{"id":"F2007L04265","name":"AD/AB139/2 - Engine Fire Extinguisher Bottles","slug":"ad-ab139-2-engine-fire-extinguisher-bottles","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":70496,"registerId":"commonwealth-F2007L04265-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Agusta AB139 and AW139 Series Helicopter","sectionType":"division","heading":"Agusta AB139 and AW139 Series Helicopters","content":"### Agusta AB139 and AW139 Series Helicopters\n\n| AD/AB139/2 | Engine Fire Extinguisher Bottles | 13/2007 DM |\n| ---------- | -------------------------------- | ---------- |\n\n| Applicability: | AB139 model helicopters with serial numbers (S/N) 31005 to 31054 except 31007 and AW139 model helicopters with S/N 31055 to 31067, 31070 and 31071.                                                                                                                                                          |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | 1. If not previously accomplished, verify the correct installation of electrical receptacles/connectors on the fire extinguisher bottles in accordance with Agusta Bollettino Tecnico (BT) 139-085 dated 18 May 2007 or later revision approved by the Italian Ente Nazionale per l’Aviazione Civile (ENAC). |\n|                | 2. If, as a result of the Requirement 1 verification, any discrepancy is detected with the fire bottle electrical connector installation, replace the defective fire bottle in accordance with BT 139-085 or later revision approved by the ENAC.                                                            |\n|                | Note: ENAC AD 2007-227 Revision 1 refers.                                                                                                                                                                                                                                                                    |\n| Compliance:    | For Requirement 1 - Within 30 days after the effective date of this Directive.                                                                                                                                                                                                                               |\n|                | For Requirement 2 - Before further flight after the Requirement 1 verification inspection.                                                                                                                                                                                                                   |\n|                | This Airworthiness Directive becomes effective on 10 November 2007.                                                                                                                                                                                                                                          |\n| Background:    | The ENAC has advised that during an installation of a fire extinguisher bottle part number 3G2620V00131 on a new helicopter, it was found that the connectors on the bottle were swapped between engines one and two.                                                                                        |\n|                | This condition, if not corrected, might cause the extinguishing agent to discharge into the incorrect engine when the system is activated. This Directive requires the fire bottles to be inspected and, if necessary, replaced.                                                                             |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n29 October 2007","sortOrder":0},{"sectionNumber":"AD/AB139/2","sectionType":"part","heading":"AD/AB139/2","content":"## AD/AB139/2","sortOrder":1},{"sectionNumber":"Engine Fire Extinguisher Bottles","sectionType":"part","heading":"Engine Fire Extinguisher Bottles","content":"## Engine Fire Extinguisher Bottles","sortOrder":2},{"sectionNumber":"13/2007 DM","sectionType":"part","heading":"13/2007 DM","content":"## 13/2007 DM","sortOrder":3}],"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":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific manufacturing defect in a specific helicopter model. The scope remains tightly focused on the identified safety risk (swapped fire bottle connectors) and has not expanded beyond this original purpose."},"complexity_factors":["Single, discrete safety issue with clear mechanical remedy","Only 2 substantive requirements with straightforward conditional logic (if-then)","Limited applicability — specific serial number ranges explicitly listed","No nested definitions, cross-references to other legislation, or interpretive provisions","References only one external technical document (manufacturer bulletin BT 139-085)","Total length: approximately 250 words of operative text"],"plain_english_summary":"This AD requires owners/operators of certain Agusta AB139/AW139 helicopters to inspect engine fire-extinguisher bottle electrical connectors because some were swapped between Engine 1 and Engine 2 during manufacture. If connectors are incorrect, bottles must be replaced before further flight. It affects the specified serial-numbered helicopters and seeks to ensure extinguishers discharge to the correct engine, preventing ineffective fire suppression and possible catastrophic loss."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This directive addresses a single, narrowly defined installation defect (swapped electrical connectors on engine fire‑extinguisher bottles). The measures—inspect and replace—align directly with that safety objective. There is no expansion beyond the original purpose: it does not add unrelated requirements, broaden affected aircraft beyond specific serial numbers, or create ongoing monitoring obligations. It simply mandates corrective action and references the manufacturer's technical bulletin and ENAC approvals for execution."},"complexity_factors":["Narrow applicability: specific serial number ranges with two serials excluded","Two-step requirement structure (inspect, then replace if defect found)","Single external technical reference: Agusta Bollettino Tecnico (BT) 139-085 (18 May 2007) or later ENAC‑approved revision","Short, fixed compliance time (30 days) and immediate replacement before further flight if required","Cross-reference to ENAC AD 2007-227 Revision 1 for context","No layered exceptions or multiple conditional branches"],"plain_english_summary":"**What this directive does (mechanics)\n\n- Applies to: Agusta AB139 helicopters S/N 31005–31054 (except 31007) and AW139 helicopters S/N 31055–31067, 31070 and 31071 (\"Applicability\").\n\n- The directive requires two actions:\n  - Requirement 1: Check that the electrical receptacles/connectors on the engine fire‑extinguisher bottles are installed correctly, using Agusta Bollettino Tecnico (BT) 139‑085 dated 18 May 2007 (or a later revision approved by the Italian aviation authority ENAC).\n  - Requirement 2: If the inspection finds any connector installation discrepancy, replace the defective fire bottle in accordance with BT 139‑085 (or later ENAC‑approved revision).\n\n- Timing (\"Compliance\"): Inspectors/operators must perform Requirement 1 within 30 days of the directive becoming effective. If a defective bottle is found, it must be replaced before the helicopter flies again. The directive became effective 10 November 2007.\n\n- Source of the problem (\"Background\"): During installation of a fire bottle (part number 3G2620V00131) on a new helicopter, the connectors were found swapped between engines one and two. If uncorrected, the extinguishing agent could discharge into the wrong engine when triggered.\n\n\nWho this affects and who pays\n\n- Directly affected: Operators and owners of the specific AB139/AW139 helicopters listed by serial number.\n- Responsible party: The operator or maintenance organisation must carry out the inspection and, if required, the replacement. The operator pays for labour, spare bottles and any associated downtime.\n- Authority/decision maker: The directive bases the technical procedure on Agusta BT 139‑085 and requires approval of later revisions by ENAC (the Italian civil aviation authority). The Civil Aviation Safety Authority (CASA) delegate issued the directive for Australian airworthiness compliance.\n\n\nWhy it matters (safety and operational mechanics)\n\n- Safety: The defect can cause the fire‑suppression agent to go into the wrong engine, which would render the intended engine fire suppression ineffective and could create additional hazards.\n- Operational consequence: If a discrepancy is detected, the helicopter must be grounded until the defective bottle is replaced (replacement required \"before further flight\"), creating potential aircraft downtime.\n\n\nCosts, incentives, and implementation considerations\n\n- Financial cost: Operators bear inspection costs and replacement costs for defective bottles. If many helicopters are affected, aggregate cost could be material to a fleet.\n- Downtime and supply risk: Replacement must occur before flight, so parts availability and maintenance scheduling determine how long an aircraft will be out of service.\n- Compliance burden: The inspection is a one‑time mandated check (within 30 days) and replacement only if defects are found. The work references a manufacturer technical bulletin (BT 139‑085), so maintainers must follow that document.\n- Regulatory dependence: The directive cross‑references ENAC approval for later revisions of the technical bulletin and notes ENAC AD 2007‑227 Revision 1. That means later technical changes are effective only when ENAC approves them.\n- Concentrated benefits and diffuse costs: The immediate safety benefit is concentrated (reduced risk of failed engine fire suppression on the affected helicopters). Costs are concentrated on the owners/operators of the listed serial numbers.\n\n\nTrade‑offs and implementation risk\n\n- Trade‑off: A short inspection window (30 days) reduces safety exposure quickly but increases near‑term maintenance demand and possible grounding. Operators must prioritise affected aircraft.\n- Implementation risks: If BT 139‑085 is ambiguous or if replacement parts are scarce, compliance could be delayed. Reliance on ENAC for approving later revisions introduces cross‑jurisdictional dependency for technical updates.\n\n\nWhere to find the technical steps\n\n- The directive instructs maintainers to follow Agusta BT 139‑085 dated 18 May 2007 (or later ENAC‑approved revision) for both verification and replacement procedures (see \"Requirement\" and the \"Note\" referring to ENAC AD 2007‑227 Revision 1).\n\n\nBottom line: This is a targeted, safety‑driven directive requiring a one‑time inspection of specified AB139/AW139 helicopters' engine fire‑bottle electrical connectors within 30 days and replacement of any miswired bottles before flight. The operator bears the direct costs and downtime; the procedures are those set out in Agusta's technical bulletin as approved by ENAC."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ab139-2-engine-fire-extinguisher-bottles","history":"/api/acts/ad-ab139-2-engine-fire-extinguisher-bottles/history","analysis":"/api/acts/ad-ab139-2-engine-fire-extinguisher-bottles/analysis","conflicts":"/api/acts/ad-ab139-2-engine-fire-extinguisher-bottles/conflicts","importantCases":"/api/acts/ad-ab139-2-engine-fire-extinguisher-bottles/important-cases","documents":"/api/acts/ad-ab139-2-engine-fire-extinguisher-bottles/documents"}}