/acts/ad-b737-256-hydraulic-system-b-abex-pump-motor/history","analysis":"/api/acts/ad-b737-256-hydraulic-system-b-abex-pump-motor/analysis","conflicts":"/api/acts/ad-b737-256-hydraulic-system-b-abex-pump-motor/conflicts","importantCases":"/api/acts/ad-b737-256-hydraulic-system-b-abex-pump-motor/important-cases","documents":"/api/acts/ad-b737-256-hydraulic-system-b-abex-pump-motor/documents"}}