{"id":"F2007L01057","name":"AD/DA42/2 - Propeller System Check Valve Bracket","slug":"ad-da42-2-propeller-system-check-valve-bracket","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":65010,"registerId":"commonwealth-F2007L01057-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/DA42/2 | Propeller System Check Valve Bracket | 5/2007 |\n| --------- | ------------------------------------ | ------ |\n\n| Applicability: | Diamond Aircraft Industries DA 42 model aircraft;DA42 Serial Numbers 42.004 and up including 42.129, and 42.177; andDA 42, Serial Number 42.AC001.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Unless already accomplished, modify the aircraft by installing the additional bracket in accordance with the instructions of Diamond Mandatory Service Bulletin (MSB) 42-024/3 dated 19 September 2006 or later NAA approved revisions.Note: EASA Airworthiness Directive AD 2006-0277 dated 6 September 2006 refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| Compliance:    | Within one month or within the next 50 flight hours after the effective date of this directive, whichever occurs first.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n|                | This Airworthiness Directive becomes effective on 10 May 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| Background:    | Shortly after an engine change, the aluminium fitting attached to the engine gearbox holding lines and fittings of the propeller control system was found to be cracked. This led to a pressure loss in the propeller control system following a control system malfunction and led to an in-flight engine shutdown.The broken fitting is part of the engine installation and was initially a steel part. It was later modified by the engine manufacturer to an aluminium design. Investigation determined that the area is critical for cracks due to combination of mass, material and installation torque values.With Design Change MAM 42-184, Diamond Aircraft Industries incorporated an additional bracket into the production airplanes to improve the installations and prevent vibration cracks. |\n\n|     | This Airworthiness Directive requires installation of this bracket for all airplanes, including the airplanes with steel fittings. |\n| --- | ---------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n27 March 2007","sortOrder":0},{"sectionNumber":"AD/DA42/2","sectionType":"part","heading":"AD/DA42/2","content":"## AD/DA42/2","sortOrder":1},{"sectionNumber":"Propeller System Check Valve Bracket","sectionType":"part","heading":"Propeller System Check Valve Bracket","content":"## Propeller System Check Valve Bracket","sortOrder":2},{"sectionNumber":"5/2007","sectionType":"part","heading":"5/2007","content":"## 5/2007","sortOrder":3}],"analysis":{"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"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"The directive extends the production design change (Design Change MAM 42-184, which added the bracket to new production aeroplanes) into a mandatory retrofit for in-service aeroplanes, including those that retained the original steel fittings. In other words, the measure moves from a production fix to a fleet-wide mandatory modification, increasing the scope of who must act (all affected in-service aircraft) and who bears retrofit costs compared with the original production-only change."},"complexity_factors":["Single mandated action: install additional bracket per MSB 42-024/3","Short, single compliance condition (whichever occurs first: 1 month or 50 flight hours)","Limited applicability list (specific serial numbers plus one additional serial)","Cross-reference to a single external technical document (Diamond MSB 42-024/3) and to EASA AD 2006-0277","No layered exceptions or multi-step criteria; straightforward retrofit requirement","Includes explanatory background but no complex regulatory or procedural routing"],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Requires installation of an additional bracket on the propeller control system installation of certain Diamond DA42 aeroplanes.  The work must be carried out \"in accordance with the instructions of Diamond Mandatory Service Bulletin (MSB) 42-024/3 dated 19 September 2006 or later NAA (National Aviation Authority) approved revisions.\" (Requirement)\n- Compliance must be completed \"within one month or within the next 50 flight hours after the effective date of this directive, whichever occurs first.\" (Compliance)\n\n**Which aeroplanes it affects**\n\n- Applies to Diamond Aircraft Industries DA42 model aircraft with serial numbers 42.004 and up including 42.129, and 42.177; and DA42 serial number 42.AC001. (Applicability)\n\n**Why it was introduced (official rationale)**\n\n- After an engine change an aluminium fitting attached to the engine gearbox (which holds lines and fittings of the propeller control system) cracked. That cracking led to a loss of pressure in the propeller control system, a subsequent control-system malfunction and an in-flight engine shutdown. The fitting had originally been a steel part and later changed to aluminium; the investigation identified the location as prone to cracking because of the combination of mass, material and installation torque values. Diamond introduced a design change (MAM 42-184) that adds a bracket in production aeroplanes to reduce vibration-induced cracking. The AD mandates adding the same bracket to affected in-service aeroplanes. (Background)\n\n**Who pays and who decides**\n\n- Aircraft owners/operators pay for the parts and labour to install the bracket and for aircraft downtime while the modification is performed. (Requirement & Compliance)\n- The Civil Aviation Safety Authority (via the Delegate who issued the directive) requires compliance; operators decide when and through which maintenance provider to carry out the work, subject to the MSB instructions and any NAA-approved revisions. (Requirement)\n\n**Practical effects on behaviour and operations**\n\n- Operators must schedule the modification within the short compliance window (1 month or 50 flight hours), which may require urgent maintenance slots and may cause temporary grounding or reduced availability while the work is done.\n- Maintenance must follow the manufacturer’s Mandatory Service Bulletin (or later approved revision); independent maintenance organisations can carry out the work provided they follow that approved procedure.\n\n**Costs, incentives and trade-offs**\n\n- Direct costs: parts, labour and aircraft downtime payable by owners/operators. These are concentrated on the specific DA42 serial-number subset identified.\n- Benefits: reduced risk of propeller-control system pressure loss from cracking at that fitting; the benefit accrues primarily to those operators and their passengers/clients.\n- Opportunity costs: time and maintenance capacity spent on this retrofit instead of other checks or operations.\n- Implementation risk and constraints: availability of the bracket parts and qualified maintenance capacity may affect how quickly the fleet can comply; the AD ties compliance to a manufacturer MSB (or NAA-approved revision), so the exact technical procedure and parts are prescribed rather than open to operator-devised fixes.\n\n**Effects on markets, competition and independent businesses**\n\n- The AD imposes a uniform technical requirement across specified DA42s; it does not restrict which licensed maintenance provider may perform the work, so independent maintenance businesses can compete to supply the service subject to meeting the MSB procedures.\n- There is a small compliance cost that may slightly affect operating costs for affected aircraft but is unlikely to materially affect competition in broader markets.\n\n**Implementation and enforcement note**\n\n- The directive becomes effective on the stated effective date; failure to comply within the set timeframe can expose operators to regulatory enforcement and will leave aircraft non-compliant with the airworthiness directive. The AD references EASA AD 2006-0277 and requires following Diamond MSB 42-024/3 (or later NAA-approved revisions), so compliance is demonstrated by performing the modification per those documents.\n\n**Bottom line**\n\n- The AD mandates a retrofit bracket installation on a defined set of DA42 aeroplanes within a short timeframe to address a cracking risk in the propeller control system installation. Owners/operators bear the costs and must arrange approved maintenance following the manufacturer’s MSB or approved revision to meet the directive.\n"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — a targeted safety fix for a specific mechanical defect in a single aircraft type. The requirement applies to all affected aircraft without expansion into broader operational or maintenance regimes."},"complexity_factors":["Single, specific mechanical modification required","Only 3 defined applicability criteria (serial number ranges)","One compliance pathway with simple alternative timing (1 month OR 50 hours)","No nested exceptions or conditional logic","References only one external technical document (Diamond MSB 42-024/3)","Short document (~250 words of substantive content)"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of specified Diamond DA42 aircraft (s/n 42.004 and up, including 42.129, 42.177, and 42.AC001) install an additional metal bracket on the propeller control per Diamond MSB 42‑024/3. The bracket, required within 1 month or 50 flight hours from 10 May 2007, prevents vibration‑induced cracking that can cause propeller control loss — and applies even to aircraft still fitted with the original steel part."}},"importantCases":[],"_links":{"self":"/api/acts/ad-da42-2-propeller-system-check-valve-bracket","history":"/api/acts/ad-da42-2-propeller-system-check-valve-bracket/history","analysis":"/api/acts/ad-da42-2-propeller-system-check-valve-bracket/analysis","conflicts":"/api/acts/ad-da42-2-propeller-system-check-valve-bracket/conflicts","importantCases":"/api/acts/ad-da42-2-propeller-system-check-valve-bracket/important-cases","documents":"/api/acts/ad-da42-2-propeller-system-check-valve-bracket/documents"}}