{"id":"F2006B03321","name":"AD/B767/144 - Warning Electronics Unit","slug":"ad-b767-144-warning-electronics-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42758,"registerId":"commonwealth-F2006B03321-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 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.\n\n![](image.001.png)\n\nBoeing 767 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B767/144 Warning Electronics Unit 8/2","sectionType":"part","heading":"AD/B767/144 Warning Electronics Unit 8/2001","content":"# AD/B767/144 Warning Electronics Unit 8/2001\n\nDM\n\nApplicability: Model 767-200 -300 and -300F series aeroplanes, line numbers 668 through 723 inclusive, equipped with a warning electronics unit (WEU) power supply Part Number (P/N) 285T0035-201.\n\nRequirement: 1. If not previously accomplished in accordance with AD/B767/113 Requirement 1, check the status page of the engine indication and crew alerting system (EICAS) for any WEU failure; and perform Work Instructions in Section 3, Part 1 of Boeing Service Bulletin (SB) 767-31-0106 Revision 1 dated 17 December 1998 or Revision 2 dated 18 November 1999 to detect loss of any visual, aural, or tactile alert.\n\n    2. If a WEU failure or loss of any visual, aural, or tactile alert is not detected.\n\n    Repeat the Requirement 1 EICAS status page check.\n\n    b. Repeat the Requirement 1 Work Instructions.\n\nNote 1: The EICAS status page check and performance of the Work Instructions in Section 3, Part 1 of the Service Bulletin are maintenance functions that require an aircraft log book entry and maintenance release prior to flight.\n\n    3. If any failure of the WEU, or the loss of any visual, aural, or tactile alert is detected during any Requirement 1, 2.a or 2.b test replace the power supplies with new, modified, or serviceable power supplies having P/N 285T0035-202 Mod A, P/N 285T0035-9, P/N 285T0035-10, or P/N 285T0035-11, in accordance with SB 767-31-0106, Revision 2.\n\n    4. Replace WEU power supplies having P/N 285T0035-201, with new or modified power supplies having P/N 285T0035-202 Mod A; or new, modified, or serviceable power supplies having P/N 285T0035-9, P/N 285T0035-10, or\n\nP/N 285T0035-11; in accordance with SB 767-31-0106, Revision 2.","sortOrder":1},{"sectionNumber":"Boeing 767 Series Aeroplanes","sectionType":"part","heading":"Boeing 767 Series Aeroplanes","content":"## Boeing 767 Series Aeroplanes\n\nAD/B767/144 (Continued)\n\nReplacement of the WEU power supplies with new or modified power supplies having P/N 285T0035-202 Mod A, in accordance with SB 767-31-0106 Revision 1, is an acceptable means of compliance if carried out prior to the effective date of this Directive.\n\n    5. WEU power supply P/N 285T0035-201 may not be installed on any aeroplane as a replacement part.\n\nNote 2: FAA AD 2001-11-08 Amdt 39-12250 refers.\n\nCompliance: For Requirement 1 - Initially, within 15 days of the effective date of this Directive and thereafter in accordance with Requirements 2.a and 2.b.\n\nFor Requirement 2.a - Before each flight until either Requirement 3 or 4 is accomplished.\n\nFor Requirement 2.b - At intervals not to exceed every “A” check or 45 days, whichever occurs first until either Requirement 3 or 4 is accomplished.\n\nFor Requirement 3 - Before further flight. For Requirement 4 \\- Before 16 July 2002.\n\nFor Requirement 5 - As of the effective date of this Directive. This Airworthiness Directive becomes effective on 27 June 2001.\n\nBackground: The Federal Aviation Administration received a report advising that during a production test flight of a Model 747-400 series aeroplane the flight test crew noticed a power supply failure on the status page of the EICAS. Investigation revealed the automatic bench test procedure for the modular avionics warning electronic assembly (MAWEA) overstressed the 5.7 volt over-voltage clamp circuit which resulted in failure of the circuit to protect the warning cards in the MAWEA.\n\nA slow failure of the MAWEA power supply could result in the gradual degradation of available visual, aural and tactile alerts, which could result in flight crew not being aware of and not taking immediate or appropriate action, in the event of an unsafe condition occurring.\n\nThe WEU power supply units on some Boeing 767-200 and -300 series aeroplanes are identical to those on the MAWEA on the affected Model 747-400 aeroplanes. Therefore, all of these aeroplanes may be subject to the same unsafe condition.","sortOrder":2}],"analysis":{"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":4,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It targets a specific safety defect in a specific aircraft type with specific part numbers. The directive does not expand beyond its original purpose of addressing the WEU power supply failure risk identified in the background section."},"complexity_factors":["Multiple conditional requirements with nested logic (Requirements 1-5 with interdependencies)","Cross-references to external technical documents (Boeing Service Bulletin 767-31-0106, Revision 1 and 2)","Specific part numbers (P/N 285T0035-201, -202 Mod A, -9, -10, -11) that must be tracked precisely","Variable compliance timelines depending on which requirement path is followed (15 days, before each flight, every 45 days/A check, before July 16 2002)","Reference to prior directive AD/B767/113 with partial grandfathering clause for previous compliance","Technical aviation terminology requiring domain knowledge (EICAS, WEU, MAWEA, A check, maintenance release)"],"plain_english_summary":"A safety order for certain Boeing 767-200/-300 series (line numbers 668–723) fixes a faulty Warning Electronics Unit (P/N 285T0035-201) that can silently degrade and disable cockpit warnings. It requires immediate and ongoing checks, daily preflight and periodic maintenance monitoring, bans reinstallation of the part, and mandates replacement with an improved unit by July 16, 2002. This prevents pilots losing critical alerting capability."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This Directive supersedes AD/B767/113 and tightens scope by mandating repetitive EICAS checks and specific corrective action: replacing WEU power supply P/N 285T0035-201 with listed alternative P/Ns, banning installation of P/N 285T0035-201, and setting a firm replacement deadline (before 16 July 2002). It also narrows applicability to line numbers 668–723 and cross-references Boeing SB 767-31-0106 (Revs 1/2) and FAA AD 2001-11-08 as the compliance pathway."},"complexity_factors":["Technical specificity: multiple part numbers (285T0035-201, -202 Mod A, -9, -10, -11) and precise line-numbered applicability (668–723)","Conditional, repetitive compliance: initial 15‑day check, pre‑flight repeats until replacement, and interval checks at each “A” check or 45 days","Multiple compliance deadlines and terminating action (before 16 July 2002 for full replacement)","Cross-references to Boeing Service Bulletin 767-31-0106 (Revisions 1 and 2) and prior AD (AD/B767/113) for procedures and acceptable methods","Operational constraints: maintenance log book entry and maintenance release required prior to flight when tests are performed","Prohibition on reinstalling the old part as of the effective date (practical impact on spares management)"],"plain_english_summary":"This Airworthiness Directive requires operators of certain Boeing 767-200/-300 aeroplanes (line numbers 668–723) fitted with WEU power supply P/N 285T0035-201 to perform repeated EICAS status checks and maintenance tests, replace that power supply with specified alternative P/Ns if failures are detected (or by a set deadline), and prohibits reinstalling P/N 285T0035-201. CASA enforces the rule; aircraft operators must perform, log and certify the checks, bear inspection and replacement costs, and may be grounded until defects are fixed."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b767-144-warning-electronics-unit","history":"/api/acts/ad-b767-144-warning-electronics-unit/history","analysis":"/api/acts/ad-b767-144-warning-electronics-unit/analysis","conflicts":"/api/acts/ad-b767-144-warning-electronics-unit/conflicts","importantCases":"/api/acts/ad-b767-144-warning-electronics-unit/important-cases","documents":"/api/acts/ad-b767-144-warning-electronics-unit/documents"}}