{"id":"F2006B03172","name":"AD/B747/276 - Thrust Reverser Modifications and Tests","slug":"ad-b747-276-thrust-reverser-modifications-and-tests","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42544,"registerId":"commonwealth-F2006B03172-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 747 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B747/276 Thrust Reverser Modification","sectionType":"part","heading":"AD/B747/276 Thrust Reverser Modifications and Tests 7/2002","content":"# AD/B747/276 Thrust Reverser Modifications and Tests 7/2002\n\nApplicability: Model 747-200 and 300 series aeroplanes powered by General Electric Model CF6- 80C2 series engines with Power Management Control engine controls.\n\nRequirement: 1. Install an actuation system lock bracket and fastening hardware to each thrust reverser in accordance with the Accomplishment Instructions of Lockheed Martin Service Bulletin 78-1007, Revision 1, dated 18 March, 1997, or Middle River Aircraft Systems Service Bulletin 78-1007, Revision 2, dated 10 March, 1998.\n\n    2. Install an actuation system lock (also called an electro- mechanical lock or electro-mechanical brake) on each thrust reverser in accordance with the Accomplishment Instructions of Lockheed Martin Service Bulletin 78-1020, Revision 2, dated 20 March, 1997, or Middle River Aircraft Systems Service Bulletin 78-1020, Revision 3, dated 16 March, 1998.\n\n    3. Carry out thrust reverser wiring modifications of the wings, strut, and fuselage, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-78-2144, Revision 1, dated 11 April, 1996.\n    4. Carry out a functional test to detect discrepancies of the centre drive unit (CDU) cone brake and actuation system lock on each thrust reverser, in accordance with Appendix 1 of FAA AD 2000-15-04 amendment 39-11833.\n    5. Correct any discrepancy detected when carrying out the requirements of Requirement 4, and repeat the functional test of that repair, in accordance with the procedures described in approved maintenance data.\n    6. Repeat Requirement 4 functional tests.\n\nNote: FAA AD 2000-15-04 amendment 39-11833 refers that supersedes FAA AD 99- 15-08 amendment 39-11227 that supersedes FAA AD 95-06-01 amendment 39-9171.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific unsafe condition in thrust reverser systems on particular Boeing 747 variants. The references to superseded FAA directives show an evolution of the technical solution over time, but the regulatory scope remains targeted at the same safety issue and aircraft population."},"complexity_factors":["Multiple technical service bulletins referenced (4 different documents from Lockheed Martin, Middle River Aircraft Systems, and Boeing)","Nested references to superseded FAA ADs (three layers deep: 2000-15-04 supersedes 99-15-08 which supersedes 95-06-01)","Specific model and engine applicability restrictions (747-200/300 series with CF6-80C2 engines only)","Cross-references to external 'approved maintenance data' for repair procedures without specifying content","Ongoing compliance obligation (Requirement 6 mandates repeated testing without specifying intervals)"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of certain Boeing 747-200/300 aircraft with GE CF6‑80C2 engines to carry out safety modifications and ongoing functional testing of thrust reversers — installing locks/brakes, rewiring systems, testing centre drive unit brakes/locks, repairing defects and repeating tests. \n\nIt targets operators of these older wide‑body jets (including cargo carriers) to prevent uncommanded in‑flight thrust reverser deployment, a critical hazard that has caused fatal accidents such as Lauda Air Flight 004."},"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":5,"scope_assessment":{"changed":false,"description":"This AD remains focused on retrofitting mechanical locks, wiring changes and testing of thrust reverser systems on the specified 747-200/300 airframes with CF6-80C2 engines. The version quoted cross-references later revisions of service bulletins and a later FAA AD amendment, but does not broaden the affected aircraft types or add unrelated requirements. In other words, it preserves the original narrow safety purpose (modify and test thrust reverser hardware/systems) rather than expanding scope beyond that purpose."},"complexity_factors":["Multiple external documents referenced: Lockheed Martin SBs (78-1007 rev 1; 78-1020 rev 2), Middle River SBs (78-1007 rev 2; 78-1020 rev 3), Boeing SB 747-78-2144 rev 1, and FAA AD 2000-15-04 (Appendix 1).","Cross-reference to superseding FAA ADs (the Note lists a chain of FAA ADs), requiring readers to follow a history of amendments for full context.","Six discrete required actions with sequential logic (installations → wiring mods → functional test → corrective action → repeat tests).","Reliance on 'approved maintenance data' for corrective procedures, introducing a delegated discretion point (what constitutes approved data).","Lack of explicit timing/interval information in the excerpt (compliance deadlines likely in another section), which increases implementation ambiguity.","Multiple acceptable service bulletin revisions (operators must choose the correct edition and ensure compatibility), increasing administrative checking.","Technical specificity (thrust reverser CDU cone brake and electro-mechanical locks) requires specialised maintenance knowledge and parts availability."],"plain_english_summary":"**What this instrument does (plain English)**\n\n- This Airworthiness Directive (AD) tells operators of certain Boeing 747-200 and 747-300 aeroplanes what mandatory hardware changes and tests they must carry out on the thrust reverser systems for safety reasons.\n\n- It applies only to Boeing 747-200 and 747-300 aeroplanes that are fitted with General Electric CF6-80C2 series engines using Power Management Control (PMC) engine controls (Applicability). \n\n- The AD requires six specific actions (Requirement 1–6):\n  - Install an actuation system lock bracket and associated fastenings on each thrust reverser, following the detailed steps in Lockheed Martin Service Bulletin 78-1007 Revision 1 or Middle River Aircraft Systems Service Bulletin 78-1007 Revision 2 (Requirement 1).\n  - Install an electro-mechanical actuation system lock (also called an electro-mechanical brake) on each thrust reverser, following Lockheed Martin Service Bulletin 78-1020 Revision 2 or Middle River Service Bulletin 78-1020 Revision 3 (Requirement 2).\n  - Modify thrust reverser wiring in the wing, strut and fuselage as described in Boeing Service Bulletin 747-78-2144 Revision 1 (Requirement 3).\n  - Perform a functional test to check the centre drive unit (CDU) cone brake and the actuation system lock on each thrust reverser, following Appendix 1 of FAA AD 2000-15-04 (Requirement 4).\n  - If any discrepancy is found in that functional test, correct it using approved maintenance procedures and re-run the test for that repair (Requirement 5).\n  - Repeat the Requirement 4 functional tests (Requirement 6). The AD cross-references FAA AD material and several service bulletins for the detailed procedures (Note).\n\n**Who is affected and who pays**\n\n- Affected parties: aircraft operators, aircraft maintenance organisations, and owners of the specific 747-200/300 airframes with the CF6-80C2 engines and PMC controls.\n- Who pays: the aircraft operators (or their lessors) pay for parts, labour, and aircraft downtime needed to do the hardware installs, wiring changes and tests. Maintenance organisations perform the work and must follow the approved service information.\n\n**How it works mechanically**\n\n- The AD does not itself give step-by-step instructions; instead it makes compliance mandatory by requiring the use of the named service bulletins and the FAA AD appendix. The service bulletins specify exactly how to fit brackets, locks, and make wiring changes; the FAA AD appendix sets out the functional test procedures and acceptance criteria.\n- If tests find faults, operators must fix them per approved maintenance data, then re-test until the test passes (Requirements 4–5).\n\n**Why the AD exists (stated purpose) and how that trades off with costs**\n\n- The AD states (by reference to the FAA AD and service bulletins) that the actions are necessary to correct an unsafe condition affecting the thrust reverser actuation and braking systems. That is the stated safety purpose.\n- Trade-offs and implementation considerations:\n  - Costs: purchase and fitment of lock brackets and electro-mechanical locks, wiring work, testing labour, and aircraft out-of-service time. These are concentrated costs on affected operators (Requirements 1–3, 4–6).\n  - Benefit claimed: mitigation of a thrust-reverser related unsafe condition (misdeployment or failure modes identified in the underlying FAA AD/service bulletins). The AD itself does not quantify economic benefits; it mandates the technical fixes and tests (Requirements and Note).\n  - Compliance mechanics: the AD depends on multiple external technical documents (several service bulletins and an FAA AD) that maintenance personnel must obtain and follow exactly to show compliance (Requirements 1–4, Note).\n  - Operational risk and implementation: downtime scheduling, availability of parts, and approved maintenance data quality determine how quickly operators can comply. If repairs are required after testing, additional work and downtime will be necessary (Requirement 5).\n  - Behavioural effect: operators must retrofit and test older airframes; aftermarket suppliers and maintenance organisations will perform the work (Requirements 1–3, 4–6).\n\n**Concrete reference to the text**\n\n- Mandatory installs: Requirement 1 (bracket) and Requirement 2 (electro-mechanical lock).\n- Wiring changes: Requirement 3.\n- Testing, correction and repetition: Requirements 4–6 and the Note referring to FAA AD 2000-15-04 and prior FAA ADs.\n\n**Practical note**\n\n- The AD uses specific service bulletin revisions and an FAA AD appendix for the detailed steps and test criteria. Operators must have and use those documents to demonstrate compliance. The AD does not set out timing or intervals in the text shown here — the AD’s compliance section (not reproduced) typically sets deadlines; operators should consult the full AD text and the referenced service bulletins/FAA AD for compliance time limits and precise procedures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-276-thrust-reverser-modifications-and-tests","history":"/api/acts/ad-b747-276-thrust-reverser-modifications-and-tests/history","analysis":"/api/acts/ad-b747-276-thrust-reverser-modifications-and-tests/analysis","conflicts":"/api/acts/ad-b747-276-thrust-reverser-modifications-and-tests/conflicts","importantCases":"/api/acts/ad-b747-276-thrust-reverser-modifications-and-tests/important-cases","documents":"/api/acts/ad-b747-276-thrust-reverser-modifications-and-tests/documents"}}