{"id":"F2006B03022","name":"AD/B747/121 Amdt 1 - Inspection of APU and Cargo Compartment Fire Extinguisher Bottle Cartridges","slug":"ad-b747-121-amdt-1-inspection-of-apu-and-cargo-compartment-fire-extinguisher-bottle-cartridges","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42381,"registerId":"commonwealth-F2006B03022-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/121 Amdt 1 - Inspection of APU and Cargo Compartment Fire Extinguisher Bottle Cartridges","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBoeing 747 Series Aeroplanes\n\nAD/B747/121\n\nAmdt 1\n\n  \n\nInspection of APU and Cargo Compartment Fire Extinguisher Bottle Cartridges\n\n  \n11/93\n\nApplicability: All model 747-400 aircraft identified in Boeing Alert Service Bulletin 747-26A2210 dated 29 October 1992.\n\nRequirement: 1. Visually inspect, in accordance with Boeing Alert Service Bulletin 747-26A2210 dated 29 October 1992, the discharge cartridges (squibs) and electrical connectors installed on each fire extinguisher bottle in the auxiliary power unit, lower cargo and main deck cargo fire extinguishing systems.\n\nNote 1: The operational tests of the discharge cartridges specified in the Accomplishment Instructions of the Service Bulletin are not required to be performed prior to accomplishing the visual inspection.\n\nNote 2: The cross-wiring end-to-end functional checks required by AD/B747/68 Amdt 1 are not obligatory, following performance of the visual inspection, if the inspection is accomplished one discharge cartridge at a time.\n\n2. If any damage is detected during the visual inspection, then prior to further flight replace the damaged item and perform an operational test of the fire bottle discharge cartridge circuit in accordance with Boeing Alert Service Bulletin 747- 26A2210 dated 29 October 1992.\n\nNote: FAA AD 93-09-01 Amdt 39-8568 refers.\n\nCompliance: Unless previously accomplished, prior to 30 November 1993.\n\nBackground: This directive is prompted by reports of bent pins in discharge cartridge cartridges and damaged electrical connectors on some fire extinguisher bottles. These conditions, although being able to prevent the fire bottle discharging, remain undetected by the Discharge Cartridge Circuit Operational Test. (The damage is believed to result from installation or removal of a shunt plug from the cartridge, shunt plugs were installed to protect the cartridge during maintenance.) The one time inspection of the cartridges and electrical connectors, required by this Directive, is intended to ensure the proper discharge of the fire extinguisher bottle in the event of a fire.\n\nAmendment 1 is issued to clarify the requirement to include inspection of both the lower and main deck cargo fire extinguisher systems.","sortOrder":0}],"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 clarifies and explicitly includes inspection of both the lower and main deck cargo fire extinguisher systems; it therefore expands the directive's stated scope compared with the original text by making those systems explicit (Amendment 1)."},"complexity_factors":["Technical specificity: inspection targets squibs and electrical connectors and must follow Boeing Alert Service Bulletin 747-26A2210 (Requirement 1).","Conditional actions: operational test required only if damage is found and before further flight (Requirement 2); Note 1 excludes pre-inspection operational tests.","Interaction with prior AD: Note 2 references AD/B747/68 Amdt 1 for cross-wiring checks and limits that requirement when inspecting one cartridge at a time.","Applicability constraint: applies only to model 747-400 aircraft identified in the service bulletin (Applicability).","Compliance timing: fixed deadline imposes a one‑time scheduling and resource cost prior to 30 November 1993 (Compliance).","Implementation burden: physical access, visual inspection skills, and potential immediate replacement/testing create direct maintenance costs and aircraft downtime.","Dependence on external document: procedural detail and test methods are delegated to the Boeing service bulletin rather than set out fully in the directive.","Scope clarification: Amendment 1 explicitly adds both lower and main deck cargo extinguisher systems to the inspection requirement (Amendment 1)."],"plain_english_summary":"This airworthiness directive requires a one‑time visual inspection of the discharge cartridges (squibs) and electrical connectors on APU, lower cargo and main deck cargo fire extinguisher bottles of specified Boeing 747-400 aircraft, carried out per Boeing Alert Service Bulletin 747-26A2210. If damage is found, the defective item must be replaced and an operational test of the discharge circuit done before further flight. It affects operators of the identified 747-400s and matters because hidden bent pins or damaged connectors can stop a fire bottle from discharging despite passing circuit tests."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment is purely clarifying — it explicitly includes both lower and main deck cargo systems where the original may have been ambiguous. The scope remains tightly focused on the original safety issue: inspecting fire extinguisher discharge cartridges on 747-400 aircraft."},"complexity_factors":["Single, specific technical requirement (visual inspection of two component types)","Only 2 main operative paragraphs with clear conditional logic (if damage found → replace and test)","2 helpful notes that reduce rather than add complexity","No defined terms section — technical terms explained in context","Clear compliance deadline with single exception (unless previously accomplished)","Short document (approximately 250 words)","Single cross-reference to related directive (AD/B747/68 Amdt 1) and FAA equivalent"],"plain_english_summary":"This directive orders operators of affected Boeing 747-400s to perform a visual inspection of discharge cartridges (\"squibs\") and their electrical connectors on fire-extinguisher bottles in the APU and cargo compartments after reports of bent pins/damaged connectors that can prevent extinguisher discharge. Damaged parts must be replaced and the system tested before flight. Compliance (per the Boeing service bulletin) was required before 30 Nov 1993; Amendment 1 clarifies both lower and main-deck cargo systems are included."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-121-amdt-1-inspection-of-apu-and-cargo-compartment-fire-extinguisher-bottle-cartridges","history":"/api/acts/ad-b747-121-amdt-1-inspection-of-apu-and-cargo-compartment-fire-extinguisher-bottle-cartridges/history","analysis":"/api/acts/ad-b747-121-amdt-1-inspection-of-apu-and-cargo-compartment-fire-extinguisher-bottle-cartridges/analysis","conflicts":"/api/acts/ad-b747-121-amdt-1-inspection-of-apu-and-cargo-compartment-fire-extinguisher-bottle-cartridges/conflicts","importantCases":"/api/acts/ad-b747-121-amdt-1-inspection-of-apu-and-cargo-compartment-fire-extinguisher-bottle-cartridges/important-cases","documents":"/api/acts/ad-b747-121-amdt-1-inspection-of-apu-and-cargo-compartment-fire-extinguisher-bottle-cartridges/documents"}}