{"id":"F2005L03166","name":"AD/B737/251 - Smiths Industries Aerospace Flight Management Computers","slug":"ad-b737-251-smiths-industries-aerospace-flight-management-computers","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":134402,"registerId":"commonwealth-F2005L03166-current","compilationNumber":null,"startDate":"2026-04-03","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/B737/251 | Smiths Industries Aerospace Flight Management Computers | 12/2005 |\n| ----------- | ------------------------------------------------------- | ------- |\n\n| Applicability: | Model 737-300, -400, -500, -600, -700, -700C, -800 and -900 series aeroplanes, equipped with two Smiths Industries Aerospace Flight Management Computers (FMC) having part number 171497-05-01 or 176200-01-01; installed with operational program software (OPS) version U10.3, U10.4, U10.4A or U10.5.                                                                                                                                                                                    |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Carry out the following in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin (ASB) 737-34A1801, dated 15 July 2004 (for Model 737- 600, -700, -700C, -800 and -900 series aeroplanes) or Boeing ASB 737-34A1821, dated 15 July 2004 (for Model 737- 300, -400 and -500 series aeroplanes); as applicable.                                                                                                                                                 |\n|                | a. Install the updated version of the OPS, the compatible model/engine database (MEDB) software if applicable, the current version of the navigational database (NDB) software, and the software options database (OPC) in the left and right FMCs.                                                                                                                                                                                                                                         |\n|                | b. Do configuration checks of the left and right FMCs to ensure that the updated version of the OPS, compatible version of the MEDB software if applicable, and OPC software is correctly installed.                                                                                                                                                                                                                                                                                        |\n|                | 2. If the incorrect software version of the OPS, MEDB software if applicable, or OPC software is found installed on any FMC during any configuration check required by Requirement 1, reinstall the applicable software in accordance with the Accomplishment Instructions ASB 737-34A1801 or ASB 737-34A1821, as applicable.                                                                                                                                                               |\n|                | Optional installation of software in accordance with the Accomplishment Instructions of Boeing Service Bulletin (SB) 737-34-1768, dated 11 August 2005 (for Model 737-600, -700, -700C, -800 and -900 series aeroplanes); or Boeing SB 737-34-1879, dated 11 August 2005 (for Model 737-300, -400 and -500 series aeroplanes), as applicable, is acceptable for compliance with the corresponding requirements of Requirements 1 and 2 providing the following sub-paragraphs are followed: |\n\n|             | a. Install version U10.6 of the OPS software, the applicable OPC software, the new compatible MEDB software if applicable, and the NDB software in the left and right FMCs; install the common display system (CDS) OPC software in the left and right display electronic units if applicable; and do configuration checks to ensure that certain software is properly installed.                                             |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|             | b. If the incorrect software version of the OPS, OPC software, CDS OPC software if applicable, or MEDB software if applicable, is found installed during any configuration check required by the above sub-paragraph, before further flight, reinstall the software, in accordance with the applicable service bulletin.                                                                                                      |\n|             | Later revisions of the above ASBs or SBs, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2005-19-19, are considered acceptable for compliance with the equivalent Requirements of this Directive.                                                                                                                                                  |\n|             | Note 3: FAA AD 2005-19-19 Amdt 39-14284 refers.                                                                                                                                                                                                                                                                                                                                                                               |\n| Compliance: | For Requirement 1 - Within 180 days after the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                               |\n|             | For Requirement 2 - Before further flight, after the Requirement 1.b. configuration check.                                                                                                                                                                                                                                                                                                                                    |\n|             | This Airworthiness Directive becomes effective on 24 November 2005.                                                                                                                                                                                                                                                                                                                                                           |\n| Background: | The United States Federal Aviation Administration (FAA) has received advice from an operator reporting FMC map shifts on several Model 737-400 series aeroplanes with dual FMCs, using OPS version U10.4A. This condition if not corrected could prevent adequate alerting of a potential navigation error and could result in a near miss with other aeroplanes or terrain, or collision if other warning systems also fail. |\n|             | This Directive requires the installation of an updated version of the operational program software (OPS) and certain other software in the flight management computers (FMCs) together with the completion of configuration checks to ensure that certain software is properly installed.                                                                                                                                     |\n\n![](image.001.png)  \nJayaprakashan Ambali  \nDelegate of the Civil Aviation Safety Authority\n\n12 October 2005","sortOrder":0},{"sectionNumber":"AD/B737/251","sectionType":"part","heading":"AD/B737/251","content":"## AD/B737/251","sortOrder":1},{"sectionNumber":"Smiths Industries Aerospace Flight Manag","sectionType":"part","heading":"Smiths Industries Aerospace Flight Management Computers","content":"## Smiths Industries Aerospace Flight Management Computers","sortOrder":2},{"sectionNumber":"12/2005","sectionType":"part","heading":"12/2005","content":"## 12/2005","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive addressing a specific software defect in specific aircraft configurations. The scope remains precisely limited to the identified safety issue (FMC map shifts) and the affected equipment. The alternative compliance pathway using later service bulletins is a standard regulatory flexibility, not scope creep."},"complexity_factors":["Multiple alternative compliance pathways (primary ASB route vs optional SB route with different software versions)","Extensive cross-referencing to external Boeing documents (ASB 737-34A1801, ASB 737-34A1821, SB 737-34-1768, SB 737-34-1879)","Conditional logic ('if applicable') appearing 8+ times regarding MEDB and CDS OPC software","Nested requirements (Requirement 2 triggers only if Requirement 1.b finds errors)","Specific part numbers and software version numbers (U10.3, U10.4, U10.4A, U10.5, U10.6) that must be precisely matched","Dual applicability matrices (different service bulletins for different aircraft model ranges: -300/-400/-500 vs -600/-700/-800/-900)","Reference to foreign regulatory approval (FAA AMOC acceptance for later revisions)"],"plain_english_summary":"This mandatory CASA directive forces operators of certain Boeing 737s with specific Smiths Industries FMCs to update flight‑management software to stop a “map shift” that can show the aircraft in the wrong location. It requires installing updated OPS/MEDB/NDB/OPC software in both FMCs, running configuration checks, and fixing any errors before flight.\n\nIt matters because the bug can produce unannounced navigation errors with serious safety risk; compliance was required within 180 days of 24 Nov 2005."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope remains focused on the originally targeted aircraft, FMC part numbers and OPS versions. The Directive prescribes software updates and configuration checks to address reported FMC map shifts and does not expand requirements beyond those applicability criteria (Applicability; Requirement; Compliance)."},"complexity_factors":["Multiple affected aeroplane models across the 737 series increases coordination effort (Applicability).","Requirement ties compliance to specific FMC part numbers (171497-05-01, 176200-01-01) and OPS software versions (U10.3–U10.5) creating precise scope.","Several distinct software items must be managed: OPS, MEDB, NDB, OPC and optionally CDS OPC, increasing technical steps and verification.","Compliance procedure requires both installation and configuration checks, with immediate reinstallation before further flight if incorrect software is detected (Requirements 1–2).","Two alternative Boeing service bulletins (ASB/SB sets) for different model groups and an FAA‑approved AMOC route introduce cross-references and dependency on external approvals.","Differing timelines (180 days for initial install; before further flight for corrective reinstall) create operational scheduling constraints.","Costs and downtime fall on operators; technical competence and access to correct software/media are preconditions to compliance."],"plain_english_summary":"This Directive requires affected Boeing 737 operators to update the software in both Smiths flight management computers (FMCs) (specific part numbers) and run configuration checks, reinstalling any incorrect versions before further flight. It applies to listed 737-300/400/500/600/700/700C/800/900 series aeroplanes with specified OPS versions. Operators pay for the software updates and any downtime; the regulator sets deadlines (install within 180 days; incorrect installs fixed before flight) and accepts FAA‑approved alternative service bulletins. The change targets a reported FMC map‑shift safety risk."},"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-b737-251-smiths-industries-aerospace-flight-management-computers","history":"/api/acts/ad-b737-251-smiths-industries-aerospace-flight-management-computers/history","analysis":"/api/acts/ad-b737-251-smiths-industries-aerospace-flight-management-computers/analysis","conflicts":"/api/acts/ad-b737-251-smiths-industries-aerospace-flight-management-computers/conflicts","importantCases":"/api/acts/ad-b737-251-smiths-industries-aerospace-flight-management-computers/important-cases","documents":"/api/acts/ad-b737-251-smiths-industries-aerospace-flight-management-computers/documents"}}