{"id":"F2006B02851","name":"AD/B737/149 - Autothrottle Computer","slug":"ad-b737-149-autothrottle-computer","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42193,"registerId":"commonwealth-F2006B02851-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/B737/149 Autothrottle Computer 1/2001","sectionType":"part","heading":"AD/B737/149 Autothrottle Computer 1/2001","content":"# AD/B737/149 Autothrottle Computer 1/2001\n\nApplicability: All Model 737-300, \\-400, and \\-500 series aeroplanes.\n\nRequirement: 1. Replace the existing autothrottle computer with a new, improved autothrottle computer in accordance with Boeing Alert Service Bulletin 737-22A1130 dated 24 September 1998.\n\n2. Autothrottle computers with Part Numbers 10-62017-1, \\-2, \\-3, \\-4, \\-5, \\-11, \\-21, \\-23,\n\n\\-25, or \\-27 may not be fitted to any aeroplane to replace an installed computer.\n\nNote: FAA AD 2000-23-34 Amdt 39-12007 refers.\n\nCompliance: For Requirement 1 \\- Within 18 months after the effective date of this Directive.\n\nFor Requirement 2 \\- As of the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 25 January 2001.\n\nBackground: The aircraft manufacturer has received several reports of asymmetric thrust conditions during flight caused by irregular autothrottle operation in which the thrust levers slowly move apart causing the aeroplane to bank excessively and go into a roll.\n\nThis Directive requires replacement of the existing autothrottle computer with a new, improved autothrottle computer. This action is intended to prevent a severe asymmetric thrust condition developing during flight, which could result in loss of control of the aeroplane.\n\n![Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.](image.003.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 11 December 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 20 December 2000.","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":3,"scope_assessment":{"changed":false,"description":"The Directive applies only to the specified 737-300/-400/-500 series and mandates replacement plus an immediate ban on listed replacement part numbers. It does not expand applicability beyond those models and limits allowable replacement parts as of the effective date; action aligns with the referenced Boeing service bulletin and the FAA AD noted in the instrument."},"complexity_factors":["Narrow applicability limited to all Model 737-300, -400 and -500 aeroplanes (Applicability).","Single, specific technical remedy: replace autothrottle computer per Boeing Alert Service Bulletin 737-22A1130 (Requirement 1).","Immediate prohibition on fitting specified part numbers as replacements (Requirement 2 — effective date immediate).","Fixed compliance deadline of 18 months for the replacement action (Compliance).","Dependence on availability and installation of the improved autothrottle computer (Requirement 1 — procurement/installation burden on operators).","Cross-reference to FAA AD 2000-23-34 and a manufacturer service bulletin (Note/Requirement) introduces coordination with external technical documents.","Statutory basis under subregulation 39.1(1) of CAR 1998 and discretionary issuance by CASA delegate (preamble/signature)."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 737-300, -400 and -500 aeroplanes to replace the autothrottle computer with a new, improved unit and forbids fitting certain listed autothrottle part numbers. It responds to reports of irregular autothrottle behaviour that produced asymmetric thrust and a risk of loss of control. Replacement must follow Boeing Alert Service Bulletin 737-22A1130 and be completed within 18 months; the prohibition on listed parts is effective immediately, so operators must procure and install the approved unit and meet the compliance timeframe."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific safety defect in a specific aircraft component. It has not expanded beyond the original purpose of correcting the autothrottle computer malfunction."},"complexity_factors":["Single, clearly defined applicability (three specific Boeing 737 models)","Only two straightforward requirements with no nested conditions","Simple compliance timeline (18 months for replacement, immediate for prohibition)","No defined terms section or interpretive provisions","No cross-references to other legislation beyond a single FAA reference note","Background section provides clear factual context without legal complexity"],"plain_english_summary":"This Airworthiness Directive from CASA requires all Boeing 737-300/‑400/‑500 aircraft in Australia to have the autothrottle computer replaced with an improved unit within 18 months and forbids reinstalling specified older part-numbered units. It addresses dangerous asymmetric-thrust failures that can cause excessive roll and loss of control, mandating the upgrade to prevent possible catastrophic accidents."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-149-autothrottle-computer","history":"/api/acts/ad-b737-149-autothrottle-computer/history","analysis":"/api/acts/ad-b737-149-autothrottle-computer/analysis","conflicts":"/api/acts/ad-b737-149-autothrottle-computer/conflicts","importantCases":"/api/acts/ad-b737-149-autothrottle-computer/important-cases","documents":"/api/acts/ad-b737-149-autothrottle-computer/documents"}}