{"id":"F2008L04559","name":"AD/B747/387 - AN-26 Insulation Blankets","slug":"ad-b747-387-an-26-insulation-blankets","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":120858,"registerId":"commonwealth-F2008L04559-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 747 Series Aeroplanes","sectionType":"division","heading":"Boeing 747 Series Aeroplanes","content":"### Boeing 747 Series Aeroplanes\n\n| AD/B747/387 | AN-26 Insulation Blankets | 1/2009 |\n| ----------- | ------------------------- | ------ |\n\n| Applicability: | Boeing 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F,747-300, 747SR, and 747SP series aircraft, serial numbers as defined in Boeing Special Attention Service Bulletin 747-25-3429, and Boeing 747-400 series aircraft, serial numbers 23719, 23720, 23814, 23816, 23817, 23818, 23819, 23820, 23999, 24061, and 24062.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Either:a. Remove all insulation blankets from the pressurized areas of the fuselage and install new insulation blankets using a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. The new insulation blankets must comply with 14 Code of Federal Regulations (CFR) 25.856(a). The areas where the affected insulation blankets are installed include, but are not limited to, the following areas:(i) Crown area of the airplane;(ii) Areas behind flight deck panels and circuit breaker panels;(iii) Areas behind sidewalls, lavatories, closets, and galleys;(iv) Cargo compartment areas;(v) Air ducting;(vi) Waste and water tubing; and(vii) Areas attached to the underside of floor panels. ; orb. Remove the existing fuselage insulation blankets and install new insulation blankets, in accordance with the Accomplishment Instructions of the Boeing Special Attention Service Bulletin747-25-3429.However, these actions are not required for any insulation blanket that is determined not to be constructed of Orcon Orcofilm AN-26, using an identification method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA or in accordance with Appendix A of Boeing Special Attention Service Bulletin 747-25-3429. |\n\n|             | 2. No person may install any insulation blanket constructed of AN-26 as a replacement unless it has been modified to comply with 14 CFR 25.856(a).Note 1: Insulation material that is part-marked with a date of manufacture indicating that it was manufactured before July 1981 or after December 1988 is not constructed of AN-26.Note 2: FAA AD 2008-23-09 refers.                                                                                                                                                                                                                                                                     |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Compliance: | 1. Within 96 months after the effective date of this Airworthiness Directive.2. After the effective date of this Airworthiness Directive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |\n|             | This Airworthiness Directive becomes effective on 15 January 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| Background: | This Airworthiness Directive results from reports of in-flight and ground fires on certain airplanes manufactured with insulation blankets covered with a specific polyethyleneteraphthalate (PET), ORCON Orcofilm AN-26 (all variants, including AN-26, AN-26A, and AN-26B), which may contribute to the spread of a fire when ignition occurs from sources such as electrical arcing. We are issuing this Airworthiness Directive to ensure that insulation blankets constructed of AN-26 are removed from the fuselage. Such insulation blankets could ignite and propagate a fire that is the result of electrical arcing or sparking. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n24 November 2008","sortOrder":0},{"sectionNumber":"AD/B747/387","sectionType":"part","heading":"AD/B747/387","content":"## AD/B747/387","sortOrder":1},{"sectionNumber":"AN-26 Insulation Blankets","sectionType":"part","heading":"AN-26 Insulation Blankets","content":"## AN-26 Insulation Blankets","sortOrder":2},{"sectionNumber":"1/2009","sectionType":"part","heading":"1/2009","content":"## 1/2009","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with focused scope. It addresses a specific safety defect (AN-26 insulation fire risk) in specific aircraft models. The scope remains tightly constrained to the identified safety issue without expansion into unrelated operational or maintenance areas."},"complexity_factors":["Multiple compliance pathways (two alternative methods in Requirement 1, plus an exception)","Specific serial number applicability lists requiring cross-referencing with Boeing documentation","Reference to external US regulations (14 CFR 25.856(a)) and FAA approval requirements","Geographic scope limitations (areas listed with 'but not limited to' language creating interpretive uncertainty)","Nested exception structure: main requirement → alternative compliance → exception for non-AN-26 materials → automatic exclusion based on date markings","Cross-reference to Boeing Special Attention Service Bulletin 747-25-3429 for technical implementation details"],"plain_english_summary":"This AD requires removal and replacement of Orcon Orcofilm AN-26 PET insulation from pressurized areas of affected Boeing 747s because the material can ignite and propagate fire from electrical arcing. Operators must install FAA‑approved, less‑flammable insulation or follow Boeing service instructions; a blanket can be left if proven not to be AN‑26. Compliance deadline: 96 months from 15 Jan 2009 (by Jan 2017)."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The directive sets a defined applicability (specific 747 variants and serial numbers) and prescribes two alternative compliance methods plus a prohibition on installing unmodified AN-26. The text does not indicate any amendment or narrowing/expansion to that applicability within the instrument itself; therefore scope has not been changed from the document's stated requirements."},"complexity_factors":["Cross-reference to FAA approval authority: replacement method must be \"approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA\" (Requirement 1a/b) — creates a reliance on an external approval process.","Two alternative compliance routes: either an FAA-approved installation method ensuring 14 CFR 25.856(a) compliance, or following Boeing Special Attention Service Bulletin 747-25-3429 (Requirement 1a/1b) — adds procedural complexity.","Material identification requirement: blankets must be identified as AN-26 or not using an FAA-approved method or Appendix A of the Boeing service bulletin (Requirement 1b) — creates inspection and recordkeeping burdens.","Prohibition on installation of unmodified AN-26 material unless altered to meet 14 CFR 25.856(a) (Requirement 2) — affects supply chain and parts procurement.","Applicability scope: multiple 747 variants and specific serial numbers listed (Applicability) — demands fleet-level tracking and targeted action.","Temporal compliance window: 96-month compliance period (Compliance 1) — spreads implementation costs but requires long-term planning.","Technical standard linkage: requirement to meet 14 CFR 25.856(a) (Requirement 1a/2) ties the AD to a separate flammability standard, requiring technical assessment or modification of materials.","Notes and cross-references: Part-marking date exceptions and reference to FAA AD 2008-23-09 (Requirement 2, Notes) add interpretive detail operators must apply."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of specified Boeing 747 series aircraft to identify and, if made of ORCON Orcofilm AN-26, remove and replace fuselage insulation blankets within 96 months (or show they are not AN-26 by an approved method). It also prohibits installing AN-26 material as a replacement unless modified to meet 14 CFR 25.856(a). It affects aircraft operators, maintenance organisations and parts suppliers because of inspection, removal and replacement obligations and parts restrictions."},"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-b747-387-an-26-insulation-blankets","history":"/api/acts/ad-b747-387-an-26-insulation-blankets/history","analysis":"/api/acts/ad-b747-387-an-26-insulation-blankets/analysis","conflicts":"/api/acts/ad-b747-387-an-26-insulation-blankets/conflicts","importantCases":"/api/acts/ad-b747-387-an-26-insulation-blankets/important-cases","documents":"/api/acts/ad-b747-387-an-26-insulation-blankets/documents"}}