{"id":"F2006B07008","name":"AD/SF340/78 - Landing Gear Electrical Circuit Breaker","slug":"ad-sf340-78-landing-gear-electrical-circuit-breaker","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48647,"registerId":"commonwealth-F2006B07008-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \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.","sortOrder":0},{"sectionNumber":"AD/SF340/78 Landing Gear Electrical Circ","sectionType":"part","heading":"AD/SF340/78 Landing Gear Electrical Circuit Breaker 5/2000","content":"# AD/SF340/78 Landing Gear Electrical Circuit Breaker 5/2000\n\nApplicability: Model SF340A aeroplanes, serial numbers (S/N) 004 through 159 inclusive and Model 340B aeroplanes, S/N 160 through 459 inclusive, except 342, 379, 395, 409,\n\n431 and 455.\n\nRequirement: Install a new electrical circuit breaker and related wiring in accordance with SAAB Aircraft AB Mandatory Service Bulletin SAAB 340-32-120 dated 25 February 2000.\n\nNote: LFV AD 1-155 refers.\n\nCompliance: Within six months from the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 18 May 2000.\n\nBackground: The Swedish Civil Aviation Administration advised that a number of occurrences have been reported of emergency extension of the landing gears being necessary due to a popped circuit breaker which it was not possible to reset. This circuit breaker is also common to the ‘Weight on Wheels’ and ‘Landing Gear Locked Down’ signals to other systems such ‘Nose Wheel Steering’ and ‘Flight Idle Stop’. Not being able to reset the circuit breaker therefore causes failure of the Nose Wheel Steering system which results in reduced capability to steer the aircraft on the ground.\n\nThis Directive requires the addition of a new circuit breaker to supply 28VDC to relays that supply the ‘Weight on Wheels’ and ‘Landing Gear Locked Down’ signals to other systems.\n\n![Signature of Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority](image.003.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 5 April 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 19 April 2000.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This AD imposes a mandatory equipment and wiring modification on the listed aircraft where no such retrofit was previously compulsory, thereby expanding operators' maintenance obligations and altering the aircraft electrical configuration. Key source provisions: Applicability, Requirement (SAAB 340-32-120), Compliance (six months)."},"complexity_factors":["Narrow applicability limited to specific SF340A/340B serial numbers, with several serial-number exceptions (Applicability).","Single, concrete hardware modification required, keeping substantive regulatory change minimal (Requirement).","Technical work is specified by an external SAAB Mandatory Service Bulletin, creating dependence on another document for implementation details (Requirement).","Fixed compliance deadline of six months creates operational scheduling and cost pressure for operators (Compliance).","Modification affects multiple safety-critical systems (Weight on Wheels, Landing Gear Locked Down, Nose Wheel Steering), increasing integration and testing needs (Background)."],"plain_english_summary":"Requires operators of specified SAAB SF340A/340B aeroplanes (listed serial numbers) to install a new 28VDC landing-gear electrical circuit breaker and associated wiring in accordance with SAAB Mandatory Service Bulletin SAAB 340-32-120, within six months. CASA issued the directive to address reports that a popped, unresettable breaker could disable ‘Weight on Wheels’ and ‘Landing Gear Locked Down’ signals and thereby impair Nose Wheel Steering."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains a narrow, targeted scope addressing a specific unsafe condition in a particular aircraft type. The applicability, requirement, and compliance sections are tightly focused on the electrical circuit breaker modification without expansion into unrelated operational or maintenance areas."},"complexity_factors":["Single, specific technical requirement (install one component)","Clear applicability section with explicit serial number ranges and 6 exceptions","Single compliance deadline with no conditional triggers","No defined terms section or interpretive provisions","Background provides straightforward safety rationale","Cross-reference to only one external document (SAAB service bulletin) and one related foreign directive (LFV AD 1-155)"],"plain_english_summary":"This safety order requires owners/operators of certain SAAB 340A (serials 004–159) and 340B (serials 160–459, with six exceptions) to install a new circuit breaker and wiring per SAAB’s service bulletin. It prevents a single breaker failure from disabling landing gear indicators, nose‑wheel steering and engine idle controls, and must be completed by 18 November 2000."},"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-sf340-78-landing-gear-electrical-circuit-breaker","history":"/api/acts/ad-sf340-78-landing-gear-electrical-circuit-breaker/history","analysis":"/api/acts/ad-sf340-78-landing-gear-electrical-circuit-breaker/analysis","conflicts":"/api/acts/ad-sf340-78-landing-gear-electrical-circuit-breaker/conflicts","importantCases":"/api/acts/ad-sf340-78-landing-gear-electrical-circuit-breaker/important-cases","documents":"/api/acts/ad-sf340-78-landing-gear-electrical-circuit-breaker/documents"}}