{"id":"F2009L02648","name":"AD/A109/63 - Battery Bus Circuit Breaker","slug":"ad-a109-63-battery-bus-circuit-breaker","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":79679,"registerId":"commonwealth-F2009L02648-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Agusta A109 Series Helicopters","sectionType":"division","heading":"Agusta A109 Series Helicopters","content":"### Agusta A109 Series Helicopters\n\n| AD/A109/63 | Battery Bus Circuit Breaker | 9/2009 DM |\n| ---------- | --------------------------- | --------- |\n\n| Applicability: | A109E helicopters as follows:                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|                | - all serial numbers (S/N) up to and including S/N 11077, if equipped with a kit part number (P/N) 109-0812-04-101, -103, -107 or -109, and                                                                                                                                                                                                                                                                                                                                                                   |\n|                | - S/N 11078 to S/N 11758 inclusive, except S/N 11741, 11754 and 11757.                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n| Requirement:   | Modify the fuselage electrical installation P/N 109-0741-49 and the overhead panel electrical installation P/N 109-0741-55, installing the BATT BUS circuit breaker modification kit P/N 109-0824-73-101, in accordance with the instructions of Agusta Bollettino Tecnico 109EP-98 dated 22 June 2009 or later revision approved by the European Aviation Safety Agency (EASA).                                                                                                                              |\n|                | Note: EASA AD 2009-0137 refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| Compliance:    | Within 50 hours time in service after the effective date of this Directive but no later than 31 December 2009, whichever occurs first.                                                                                                                                                                                                                                                                                                                                                                        |\n|                | This Airworthiness Directive becomes effective on 7 July 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| Background:    | Following a report of an electrical failure on one A109E helicopter, the investigations done by the Type Certificate holder have identified the inadequate functioning of the 35 Amperes (Amps) BATT BUS circuit breaker as the reason for the electrical failure.To prevent this unsafe condition, Agusta has developed a BATT BUS circuit breaker modification kit, for the replacement of the 35 Amps circuit breaker with a 50 Amps circuit breaker and the replacement of the wires with oversized ones. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n30 June 2009","sortOrder":0},{"sectionNumber":"AD/A109/63","sectionType":"part","heading":"AD/A109/63","content":"## AD/A109/63","sortOrder":1},{"sectionNumber":"Battery Bus Circuit Breaker","sectionType":"part","heading":"Battery Bus Circuit Breaker","content":"## Battery Bus Circuit Breaker","sortOrder":2},{"sectionNumber":"9/2009 DM","sectionType":"part","heading":"9/2009 DM","content":"## 9/2009 DM","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument sets corrective action for an identified unsafe condition and limits applicability to specified A109E serial numbers and kit configurations. The text contains no indication that the scope was altered from that safety-focused intent."},"complexity_factors":["Technical electrical modification required (breaker swap and wiring upsizing) necessitating qualified maintenance capability.","Applicability tied to precise serial-number ranges and specific kit fitments, requiring record checks.","Reference to manufacturer technical bulletin (Agusta Bollettino Tecnico 109EP-98) and EASA-approved revisions introduces external approvals and version control.","Short compliance window (within 50 flight hours or by a firm calendar date) creates logistical pressure for operators and MROs.","Specific part numbers for installations and kits (P/Ns) require procurement and inventory management.","Regulatory enforcement by CASA with an effective date imposes mandatory compliance and scheduling constraints."],"plain_english_summary":"**What this does:** This directive requires owners/operators of specified Agusta A109E helicopters (particular serial-number ranges and kit fitments) to install a BATT BUS circuit breaker modification kit that replaces a 35 A breaker with a 50 A breaker and oversize wiring, following Agusta technical instructions approved by EASA. \n\n**Who pays and what changes:** Operators must fund and schedule the work within 50 flight hours or by 31 Dec 2009; CASA issued the directive to correct an identified electrical-failure risk."},"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 safety defect in a specific helicopter model. The scope remains tightly focused on the battery bus circuit breaker modification as originally intended."},"complexity_factors":["Single, specific technical requirement with clear part numbers","Limited applicability scope defined by serial number ranges and specific kit part numbers","Straightforward compliance deadline (earlier of two fixed dates)","No nested exceptions or conditional logic beyond the applicability table","Only 4 defined part numbers referenced in the requirement","Single cross-reference to EASA AD 2009-0137 (informational only)"],"plain_english_summary":"This AD requires owners/operators of certain Agusta A109E helicopters (specific serial ranges with a particular electrical kit) to replace a faulty 35A circuit breaker with a 50A unit and fit thicker wiring to eliminate a known in‑flight electrical failure risk.  \n\nCompliance is mandatory: work must start by 7 July 2009 (within 50 flight hours) and be completed no later than 31 December 2009."}},"importantCases":[],"_links":{"self":"/api/acts/ad-a109-63-battery-bus-circuit-breaker","history":"/api/acts/ad-a109-63-battery-bus-circuit-breaker/history","analysis":"/api/acts/ad-a109-63-battery-bus-circuit-breaker/analysis","conflicts":"/api/acts/ad-a109-63-battery-bus-circuit-breaker/conflicts","importantCases":"/api/acts/ad-a109-63-battery-bus-circuit-breaker/important-cases","documents":"/api/acts/ad-a109-63-battery-bus-circuit-breaker/documents"}}