AD/DA42/2 - Propeller System Check Valve Bracket

The directive rests on a compact set of concepts tied to airworthiness and component integrity.

• Applicability: the AD applies to certain DA42 serial numbers. The "Applicability" box lists "Diamond Aircraft Industries DA 42 model aircraft; DA42 Serial Numbers 42.004 and up including 42.129, and 42.177; and DA 42, Serial Number 42.AC001." That is a positive list rather than an open-ended model designation, so the requirement is limited to the aircraft identified there.

• Required modification and method: the central mandatory action is the installation of an "additional bracket" for the propeller system check valve. The AD prescribes the procedural authority for the physical work: "in accordance with the instructions of Diamond Mandatory Service Bulletin (MSB) 42-024/3 dated 19 September 2006 or later NAA approved revisions." Therefore the MSB supplies the technical drawings, torque settings, parts list and installation steps (the AD does not reproduce those technical details; it delegates them to the MSB).

• Timing: compliance is time‑bounded. The AD requires completion "Within one month or within the next 50 flight hours after the effective date of this directive, whichever occurs first." The directive itself is effective on 10 May 2007.

• Prior work exception: the phrase "Unless already accomplished" operates as an explicit exemption for aircraft that had the modification performed prior to the AD taking effect, provided the modification conforms to the MSB or later NAA‑approved revision referenced.

• Design context: the Background traces the problem to a crack in an aluminium gearbox fitting used to secure propeller-control lines and fittings. The fitting was originally steel and later changed to aluminium by the engine manufacturer; the document identifies a "combination of mass, material and installation torque values" that makes the area critical for cracking. Diamond implemented a production design change, "Design Change MAM 42-184," which incorporated the additional bracket in new aeroplanes.

• Cross‑reference to other regulatory instruments: the AD points users to EASA Airworthiness Directive AD 2006-0277 (6 September 2006), and allows later "NAA approved revisions" of the MSB to be used. Those cross‑references indicate that the technical and regulatory work on this issue was not isolated to this single instrument.

• Scope of applicability includes both aluminium and steel‑fitted machines: the AD emphasises that the retrofit is required "for all airplanes, including the airplanes with steel fittings." That signals that the authority considers the identified risk material regardless of the older fitting material.

These concepts together define the AD as a short, targeted retrofit mandate tied to a single technical corrective action, with a strict short compliance window and reliance on a manufacturer MSB and NAA approvals for method. The AD itself does not set out parts lists or torque values; it delegates technical detail to the MSB.

The AD directly targets a narrow group of aircraft and therefore a defined set of stakeholders.

• Aircraft owners and operators of the named DA42 serial numbers: the "Applicability" box lists the affected aeroplanes explicitly , DA42 Serial Numbers 42.004 and up including 42.129, and 42.177; and DA 42, Serial Number 42.AC001. Owners and operators of those specific aircraft are the primary subjects who must ensure the modification is carried out, unless it has "already [been] accomplished."

• Maintenance organisations and certificated maintenance personnel: the AD requires modification "in accordance with the instructions of Diamond Mandatory Service Bulletin (MSB) 42-024/3 dated 19 September 2006 or later NAA approved revisions." That points maintenance providers to the MSB as the authoritative technical procedure; any work will need to be carried out by personnel authorised to perform that level of modification under their relevant approvals or licences.

• Diamond Aircraft Industries: the manufacturer appears in multiple roles. The MSB is Diamond's document (MSB 42-024/3), Diamond implemented "Design Change MAM 42-184" in production, and the AD is premised on Diamond's identification and resolution of the issue. Diamond will be a source of replacement parts, instructions and certification data for the retrofit.

• Engine manufacturer: the Background records that the fitting was originally steel and "later modified by the engine manufacturer to an aluminium design." The engine manufacturer is implicated as the originator of the component change that led to the cracking issue. The AD does not require any action from the engine manufacturer in this text, but the manufacturer is a stakeholder because its design choice precipitated the problem and any parts or technical data needed may come from it.

• National aviation authorities (NAA) and regulators: the AD permits "later NAA approved revisions" of the MSB; and it notes EASA AD 2006-0277 as reference. Maintenance organisations and operators will need to engage with their NAA where they rely on an NAA‑approved revision of MSB instructions or for any deviation requests.

• Insurers, lessors, and prospective purchasers: while not named, insurers and lessors of affected DA42s will be affected operationally by the requirement to implement the retrofit within prescribed times; prospective purchasers would need to confirm compliance in pre‑purchase checks because the AD sets an airworthiness condition.

• Flight crews and passengers: indirectly affected insofar as the AD addresses an in‑service safety risk that had led to an in‑flight engine shutdown in the Background narrative; completion of the retrofit changes the aircraft's configuration and intended safety profile.

The AD’s phrasing that the requirement applies "for all airplanes, including the airplanes with steel fittings" extends the audience beyond those with the aluminium fitting, increasing the number of aircraft and therefore stakeholders who must act. The document sets no exemptions other than prior accomplishment; it does not, in the text provided, allocate costs, funding or specify who must pay for parts and labour , those follow normal commercial arrangements between owners/operators and maintenance providers.

The AD creates a discrete set of duties, and a narrow procedural right (to rely on prior accomplishment).

Duties

• Modify the aircraft by installing the additional bracket: the central duty is to carry out the retrofit. The AD language is mandatory: "Unless already accomplished, modify the aircraft by installing the additional bracket..." That places an affirmative obligation on an operator/owner of an affected aeroplane that has not already been modified.

• Follow the MSB or later NAA‑approved revisions: the method of compliance is confined to Diamond Mandatory Service Bulletin 42-024/3 dated 19 September 2006 or "later NAA approved revisions." That duty constrains which technical instructions can be used; it requires the use of the manufacturer’s procedure as approved by a National Aviation Authority. The AD does not itself include the technical procedure, it mandates adherence to it.

• Comply within the stated timeframe: the AD sets a strict deadline , "Within one month or within the next 50 flight hours after the effective date of this directive, whichever occurs first." The AD is effective from 10 May 2007, so duties must be met within that window measured from the effective date.

• Ensure applicability is correctly determined: operators must determine whether their aeroplane is within the listed serial numbers. The AD applies to DA42 Serial Numbers 42.004 and up including 42.129, 42.177, and DA42 Serial Number 42.AC001 , owners must check serial numbers against maintenance and registration records.

Rights and limited defences

• "Unless already accomplished": the AD expressly recognises that aircraft on which the modification has already been carried out are not required to repeat it. That creates a right to recognise prior compliance as satisfying the AD.

• Use of later NAA‑approved MSB revisions: operators/maintenance providers have the right to comply using later revisions of MSB 42-024/3 provided those revisions are NAA approved. This offers a limited procedural flexibility to use updated or clarified technical instructions if authorised by the relevant authority.

What the AD does not specify (and therefore creates duties by implication for operators to address administratively)

• The AD does not specify documentation requirements such as logbook entries to record compliance, but standard practice would be to record modifications. The AD text itself does not set out documentary particulars.

• The AD does not specify who pays for parts and labour or the method of proof of compliance beyond following the MSB; those commercial duties remain with the owner/operator and their maintenance providers under ordinary arrangements.

• The AD does not state any waiver mechanism or present any routine process for deviations. The only flexibility stated is the allowance of "later NAA approved revisions" of the MSB as the basis for compliance work.

Operators should therefore treat the AD as a binding requirement to retrofit according to the MSB within the short prescribed timeframe unless they can demonstrate the modification has already been accomplished in accordance with the cited MSB or an NAA‑approved revision.

The AD text as supplied does not contain express penalty provisions, sanctions or detailed enforcement mechanisms. The instrument sets a mandatory technical requirement, an effective date and a compliance deadline, and is signed by the CASA Delegate, but it does not in the supplied text articulate the consequences of non‑compliance such as fines, grounding orders, or administrative enforcement steps.

From what the document contains:

• The directive becomes effective on 10 May 2007, and compliance is required "Within one month or within the next 50 flight hours after the effective date of this directive, whichever occurs first." The AD is presented as a prescriptive instrument , it is not framed as advisory.

• The signatory is a CASA Delegate (Charles Lenarcic), dated 27 March 2007, which identifies the issuing authority in an administrative capacity. The AD references other airworthiness instruments (EASA AD 2006-0277) and requires adherence to a Diamond MSB or later NAA‑approved revisions. Those cross‑references indicate this instrument forms part of a regulatory and technical framework.

What the AD does not say and the practical implications

• The AD does not, in the supplied text, set out criminal, civil or administrative penalties for non‑compliance. It also does not reproduce the general enforcement provisions that might exist elsewhere in aviation law or CASA regulatory instruments. The absence of explicit penalties in this document means any enforcement or penalty regime would have to be located in other statutory or regulatory materials; those are not contained in or quoted by the AD as provided.

• The AD similarly does not set out the mechanism of compliance verification (for example, inspection by regulator, requirement to submit compliance reports, or logbook endorsement format). Operators are left to infer that compliance will be evidenced by following the MSB and retaining records, but the AD text itself does not describe the documentary proof needed.

Given the AD’s mandatory wording and the fact it is issued by the Delegate of the Civil Aviation Safety Authority, operators should treat it as an enforceable airworthiness requirement and align their compliance and record‑keeping practices accordingly. For any question about legal consequences or enforcement steps, operators would need to consult CASA’s broader regulatory framework or seek specific guidance from CASA or their NAA; that material is not included in the AD itself.

The AD makes limited explicit cross‑references to other regulatory instruments, but the supplied text does not attempt to map out its relation to specific statutes or regulations.

Explicit interactions in the text

• Reference to EASA AD: the AD contains a "Note" stating "EASA Airworthiness Directive AD 2006-0277 dated 6 September 2006 refers." That indicates the technical or regulatory origin of the issue was also addressed by the European Aviation Safety Agency and that the CASA AD aligns with or recognises EASA’s action on the component.

• Reliance on NAA approvals: the AD permits adherence "in accordance with the instructions of Diamond Mandatory Service Bulletin (MSB) 42-024/3 dated 19 September 2006 or later NAA approved revisions." The phrase "NAA approved revisions" embeds the interaction: national aviation authorities have the competency to approve subsequent revisions of the MSB that would be acceptable means of compliance.

Unstated interactions that are logically implicated though not present in the text

• The AD does not cite or reproduce the enabling legislation or CASA regulations authorising the AD. The document is presented as an airworthiness directive from CASA's delegate; to understand the formal legal basis for the AD one would need to consult the Civil Aviation Act, Civil Aviation Safety Regulations, or other CASA instruments. Those enabling legal texts are not quoted in the AD as supplied.

• The AD delegates technical execution to a manufacturer MSB and to NAA approval processes. That situates it within the usual regulatory architecture where airworthiness directives mandate compliance and service bulletins provide the technical method. Interactions with broader maintenance and continuing airworthiness requirements are implied but not spelled out in the AD text.

• The AD’s effective date and short compliance window will interact with operators’ obligations under other operational rules (for example, record keeping, airworthiness certification, and continued flight release) but the AD itself does not specify those interfaces.

Practical points for operators and maintainers

• Where operators rely on a later MSB revision, they must ensure it is NAA approved, because the AD only permits "later NAA approved revisions." That requires interaction with the relevant NAA for approval confirmation.

• If the operator needs to demonstrate compliance for registration, lease, sale or insurance purposes, evidence will need to be produced under those other regulatory or contractual frameworks; the AD itself does not standardise what documentary proof is required.

• For aircraft registered outside CASA’s jurisdiction but in the serial range listed, the AD’s note that EASA issued AD 2006-0277 suggests related obligations may exist elsewhere; operators should check their local NAA and the EASA AD for harmonised obligations.

In summary, the AD explicitly interacts with the EASA AD and with NAA approval pathways for MSB revisions, but it does not, within its text, cite enabling statutes, specify enforcement mechanisms under other laws, or prescribe document formats for proof of compliance. Those interactions must be handled through the broader regulatory framework administered by CASA and by the relevant NAA.

The AD as presented contains limited internal amendment history. The document does, however, incorporate references to related technical documents and a production design change that together constitute the historical development that led to the AD.

Items in the AD that record historical steps

• Service Bulletin dating: the AD mandates compliance "in accordance with the instructions of Diamond Mandatory Service Bulletin (MSB) 42-024/3 dated 19 September 2006 or later NAA approved revisions." That identifies MSB 42-024/3 (19 September 2006) as the controlling technical instruction at the time the AD was issued, and allows for later NAA‑approved revisions to be used. The inclusion of the MSB date is a snapshot in the MSB revision history: the AD recognises the MSB as the basis for remedial action and anticipates that the MSB could be revised subsequently, subject to NAA approval.

• EASA AD reference: the "Note" refers to "EASA Airworthiness Directive AD 2006-0277 dated 6 September 2006." That EASA AD preceded the Diamond MSB date and the CASA AD effective date, indicating a sequence where EASA issued an AD (6 September 2006), Diamond issued MSB 42-024/3 (19 September 2006), and CASA issued this AD effective 10 May 2007. The AD itself does not chronicle subsequent amendments made after its issue.

• Production design change: the Background identifies that "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." That documents that the remedy was already implemented for production aircraft via a design change, and the AD extends the modification requirement to earlier production and in‑service airplanes.

What the AD does not contain

• The AD text does not show any amendments to the AD itself. There is no section titled "Amendment" or "Revocation" or subsequent effective dates beyond the stated effective date of 10 May 2007 in the supplied material.

• The AD does not list a revision history for itself, or indicate that it has been superseded or updated; nor does it reproduce subsequent NAA approvals or later MSB revisions beyond the permissive language that allows them.

Implication for records and compliance

• Operators and maintainers who rely on later revisions of MSB 42-024/3 must ensure those revisions are NAA approved, and should document which MSB revision they used to satisfy the AD. Because the AD refers to a particular MSB revision as well as permitting later NAA‑approved revisions, maintaining a contemporaneous trail of which MSB version and NAA approval were relied on will be essential to evidence compliance.

• If one needs to know whether CASA has since amended or superseded this AD, or whether the MSB has been revised, that information would have to be obtained from CASA's AD database, Diamond’s service bulletin archive, or the relevant NAA , the supplied AD text does not contain later amendment entries.

In short, the AD captures a brief trace of the prior technical steps (EASA AD, Diamond MSB, Design Change MAM 42-184) that gave rise to a retrofit requirement; it does not, in the supplied text, contain or record any amendments made to the AD after its issue.

The supplied text contains no litigation history. It does not mention any appeals, challenges, court cases, tribunal actions, or other dispute resolution proceedings relating to this AD, nor does it cite any judicial or administrative decisions. The document is a stand‑alone airworthiness directive that records a safety issue, prescribes a corrective modification and identifies the relevant MSB and EASA AD references; it makes no reference to any litigation.

What the absence means for practitioners

• Because the AD includes no litigation history, there is no source‑grounded material in this document about any legal disputes, whether concerning the technical facts, the scope of applicability, the adequacy of the MSB, or the authority of the issuer. If a practitioner needs to know whether the AD has been subject to legal challenge, or whether there are precedential decisions interpreting an equivalent instrument, they would need to consult external databases, CASA records or legal reporting services; those sources are not part of the AD text provided.

• The absence of litigation references in the AD does not indicate whether disputes took place outside the document. It simply means the AD itself neither records nor addresses any legal proceedings.

For legal or compliance work where litigation risk or precedents are material, one must search judicial, administrative and regulatory records beyond the AD as supplied.

The AD contains several technical and procedural details that can create practical pitfalls if not handled deliberately.

• Narrow applicability wording: the list of affected serial numbers is specific: "DA42 Serial Numbers 42.004 and up including 42.129, and 42.177; and DA 42, Serial Number 42.AC001." That phrasing can be misread. Operators should confirm exact serial numbers against the aircraft’s official identification to determine whether the AD applies. Misidentifying the serial number could lead to unnecessary work or missed compliance.

• "Unless already accomplished" requires documentary proof: the AD excludes aeroplanes on which the modification has already been done, but the AD does not set out what documentation suffices to demonstrate prior accomplishment. Operators must ensure their maintenance records unambiguously show the bracket was installed in accordance with MSB 42-024/3 (or a later NAA‑approved revision) prior to the AD's effective date. Without clear records, an operator may be treated as non‑compliant even if the physical work was done.

• Short compliance window: compliance is required "Within one month or within the next 50 flight hours after the effective date ... whichever occurs first." The combination of a calendar and flight‑hour limit can catch operators who fly frequently. Planning maintenance (sourcing parts, booking a maintenance slot, arranging ferry flights if needed) must take the shorter of the two limits into account; otherwise an aircraft could exceed the 50‑flight‑hour threshold before the modification is installed.

• Use only NAA‑approved MSB revisions: the AD allows "later NAA approved revisions" of the MSB, but those revisions must be NAA‑approved. Relying on an informal or manufacturer's draft revision that lacks NAA approval would not meet the AD’s terms. Operators must confirm that any MSB revision relied upon is formally approved by the appropriate authority.

• Applies to aircraft with steel fittings as well: the AD explicitly states it "requires installation of this bracket for all airplanes, including the airplanes with steel fittings." An operator with a DA42 that retains the original steel fitting might assume the risk is only for aluminium‑fitted machines; the AD forecloses that assumption and imposes the retrofit obligation regardless of the existing fitting material.

• No technical detail reproduced: the AD does not include the MSB’s parts list, torque values or installation steps. Practitioners must obtain MSB 42-024/3 (or a later NAA‑approved revision) to know the exact technical requirements. Failure to use the proper MSB version or approved revision may lead to non‑compliance.

• No penalties specified in the text: while the AD is prescriptive, it does not enumerate enforcement or penalty mechanisms. That can create ambiguity about consequences for late compliance or non‑compliance; operators should not infer leniency from that absence and should proactively comply within the stated period.

• Interaction with record‑keeping/airworthiness proofs: the AD does not state the form of compliance evidence (logbook entry, certificate, form number). Operators should ensure that any compliance entry clearly references the AD, the MSB revision used, the date of completion, and the signature of the authorised maintenance person or organisation to avoid disputes later.

• Cross‑jurisdictional considerations: the AD references EASA AD 2006‑0277 and accepts NAA‑approved MSB revisions. For aircraft registered outside Australia, operators must consider their own NAA requirements and whether this CASA AD has direct applicability or merely informative value.

Because the AD is short and narrowly focused, these procedural details,serial number accuracy, documentary proof of prior accomplishment, strict timing, and correct MSB/approval reliance,are the primary operational risks. Practitioners should treat them as compliance chokepoints and plan accordingly.

The AD sets out a straightforward compliance pathway, but practical execution requires attention to method, timing and records. The AD’s operative instruction is: "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." Follow these steps to align with the AD as written.

1. Determine applicability

• Confirm the aircraft’s serial number against the AD’s list: DA42 Serial Numbers 42.004 and up including 42.129, and 42.177; and DA42 Serial Number 42.AC001. If the serial number is within that list, proceed. Keep documentary evidence of the serial‑number check (registration documents, manufacturer data plate, logbooks).

2. Check whether the modification is "already accomplished"

• Inspect maintenance records and physical configuration to see if the additional bracket has already been installed prior to the AD’s effective date (10 May 2007). If prior work exists, ensure the record specifies that the installation followed MSB 42-024/3 dated 19 September 2006 or a later NAA‑approved MSB revision. If records are ambiguous, consider re‑performing or re‑documenting the installation per MSB to generate clear evidence.

3. Obtain the MSB and confirm revision/approval status

• Obtain Diamond Mandatory Service Bulletin 42-024/3 (dated 19 September 2006). If a later revision of that MSB is to be used, verify that the revision is NAA approved before proceeding, because the AD only allows "later NAA approved revisions." Maintain copies of the MSB and any NAA approval documents used.

4. Schedule and perform the work within the compliance window

• The AD requires the installation "Within one month or within the next 50 flight hours after the effective date of this directive, whichever occurs first." The effective date is 10 May 2007. Schedule the retrofit to ensure the work is completed before exceeding 50 flight hours or one month from the effective date, whichever is earlier. Coordinate parts procurement, booking with an appropriately authorised maintenance organisation, and any ferry flight requirements.

5. Ensure authorised personnel and correct technique

• The AD binds the operator to comply "in accordance with the instructions" of the MSB. Use maintenance personnel who are authorised to perform structural/engine‑installation work and who will follow the MSB’s torque values, configuration and inspection guidance. The AD does not reproduce technical values; they must be taken from the MSB.

6. Document compliance clearly

• Even though the AD does not specify a documentary format, record the installation in the aircraft maintenance records/logbook with:
  • Reference to CASA AD AD/DA42/2 (Propeller System Check Valve Bracket) and the effective date (10 May 2007).
  • The MSB revision used and any NAA approval reference for that revision.
  • Date of completion and the total flight hours at completion.
  • Signature, licence number and organisation of the certifying maintenance person.
• Retain the MSB and proof of NAA approval as part of the maintenance file.

7. Verify post‑installation condition and returns to service

• Perform any functional checks or inspections required by the MSB to verify installation integrity. Ensure required tests (if any) are completed and recorded before returning the aircraft to service.

8. Address any unexpected findings

• If during installation a more extensive defect is found (for example, cracking that requires additional repair), follow MSB instructions for disposition and consult the manufacturer or NAA as necessary. The AD itself does not provide alternative repair pathways beyond the MSB.

9. Notify lessees/insurers/registries as required

• Where contractual or regulatory relationships require notification of AD compliance (for example, lessor consent or insurer notification), provide them with the compliance documentation described above.

10. For operators outside CASA jurisdiction

• Check whether the equivalent EASA AD (AD 2006-0277) or local NAA mandates similar or identical action, and whether NAA approvals are required locally for MSB revisions. The AD notes the EASA AD reference, so alignment with that AD is relevant for operators registered in EASA states.

Following the AD literally requires reliance on the MSB for technical details and strict observance of the compliance window. The critical practical tasks are confirming applicability, verifying prior accomplishment, securing the correct MSB revision and any NAA approvals, scheduling and performing the installation promptly, and creating clear documentary evidence of compliance.