{"id":"F2006B03201","name":"AD/B747/308 - Air Data System","slug":"ad-b747-308-air-data-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42573,"registerId":"commonwealth-F2006B03201-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\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 CASR 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.\n\n![](image.001.png)  \n\nBoeing 747 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B747/308 Air Data System 8/2004","sectionType":"part","heading":"AD/B747/308 Air Data System 8/2004","content":"# AD/B747/308 Air Data System 8/2004\n\nApplicability: Model 747-400, 747-400D and 747-400F series aeroplanes identified in Boeing Alert Service Bulletin (ASB) 747-34A2460, Revision 2, dated 14 June 2001.\n\nRequirement: 1. Change the termination of the wires and perform an operational test, according to the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-31-2313, Revision 1, dated 26 September 2002; and/or\n\nNote 1: Requirement 1 is optional for all aeroplanes without three Air Data Computers (ADC) and, if accomplished, extends the compliance for Requirement 2 from 24 months to 72 months.\n\n    2. Modify the ADC system as follows:\n\nRe-route wires associated with ADC overspeed warnings, replace the P1-1 and P3-1 module assemblies in the flight deck with improved module assemblies, install various wires in and between the flight deck and main equipment centre of the aeroplane, and perform a test of the source select module and a system functional test, according to the Accomplishment Instructions of ASB 747- 34A2460, Revision 2.\n\nNote 2: Boeing SB 747-34A2460, Revision 2, refers to Boeing Component Service Bulletins 233U2200-31-01 and 233U2205- 31-01, both dated 20 April 1995, as additional sources for instructions to change the ADC computer source select switch on the P1-1 and P3-1 panels, respectively.\n\n    3. Unless previously accomplished, carry out the following:","sortOrder":1},{"sectionNumber":"For aeroplanes listed in Boeing SB","sectionType":"part","heading":"For aeroplanes listed in Boeing SB","content":"## For aeroplanes listed in Boeing SB\n\n747-31-2179, dated\n\n26 May 1994\n\n747-31-2180, dated\n\n17 March 1994\n\n747-31-2217, dated\n\n19 May 1994\n\n747-31-2217 and\n\n747-31-2178, dated\n\n1 July 1993\n\n747-31-2217 and\n\n747-45-2005, dated\n\n8 February 1990\n\n747-31-2217 and\n\n747-45-2010, dated\n\n17 December 1992\n\n747-31-2217 and\n\n747-31-2163, dated\n\n14 February 1991","sortOrder":2},{"sectionNumber":"Accomplish all actions associated with:","sectionType":"part","heading":"Accomplish all actions associated with:","content":"## Accomplish all actions associated with:\n\nReplacing the three Electronic Flight Information System (EFIS)/Engine Indicating and Crew Alerting System (EICAS) interface units (EIU) in the main equipment centre with improved EIUs and installing new software in six integrated display units (IDU) and three EIUs.\n\nReplacing the three EIUs in the main equipment centre with improved EIUs and installing new software in six IDUs and three EIUs.\n\nInstalling new software in six IDUs and three EIUs.\n\nReplacing three EIUs with improved EIUs and installing new software in six IDUs and three EIUs.\n\nReplacing certain central maintenance computers (CMCs) with improved CMCs, modifying related wiring, and modifying the data loader control panel.\n\nInstalling new software in the CMC.\n\nInstalling new software in six IDUs and three EIUs.","sortOrder":3},{"sectionNumber":"According to the Accomplishment Instruct","sectionType":"part","heading":"According to the Accomplishment Instructions of Boeing SB","content":"## According to the Accomplishment Instructions of Boeing SB\n\n747-31-2179\n\n747-31-2180\n\n747-31-2217\n\n747-31-2178\n\n747-45-2005\n\n747-45-2010\n\n747-31-2163","sortOrder":4}],"analysis":{"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"This version expands the corrective action set beyond a single local wiring or module fix by formally incorporating broader hardware and software modifications and multiple previously-issued Boeing service bulletins as acceptable or required actions. The AD allows alternate/ancillary compliance paths (Requirement 1 optionality that extends compliance times for Requirement 2) and explicitly cross-references component service bulletins for additional instructions (Note 2). Compared with a narrow original intent to correct a single Air Data Computer wiring or overspeed-warning fault, this AD now ties in replacement of EIUs, CMCs, IDU/EIU software updates and associated wiring changes (Requirement 3), thus broadening the scope of work that may be mandatory for some aeroplanes and creating differentiated compliance obligations depending on prior work already accomplished."},"complexity_factors":["Multiple conditional requirements (Requirement 1 is optional for aeroplanes without three ADCs and, if done, extends compliance for Requirement 2 from 24 to 72 months)","Cross-references to multiple Boeing service bulletins: primary ASB 747-34A2460 Rev 2 and SB 747-31-2313 Rev 1","References to multiple prior SBs in Requirement 3 (747-31-2179, 747-31-2180, 747-31-2217, 747-31-2178, 747-45-2005, 747-45-2010, 747-31-2163) with different tasks per SB","Reference to two Boeing Component Service Bulletins (233U2200-31-01 and 233U2205-31-01) in Note 2 for additional instructions","Multiple types of corrective action required: wiring reroute, module replacements (P1-1, P3-1, EIUs, CMCs), software installations in IDUs/EIUs/CMCs, and functional tests","Conditional language “unless previously accomplished” which creates different compliance scopes per aircraft","Interplay between hardware replacement and software update steps (sequence and compatibility risks)","Operational and testing requirements (source select module test, system functional tests) increasing technical execution complexity"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Applies to Boeing 747-400, 747-400D and 747-400F aeroplanes that are listed in Boeing Alert Service Bulletin (ASB) 747-34A2460 Revision 2 (14 June 2001).\n- Requires operators to carry out one or more of the following corrective actions to the Air Data Computer (ADC) and associated systems, in accordance with the Boeing service instructions referenced in the AD:\n  - Requirement 1: Change the termination of certain wires and perform an operational test, following Boeing Special Attention Service Bulletin 747-31-2313 Revision 1 (26 Sep 2002). (This action is optional for aeroplanes that do not have three ADCs; if done it extends the compliance time for Requirement 2 from 24 months to 72 months.)\n  - Requirement 2: Modify the ADC system by re-routing wires related to ADC overspeed warnings; replace the flight-deck P1-1 and P3-1 module assemblies with improved units; install various wires between the flight deck and main equipment centre; test the source-select module; and perform a system functional test — all as set out in ASB 747-34A2460 Revision 2. (Note 2 points to two Boeing Component Service Bulletins for additional instructions on changing the ADC source select switches on the P1-1 and P3-1 panels.)\n  - Requirement 3: If not already done, accomplish additional previously-issued Boeing service bulletin actions: for various SBs listed (747-31-2179; 747-31-2180; 747-31-2217; 747-31-2178; 747-45-2005; 747-45-2010; 747-31-2163) carry out the associated tasks. Those tasks include replacing Electronic Flight Information/EICAS interface units (EIUs) with improved EIUs, installing new software in Integrated Display Units (IDUs) and EIUs, replacing certain Central Maintenance Computers (CMCs) with improved CMCs, wiring modifications, and data loader control panel modifications, depending on which SB applies to the aeroplane.\n\n**Who is affected**\n\n- Aircraft operators/owners of the specified Boeing 747-400 series aeroplanes identified in the ASB list.\n- Maintenance organisations and approved maintenance personnel who must perform the wiring, hardware replacement, software installation and functional tests per the Boeing instructions.\n- The regulator (CASA delegate) enforces compliance under CASR 1998 subregulation 39.1(1).\n\n**Why it matters (purpose claims and practical implications)**\n\n- The AD is issued to correct an unsafe condition related to the Air Data System/ADC and associated overspeed warning logic and display/interface equipment. That is the stated purpose in the AD (see Requirement 1–3 and the background comments in the preamble).\n- Mechanically, compliance requires physical wiring changes, replacement of specific module assemblies (P1-1/P3-1, EIUs, possibly CMCs), software updates to displays and EIUs, and operational/system functional testing.\n\n**Costs, incentives and trade-offs (practical testing of the purpose claim)**\n\n- Who pays: The aircraft operator bears the direct costs (parts, labour, aircraft downtime) of modifications, replacements and testing required by the AD (see Requirements 1–3 and associated Boeing SBs).\n- Who decides: The CASA delegate issues the AD and prescribes the actions; Boeing service bulletins supply the technical steps required to comply (indicated throughout Requirements and Notes).\n- Behaviour changes required: Operators must schedule maintenance events to perform the wiring changes, module replacements and software installations and run the specified tests. If Requirement 1 is done on aircraft without three ADCs, operators gain an extended compliance period for Requirement 2 (24 → 72 months) — this creates an incentive to do Requirement 1 on eligible aircraft to defer the more extensive Requirement 2 work.\n- Implementation risk and logistics: The AD cross-references several Boeing SBs and component SBs (see Note 2 and Requirement 3). That creates coordination needs for parts availability (improved EIUs, CMCs, P1-1/P3-1 modules), validated software images, qualified maintenance providers, and potential aircraft downtime while tests and installations are completed.\n- Compliance burden: Complexity of the retrofit varies by aeroplane depending on which prior SB actions have already been accomplished (Requirement 3 is qualified by “unless previously accomplished”). Different aeroplanes may therefore face different scopes of required work and testing.\n\n**Effects on private choice, markets and safety oversight**\n\n- The AD restricts operator choice in the sense that compliance must follow the technical instructions referenced (Boeing SBs) and be completed within the compliance windows. Operators may choose which compliant path to take where the AD allows options (for example Requirement 1 is optional for certain aeroplanes and affects timing for Requirement 2).\n- The measure requires purchase/installation of improved hardware and software in many cases; that concentrates demand for specific parts and for approved maintenance capability.\n\n**Concrete implementation points to note (section references)**\n\n- Applicability: Boeing ASB 747-34A2460 Revision 2 (14 June 2001).\n- Requirement 1: Boeing Special Attention SB 747-31-2313 Revision 1 (26 Sep 2002) (optional for aeroplanes without three ADCs; compliance-time extension effect on Requirement 2 is stated in Note 1).\n- Requirement 2: ASB 747-34A2460 Revision 2 (wiring re-route, P1-1/P3-1 replacement, install wiring, source-select module test, system functional test). Note 2 points to component SBs 233U2200-31-01 and 233U2205-31-01 (20 Apr 1995) for source-select switch instructions.\n- Requirement 3: References multiple Boeing SBs (747-31-2179; 747-31-2180; 747-31-2217; 747-31-2178; 747-45-2005; 747-45-2010; 747-31-2163) to ensure prior or equivalent EIU/IDU/CMC/software/upgrades are accomplished if not already done.\n\nThis AD is a prescriptive safety measure: it tells operators exactly which hardware, wiring and software changes and tests must be completed (per the Boeing instructions) and ties compliance timing to whether certain optional actions are done."},"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":false,"description":"This AD appears focused on its original purpose: correcting unsafe conditions in the air data system of specific Boeing 747-400 variants. While Requirement 3 incorporates related avionics updates (display systems, maintenance computers), these appear integrally connected to the core air data system modification rather than scope creep. The multiple service bulletins referenced all relate to the same technical system and aircraft variants."},"complexity_factors":["Multiple overlapping requirements with conditional applicability (Requirement 1 is optional but affects compliance timing for Requirement 2)","Extensive cross-referencing to external Boeing documents: 1 Alert Service Bulletin, 1 Special Attention Service Bulletin, 2 Component Service Bulletins, and 7 additional Service Bulletins in Requirement 3","Requirement 3 contains a matrix-style table matching specific aircraft configurations to different combinations of actions and source documents","Nested conditions: 'Unless previously accomplished' qualifier in Requirement 3, and the 24-month vs 72-month compliance extension tied to both Requirement 1 completion and aircraft configuration (presence/absence of three ADCs)","Technical aviation terminology throughout (ADC, EFIS, EICAS, EIU, IDU, CMC, P1-1/P3-1 modules) requiring specialized knowledge to interpret"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) that requires specific repairs or modifications to aircraft.\n\n**What it does:**\nThis directive orders fixes to the **air data system** on certain Boeing 747-400 series aircraft. The air data system collects critical flight information like airspeed, altitude, and temperature — data that pilots rely on to fly safely.\n\n**Who it affects:**\nOwners and operators of **Boeing 747-400, 747-400D, and 747-400F** aircraft that are listed in a specific Boeing service bulletin (ASB 747-34A2460, Revision 2).\n\n**What must be done:**\nOperators must complete one or more of the following actions:\n- **Option 1 (optional):** Rewire and test certain systems. If done, it extends the deadline for the main fix from 24 months to 72 months — but only for planes without three Air Data Computers (ADCs).\n- **Requirement 2 (mandatory):** Modify the ADC system by rerouting wires, replacing control panel modules in the cockpit with improved versions, installing new wiring, and running system tests.\n- **Requirement 3 (mandatory if not already done):** Update various electronic systems including display units, interface units, and maintenance computers — with the exact work depending on which previous service bulletins apply to each specific aircraft.\n\n**Why it matters:**\nUnsafe conditions in the air data system can lead to incorrect speed or altitude readings, which creates serious flight safety risks. This AD ensures these systems meet current safety standards."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-308-air-data-system","history":"/api/acts/ad-b747-308-air-data-system/history","analysis":"/api/acts/ad-b747-308-air-data-system/analysis","conflicts":"/api/acts/ad-b747-308-air-data-system/conflicts","importantCases":"/api/acts/ad-b747-308-air-data-system/important-cases","documents":"/api/acts/ad-b747-308-air-data-system/documents"}}