{"id":"F2007L04359","name":"AD/DA42/3 Amdt 2 - Engine Control Unit Back-Up Batteries","slug":"ad-da42-3-amdt-2-engine-control-unit-back-up-batteries","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":70653,"registerId":"commonwealth-F2007L04359-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Diamond DA42 Series Aeroplanes","sectionType":"division","heading":"Diamond DA42 Series Aeroplanes","content":"### Diamond DA42 Series Aeroplanes\n\n| AD/DA42/3 Amdt 2 | Engine Control Unit Back-Up Batteries | 1/2008 TX |\n| ---------------- | ------------------------------------- | --------- |\n\n| Applicability: | DA 42 aeroplanes, serial numbers (S/N) 42.004, 42.006, 42.009 through 42.156, 42.158 through 42.176, 42.178 through 42.190, 42.192 through 42.233, 42.235 through 42.246, 42.248 through 42.254, 42.256 through 42.261, 42.263 through 42.269 and Canadian production line aeroplanes S/N 42.AC001 through 42.AC109. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement: | 1. Modify the engine electrical system by installing additional engine control unit (ECU) backup batteries in accordance with Diamond Aircraft Industries GmbH (DAI) Mandatory Service Bulletin (MSB) 42-042 dated 22 June 2007 and DAI Work Instruction WI-MSB-42-042 dated 20 June 2007 or later revisions of these documents approved by the European Aviation Safety Agency (EASA). |\n| | 2. Amend the DA 42 Aircraft Maintenance Manual by inserting DAIAMM-TR-MÄM-42-240 Temporary Revision (TR) dated 17 June 2007 or later EASA approved AMM revision, update the operator’s maintenance programme and maintain the aircraft accordingly. |\n| | 3. Amend the DA 42 Aircraft Flight Manual (AFM) by inserting a copy of AFM TR-MÄM-42-240 dated 17 June 2007 or later EASA approved AFM revision, into the AFM, as instructed in that document. |\n| | AMM and AFM TRs incorporated in accordance with this Directive may be removed when the information contained in the TR is incorporated in the manual during the normal revision process. |\n| | Modification of the engine electrical system of the DA 42 and accomplishment of related actions in accordance with the instructions contained in DAI Optional Service Bulletin (OSB) 42-050/1 dated 15 October 2007 or later EASA approved revision, including associated documents referenced therein, has been approved by the EASA as an alternative method of compliance for the requirements of AD 2007-0183 R2. Accomplishment of DAI OSB 42-050/1 is also acceptable as an alternate method of compliance for this Directive. |\n| | Note: EASA AD 2007-0183 R2 (corrected 7 November 2007) refers. |\n\n| Compliance: | For Requirements 1 through 3 - Within the next 200 hours time in service after the effective date of the original issue of this Directive, but not later than 30 November 2007, whichever occurs first. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| | This Amendment becomes effective on 16 November 2007. |\n| Background: | Recently, a double in-flight engine shut down incident occurred on a DA42 aircraft equipped with TAE125-01 engines. The Bundesstelle für Flugunfalluntersuchung (German Federal Bureau of Aircraft Accident Investigation) found the root cause to be a violation of the AFM procedures (taking-off with an insufficiently charged main aircraft battery) and momentary low voltage in the electrical system of the aircraft when retracting the main landing gear. This has been the subject of Diamond Service Information (SI) 42-040 dated 9 March 2007. |\n| | The TAE125-01 and TAE125-02-99 engines, approved for installation on the DA42, are full authority digital engine control (FADEC) controlled and are not totally independent from the aircraft electrical power supply. A significant drop of the voltage caused a simultaneously reset of the FADEC on both engines with subsequent feathering of the propeller blades. Thielert Aircraft Engines (TAE) Installation Manuals IM-02-01 Issue 4 and IM-02-02 Issue 1 have been revised to address this issue. |\n| | The original issue of this Directive mandated the installation of additional ECU backup batteries to supply electrical power to the ECU, preventing high transient power drains from causing a short term voltage drop when their insufficient charge in the main battery. The Directive also required the incorporation of AFM and AMM TRs. |\n| | Amendment 1 continued the requirements of the original issue of this Directive but allows compliance in accordance with later EASA approved revisions of the requirement documents. |\n| | This Amendment continues the requirements of Amendment 1 but introduces an optional alternate method of compliance as approved by the EASA and extends compliance by an additional 100 hours time in service until 30 November 2007. |\n| | The original issue of this Directive became effective on 27 July 2007. |\n| | This Amendment becomes effective on 7 September 2007. |\n\n![](image.001.png) \nDavid Punshon \nDelegate of the Civil Aviation Safety Authority\n\n13 November 2007","sortOrder":0},{"sectionNumber":"AD/DA42/3 Amdt 2","sectionType":"part","heading":"AD/DA42/3 Amdt 2","content":"## AD/DA42/3 Amdt 2","sortOrder":1},{"sectionNumber":"Engine Control Unit Back-Up Batteries","sectionType":"part","heading":"Engine Control Unit Back-Up Batteries","content":"## Engine Control Unit Back-Up Batteries","sortOrder":2},{"sectionNumber":"1/2008 TX","sectionType":"part","heading":"1/2008 TX","content":"## 1/2008 TX","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"Amendment 2 preserves the original requirement to install ECU backup batteries and to insert AMM/AFM temporary revisions but introduces an EASA‑approved optional alternate method of compliance (DAI OSB 42‑050/1) and extends the compliance window by an additional 100 hours until 30 November 2007; it also permits use of later EASA‑approved revisions of the mandated documents."},"complexity_factors":["Applicability limited to a long, specific list of DA42 serial numbers (targets subset of fleet).","Technical cause involves FADEC dependence on aircraft electrical supply and transient low‑voltage events (requires electrical modification to mitigate).","Multiple required actions: hardware installation (ECU backup batteries), AMM and AFM temporary revisions, and maintenance‑programme updates.","Compliance timing constraint: originally within 200 flight hours or by 30 Nov 2007; Amendment 2 extends the deadline by 100 hours (adds scheduling complexity).","Alternative method of compliance allowed (DAI OSB 42‑050/1) but only if EASA‑approved, creating conditional compliance paths and documentation tracking.","Document control: specified DAI MSB and Work Instruction or later EASA‑approved revisions must be used, increasing regulatory coordination and version management.","Operational impact: aircraft downtime and labour/parts cost for retrofit, plus ongoing recordkeeping and manual-change maintenance burden."],"plain_english_summary":"**Directive:** This requires installing additional engine-control-unit (ECU) backup batteries and inserting temporary AMM/AFM revisions on specified Diamond DA42 serial numbers to prevent simultaneous FADEC resets and double in‑flight engine shutdowns. Affected owners/operators must arrange and fund the modification and manual updates within the stated compliance window; an EASA‑approved alternative compliance method is permitted."},"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":3,"scope_assessment":{"changed":false,"description":"This Amendment 2 stays tightly focused on the original safety issue (ECU backup batteries following the double engine failure incident). It extends compliance time and adds an alternative method, but does not expand into unrelated systems or aircraft types."},"complexity_factors":["Short, single-purpose directive with only 3 core requirements","Heavy reliance on external technical documents (MSB, OSB, Work Instructions, Temporary Revisions) rather than spelling out procedures in the text itself","Multiple serial number ranges listed in applicability (though this is standard for aircraft ADs)","One alternative method of compliance (AMOC) referenced, adding a conditional path","Cross-references to EASA (European) approvals and German accident investigation reports","No defined terms section — assumes aviation technical knowledge"],"plain_english_summary":"This AD requires owners/operators of specified Diamond DA42 aircraft to fit additional backup batteries for the Engine Control Units and to update maintenance and flight manuals accordingly. It targets certain European- and Canadian-built DA42s by serial number.\n\nIt responds to a safety-critical incident where weak main battery power allowed ECUs to reset and both engines to shut down; the backups keep ECUs powered. Compliance was required within 200 flight hours or by 30 November 2007."}},"importantCases":[],"_links":{"self":"/api/acts/ad-da42-3-amdt-2-engine-control-unit-back-up-batteries","history":"/api/acts/ad-da42-3-amdt-2-engine-control-unit-back-up-batteries/history","analysis":"/api/acts/ad-da42-3-amdt-2-engine-control-unit-back-up-batteries/analysis","conflicts":"/api/acts/ad-da42-3-amdt-2-engine-control-unit-back-up-batteries/conflicts","importantCases":"/api/acts/ad-da42-3-amdt-2-engine-control-unit-back-up-batteries/important-cases","documents":"/api/acts/ad-da42-3-amdt-2-engine-control-unit-back-up-batteries/documents"}}