{"id":"F2006B03657","name":"AD/BEECH 1900/39 - AC Inverters and Synchronisation Wire","slug":"ad-beech-1900-39-ac-inverters-and-synchronisation-wire","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43247,"registerId":"commonwealth-F2006B03657-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\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.\n\n![](image.001.png)\n\nBeechcraft 1900 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/BEECH 1900/39 AC Inverters and Synchr","sectionType":"part","heading":"AD/BEECH 1900/39 AC Inverters and Synchronisation Wire 4/2003","content":"# AD/BEECH 1900/39 AC Inverters and Synchronisation Wire 4/2003\n\nApplicability: Model 1900D aeroplanes in the following groups:\n\nGroup 1 aeroplanes \\- serial numbers (S/N) UE-1 through UE-265, Group 2 aeroplanes - S/N UE-266 through UE-388, and\n\nGroup 3 aeroplanes \\- S/N UE-389 through UE-410.\n\nRequirement: 1. For Group 1, 2 and 3 Aeroplanes \\- Inspect the AC inverter, in accordance with the Accomplishment Instructions section of Raytheon Aircraft Service Bulletin SB 24-3215, Rev. 1, June 2001, to determine if the KGS Electronics AC Inverter part number (P/N) SPC-10(PW), with a serial number in the range of 306 through 803, is installed and is identified as Mod 2DD.\n\nIf, by checking the aeroplane logbook or by visual inspection, it can be positively shown that a Mod 2DD inverter is installed, then Requirement 2 is not applicable.\n\n    2. For Group 1, 2 and 3 Aeroplanes \\- If, during the Requirement 1 inspection, it is found that the Mod 2DD inverter is not installed, accomplish the AC inverter modification in accordance with the Accomplishment Instructions section of SB 24-3215, Rev. 1 and with the Model 1900D Airliner Maintenance Manual (AMM).\n\n    3. For Group 1 Aeroplanes \\- Inspect the AC inverter in accordance with the Accomplishment Instructions section of SB 24-3215, Rev. 1 to determine if United Stated Federal Aviation Administration (FAA) Supplemental Type Certificate STC SA00245WI-D is installed.\n\nIf, by checking the logbook or visual inspection, it can be positively shown that FAA STC SA00245WI-D has never been installed, then Requirement 4 is not applicable.\n\n    4. For Group 1 Aeroplanes \\- If during the Requirement 3 inspection, FAA STC SA00245WI-D is found to be installed, accomplish the AC inverter Synchronisation (sync) wire shield modification in accordance with the Accomplishment Instructions section of SB 24-3215, Rev. 1 and with the Model 1900D AMM.","sortOrder":1},{"sectionNumber":"Beechcraft 1900 Series Aeroplanes","sectionType":"part","heading":"Beechcraft 1900 Series Aeroplanes","content":"## Beechcraft 1900 Series Aeroplanes\n\nAD/BEECH 1900/39 (continued)\n\n    5. For Group 2 Aeroplanes \\- Accomplish the AC inverter sync wire shield modification in accordance with the Accomplishment Instructions section of SB 24-3215, Rev. 1 and with the Model 1900D AMM.\n    6. For Group 1, 2 and 3 Aeroplanes \\- Any KGS Electronics AC inverter P/N SPC-10(PW), with a S/N between 306 through 803 not identified as having Mod 2DD incorporated, may not be installed on any aeroplane as a replacement part.\n\n    7. For Group 1 Aeroplanes \\- FAA STC SA00245WI-D may not be incorporated on any aeroplane unless the Requirement 4 AC inverter modification is accomplished.\n\nNote: FAA AD2003-04-26 Amdt 39-13075 refers.\n\nCompliance: For Requirement 1 \\- Before 21 October 2003.\n\nFor Requirement 2 \\- Before further flight after the Requirement 1 inspection. For Requirement 3 - Before 21 October 2003.\n\nFor Requirement 4 \\- Before further flight after the Requirement 3 inspection. For Requirement 5 - Before 21 October 2003.\n\nFor Requirements 6 and 7 \\- As of the effective date of this Directive. This Airworthiness Directive becomes effective on 17 April 2003.\n\nBackground: The FAA has received nine reports of electrical noise causing the alternating current (AC) inverter to shutdown on certain aeroplanes. These aeroplanes were all equipped with KGS Electronics AC Inverter P/N SPC-10(PW), Mod 2, serial numbers 306 to 803. The shutdown of the inverter resulted in the loss of the electronic flight information system (EFIS), Radio Magnetic Indicator (RMI), and related AC- powered systems. Additionally, some aeroplanes experienced the loss of engine torque indication.","sortOrder":2}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD remains within the original safety task: identify and eliminate an inverter shutdown risk caused by electrical noise on specified KGS SPC-10(PW) units and to ensure related sync‑wire shielding where applicable. The measures (inspection, inverter modification, sync-wire shielding, and prohibitions on fitting unmodified parts or the STC without the modification) are all directed at correcting that single unsafe condition. The AD does not broaden regulatory scope to unrelated systems or add obligations beyond addressing the stated failure mode."},"complexity_factors":["Three distinct applicability groups with specific serial-number ranges (Groups 1–3).","Seven separate Requirements with conditional applicability (Requirements 1–7).","Conditional skips based on positive logbook or visual evidence (e.g. if Mod 2DD is positively shown then Requirement 2 is not applicable).","Cross-references to external documents: Raytheon Service Bulletin SB 24-3215 Rev.1 and the Model 1900D Airliner Maintenance Manual (AMM).","Cross-reference to FAA Supplemental Type Certificate SA00245WI-D and FAA AD2003-04-26 (external certification and regulatory interaction).","Mixed compliance deadlines: some actions 'before further flight', others by a fixed calendar date (21 October 2003), plus immediate prohibitions effective on the AD date.","A prohibition on installing particular serialized parts unless modified (affects supply/parts market).","Requirement referencing both installation status and modification status (P/N, S/N, Mod 2DD) increases factual-check complexity during maintenance."],"plain_english_summary":"**What this directive does (mechanically)**\n\n- This Airworthiness Directive (AD) applies to Beechcraft 1900D aeroplanes with serial numbers in three groups: Group 1 S/N UE-1 to UE-265, Group 2 S/N UE-266 to UE-388, and Group 3 S/N UE-389 to UE-410. (Applicability)\n\n- It requires operators or maintenance organisations to inspect the aircraft AC inverter to find out whether a particular model of KGS Electronics AC inverter (P/N SPC-10(PW), S/N 306–803) and a particular modification status (Mod 2DD) or a particular FAA Supplemental Type Certificate (STC SA00245WI-D) are present. (Requirement 1 and 3)\n\n- If the inverter is present and already has Mod 2DD, no further inverter modification is required. If the inverter is present without Mod 2DD, the AD requires the inverter to be modified in accordance with Raytheon Aircraft Service Bulletin SB 24-3215 Rev.1 and the Model 1900D Airliner Maintenance Manual (AMM). (Requirement 2)\n\n- If STC SA00245WI-D is fitted on a Group 1 aeroplane, the AD requires a separate modification: the AC inverter synchronisation (sync) wire shield modification, again per SB 24-3215 Rev.1 and the AMM. If the STC has never been installed, that sync-wire requirement does not apply. (Requirements 3 and 4)\n\n- For Group 2 aeroplanes the sync wire shield modification is required regardless. (Requirement 5)\n\n- The AD prohibits installing any KGS SPC-10(PW) inverter with S/N 306–803 that is not identified as having Mod 2DD as a replacement part on any aeroplane. (Requirement 6)\n\n- The AD also prohibits incorporating FAA STC SA00245WI-D on any aeroplane unless the sync-wire modification (Requirement 4) has first been accomplished. (Requirement 7)\n\n- Compliance timing: key inspections must be done by 21 October 2003 (Requirements 1 and 3) or before further flight after inspection where specified; some actions are effective immediately as of the AD effective date (17 April 2003). (Compliance)\n\n\n**Why the regulator says this is needed (stated rationale)**\n\n- The FAA reported nine occurrences where electrical noise caused the listed AC inverter models (P/N SPC-10(PW), Mod 2, S/N 306–803) to shut down. Those shutdowns led to the loss of systems powered by that inverter (electronic flight information system, Radio Magnetic Indicator, some engine torque indication). The AD's stated purpose is to prevent inverter shutdown caused by electrical noise and thereby prevent loss of flight instruments. (Background)\n\n\n**Who is affected and who pays**\n\n- Aircraft operators of affected 1900D aeroplanes must organise and pay for the inspections and any required modifications. Maintenance organisations (AMOs) or approved maintenance personnel will perform the work and charge for labour and parts. Airlines or operators also pay for aircraft downtime while inspections/modifications are performed. Parts suppliers may be affected if they hold inventory of the prohibited unmodified inverters (S/N 306–803 without Mod 2DD).\n\n\n**Who decides and how compliance is determined**\n\n- The AD is issued by the CASA delegate and sets mandatory requirements. Compliance is demonstrated by following the Accomplishment Instructions in Raytheon Service Bulletin SB 24-3215 Rev.1 and the Model 1900D AMM, and by logbook entries or visual confirmation where the AD allows skipping certain actions if Mod 2DD or the STC can be positively shown as present or absent. (Requirements 1–4)\n\n\n**Practical consequences, costs and trade-offs**\n\n- Direct compliance costs: time and labour to inspect every affected aeroplane, parts and labour to perform inverter and sync-wire shield modifications where required, and potential costs to source properly modified replacement inverters. These are borne by operators and their maintenance providers. (Requirements 1–6)\n\n- Aircraft downtime and scheduling: inspections required by a fixed date and some modifications 'before further flight' after inspection can cause short-term removals from service and potential route/capacity effects for operators.\n\n- Spare-parts market effect: Requirement 6 forbids installing certain unmodified inverters as replacements. That reduces the pool of acceptable spare inverters and could raise replacement costs or create supply constraints for operators who relied on those serial-numbered units.\n\n- Interaction with STCs and modification chains: Requirement 7 prevents installation of FAA STC SA00245WI-D unless the inverter sync-wire modification is first performed. This constrains retrofit or upgrade choices for operators and STC installers, and makes incorporation of that STC conditional on completing the mandated modification.\n\n- Implementation and administrative friction: the AD relies on service bulletin SB 24-3215 Rev.1 and the aircraft AMM for detailed work steps. Operators must ensure maintenance providers interpret and apply those documents consistently. Where logbook evidence can avoid physical inspection (the AD allows positive logbook evidence to make some requirements not applicable), accurate records reduce workload; poor records may increase unnecessary inspections.\n\n\n**Compliance risk and enforcement**\n\n- The AD sets specific deadlines (some ‘before 21 October 2003’, others ‘before further flight’). Non-compliance risks regulatory enforcement and continued operation with the unsafe condition. The AD is explicit about which modifications are required to make replacement parts or STC incorporation permissible. (Compliance section; Requirements 6–7)\n\n\n**Net effect on private choice and business activity**\n\n- Operators retain the option to continue operating affected aeroplanes, but must perform inspections and, where required, engineering modifications before further flight or by set deadlines. The AD narrows the set of acceptable replacement components and conditions under which an STC may be fitted, reducing short‑term choice around sourcing and retrofitting unless the required modifications are completed. Maintenance providers will see demand for the specified service bulletin work.\n\n\n**Source’s claim vs. costs and trade-offs**\n\n- The AD’s stated safety objective (preventing inverter shutdown from electrical noise) is narrowly matched by the mechanical measures required (inspection, inverter Mod 2DD, and sync-wire shielding). The measures are targeted to the specific hardware (P/N and serial number range) and to aircraft fitted or that can be fitted with the relevant STC. The trade-offs are primarily operational cost, spare-part availability, and scheduling disruption. The AD does not direct broader equipment replacement beyond the affected inverters or require changes to unrelated systems. (Requirements 1–7; Background)\n\n\n**Where to look in the AD for each obligation**\n\n- Which aeroplanes: Applicability section.  \n- Inspect inverter for P/N/S/N and Mod 2DD: Requirement 1.  \n- Modify inverter if no Mod 2DD: Requirement 2.  \n- Inspect for FAA STC and, if present, do sync-wire shield modification: Requirements 3–4.  \n- Sync-wire shield modification mandatory on Group 2: Requirement 5.  \n- Prohibitions on installing unmodified inverters and fitting the STC without the modification: Requirements 6–7.  \n- Deadlines and effective date: Compliance section (effective 17 April 2003; selected compliance deadlines to 21 October 2003 or before further flight).\n\n\n**Bottom line**\n\n- The AD is a focused safety requirement directed at a known failure mode of a specific inverter model and serial-number range. It mandates inspection and, where necessary, modification of the inverter and its sync wire shielding; it also bars using certain unmodified inverters as spares and limits STC incorporation unless the modification is done. Operators pay for and implement the work; the actions are designed to be performed according to an identified service bulletin and the AMM. The main costs are inspection/modification labour, parts, aircraft downtime, and potential constraints on spare-part sourcing."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains focused scope on the specific unsafe condition (AC inverter electrical noise causing shutdown). The grouping of aircraft by serial number and differentiated requirements reflect technical distinctions in aircraft configuration rather than scope creep. The directive addresses the identified safety risk without expanding into unrelated systems."},"complexity_factors":["Multiple aircraft groups (3) with different requirements for each","Nested conditional logic (Requirements 1-2 and 3-4 are dependent pairs)","Cross-references to external technical documents (Raytheon Service Bulletin SB 24-3215, Model 1900D Maintenance Manual)","Specific part numbers and serial number ranges requiring precise identification","Dual regulatory reference (FAA AD 2003-04-26 mentioned in Note)","Multiple compliance deadlines depending on which requirement applies","Technical aviation terminology (STC, Mod 2DD, sync wire shield, EFIS, RMI)"],"plain_english_summary":"CASA has issued a mandatory directive forcing owners/operators of certain Beechcraft 1900D aircraft to inspect and, if necessary, modify or replace KGS SPC-10(PW) AC inverters after reports they shut down from electrical interference. Failures can disable EFIS, navigation indicators and engine torque gauges—critical during takeoff/landing. Inspections must be done by 21 October 2003, required fixes completed before the next flight, and replacement part restrictions apply from 17 April 2003."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-1900-39-ac-inverters-and-synchronisation-wire","history":"/api/acts/ad-beech-1900-39-ac-inverters-and-synchronisation-wire/history","analysis":"/api/acts/ad-beech-1900-39-ac-inverters-and-synchronisation-wire/analysis","conflicts":"/api/acts/ad-beech-1900-39-ac-inverters-and-synchronisation-wire/conflicts","importantCases":"/api/acts/ad-beech-1900-39-ac-inverters-and-synchronisation-wire/important-cases","documents":"/api/acts/ad-beech-1900-39-ac-inverters-and-synchronisation-wire/documents"}}