AD/THIELERT/6 - Engine Oil System - Catchtank (Sump) Filter Adapter

The primary persons and entities directly affected are owners and operators of Thielert TAE125-01 engines bearing serial numbers up to and including 02-01-1018, wherever those engines are operated under Australian jurisdiction. That covers aircraft in which these engines are installed; the AD lists aircraft types where the engines are known to be fitted, namely Cessna 172 and Reims-built F172 series (EASA STC Nr. EASA.A.S.01527), Piper PA-28 series (EASA STC Nr. EASA.A.S.01632), APEX (Robin) DR 400 series (EASA STC Nr. EASA.A.S.01380), and Diamond DA40 and DA42 series aircraft. The “Applicability” paragraph limits the class of engines, so operators of aircraft with later serial-numbered engines (beyond s/n 02-01-1018) are not covered by this AD as drafted.

Maintenance organisations and engineers who will carry out the modification are affected operationally, because the AD prescribes the method of compliance: modification in accordance with Thielert TM/SB TAE 125-0016 (initial issue 19 September 2006 or Revision 1 dated 15 June 2007). That makes the SB the operative technical authority for installation, parts, and procedure. Thielert, the engine type certificate holder and developer of the filter adaptor, is implicated as the supplier of the technical material and the hardware adaptation referenced in the AD; the AD explicitly records that Thielert developed the filter adaptor.

Regulatory decision-makers are also identified: the AD was issued by the Civil Aviation Safety Authority through its Delegate, Charles Lenarcic. The AD therefore binds the specified engine/aircraft population within the jurisdiction of the issuing authority. The AD does not enumerate rights of appeal, exemption processes, or alternative compliance methods inside its text; hence the immediate operational burden falls on operators and maintainers to follow the prescribed SB and meet the prescribed timing.

Secondary stakeholders include aircraft owners whose airframes incorporate the listed EASA STC installations, organisations that provide spare parts and logistics for Thielert engines, and insurers that underwrite aircraft with these engines; the AD’s requirement to retrofit within a short timeframe may affect maintenance scheduling, aircraft availability and planning for affected fleets. The AD does not specify who bears cost or how parts are to be procured, therefore those commercial decisions rest with owners, operators and suppliers.

The AD establishes a single, focused duty: modify the engine oil system by installing the Thielert-designed catchtank (sump) filter adaptor, following the method set out in Thielert TM/SB TAE 125-0016, initial issue dated 19 September 2006, or Revision 1 dated 15 June 2007. This is presented as the required course of action in the AD under the heading “Requirement.” The duty is keyed to the effective date of the AD, 25 October 2007, and the AD sets the compliance deadline as within the next 50 flight hours after the effective date, but not later than 30 November 2007, whichever occurs first after the effective date.

The AD identifies precisely which engines are subject to the duty, thereby defining the duty’s scope: all TAE125-01 engines with serial numbers up to and including s/n 02-01-1018. The AD also lists aircraft types on which these engines are known to be installed, which operationally guides owners and operators to determine whether an airframe must be subject to the duty. The AD does not reproduce or restate the SB content, but by reference makes adherence to the SB a mandatory element of compliance.

The directive text does not set out specific rights such as appeal, alternative compliance routes, or waivers. The AD does not include provisions concerning who must pay or how costs are to be allocated; the requirement is simply stated as an operational mandate. The AD does not specify record-keeping requirements, certification steps, or signatures required to show compliance; it confines itself to ordering the modification and specifying the accepted SB versions and the compliance timeframe. The absence of explicit procedural rights or administrative mechanisms inside the AD means that such matters, if applicable, must be handled through other instruments or agency processes not contained in the text.

The AD also cross-references other regulatory material by noting EASA AD 2007-0232, suggesting that the regulatory action is coordinated with an overseas regulator, and by naming the Thielert SB as the prescriptive technical document. The AD attributes the technical solution to Thielert, stating that Thielert developed the filter adaptor; thereby the practical duty combines regulatory command with manufacturer-prescribed means.

The text of this AD does not include any specific penalties, sanctions, or enforcement mechanics. It records the operative requirement, the applicable engine population, the accepted method of compliance (Thielert TM/SB TAE 125-0016 initial issue or Rev 1), the compliance window, and the effective date, but it does not state fines, administrative penalties, or other enforcement steps within the document itself.

This means that the AD sets out the technical and temporal obligations but leaves any discussion of enforcement, sanctioning or monitoring mechanisms outside its written terms. The AD does show that it was issued by the Delegate of the Civil Aviation Safety Authority, which identifies the issuing authority, but the instrument provided does not describe how compliance will be verified, what enforcement action will follow for non-compliance, or whether there are remedial or appeal procedures specific to this AD. The AD also does not state whether operations are expressly prohibited for non-compliant units or whether alternative actions are acceptable.

Because this directive contains no internal enforcement provisions, a reader seeking enforcement detail must look to the broader regulatory framework or to other CASA instruments for how AD compliance is monitored and enforced. That material is not contained in the AD text provided. The AD’s own terms therefore are limited to specifying what must be done and by when, without specifying within the instrument the penalties or administrative steps that will be taken if the mandatory actions are not carried out.

The AD explicitly cross-references outside material in two ways. First, it references Thielert Aircraft Engines TM/SB TAE 125-0016 (initial issue 19 September 2006 or Revision 1 dated 15 June 2007) as the prescriptive technical standard for the required modification. The SB is therefore integrated into the AD as the operative technical instrument, meaning that the AD’s requirements depend on compliance with a manufacturer-issued technical document. Second, the AD refers to EASA AD 2007-0232 dated 23 August 2007, indicating a corresponding action by the European aviation safety regulator.

The AD lists EASA Supplemental Type Certificate (STC) numbers for aircraft on which the engines are known to be installed; those STC references (for example EASA.A.S.01527 for Cessna 172/F172, EASA.A.S.01632 for Piper PA-28, EASA.A.S.01380 for Robin DR 400) identify the installations that tie the engine AD to particular airframes. The presence of STC numbers and the EASA AD reference indicate alignment with type-approval and STC documentation used in international certification systems.

The AD does not itself state interactions with any national aviation statutes, civil aviation regulations, or enforcement provisions. It does not incorporate or displace other legal instruments in its text; it is framed as a standalone AD that prescribes a specific hardware modification for a defined engine population. In practice, operators will need to consider the AD alongside any continuing airworthiness obligations that arise under their operating certificates and maintenance regulations, and the AD’s reference to an EASA AD suggests parallel regulatory expectations across jurisdictions for the same safety issue. However, the AD text provided does not state how it should be reconciled with other instruments, nor does it provide an explicit statement about its precedence or relationship with other CASA instruments.

In short, the AD interacts with other technical and certification materials by reference to the Thielert technical bulletin and to the EASA AD and STC documentation listed; the AD itself does not include broader legal cross-references or enforcement provisions in the text supplied.

The AD and the technical material it invokes include several dated entries that form the recorded history relevant to this instrument. The manufacturer technical document accepted by the AD is Thielert TM/SB TAE 125-0016. The AD allows compliance via the initial issue of that SB dated 19 September 2006 or via Revision 1 dated 15 June 2007. Thus the SB itself has at least two iterations recognised by the AD.

On the regulatory timeline, EASA issued an AD on the same issue, cited as EASA AD 2007-0232 dated 23 August 2007. CASA’s AD/THIELERT/6 bears the internal reference 11/2007 and was signed by Charles Lenarcic, Delegate of the Civil Aviation Safety Authority, on 13 September 2007. The AD became effective on 25 October 2007. The compliance deadline in the AD ties to both the effective date and a calendar date: compliance is required within the next 50 flight hours after the effective date, but not later than 30 November 2007, whichever occurs first following the effective date.

The AD document presented contains repeated header lines and visual elements, but no subsequent amendments, corrigenda, or revocations are recorded within the instrument as supplied. The AD itself accepts two dated versions of the SB as compliant methods, but it does not list later SB revisions or further AD amendments beyond the initial issuance. The AD therefore records a short, concrete amendment history for the SB and a brief timeline for the regulatory action: initial SB 19 September 2006, SB Revision 1 15 June 2007, EASA AD 23 August 2007, CASA delegate sign-off 13 September 2007, AD effective 25 October 2007, compliance deadline within 50 flight hours or by 30 November 2007.

If a reader requires information on any post-issuance amendments to either the Thielert SB or the AD, or on subsequent AD revocations or extensions, that material does not appear in the AD text provided and must be sourced separately from Thielert or CASA records.

The AD text contains no references to litigation, legal challenges, court decisions, appeals or judicial review related to this directive. The instrument records the safety incident that motivated the AD and sets out the prescriptive requirement, but it does not include any notation of disputes, enforcement actions, administrative appeals, or court matters.

Therefore, based purely on the provided AD text, there is no recorded litigation history connected to AD/THIELERT/6 within the instrument. Any litigation or legal proceedings that may have arisen before or after the AD’s issuance are not recorded or described in this document. Readers seeking to establish whether the AD has been subject to legal challenge or whether there are reported cases interpreting or applying the AD will need to consult court records, administrative tribunal records, or legal reporting outside the AD that is not contained in the supplied text.

The AD contains a number of precise formulations and constraints that can create operational pitfalls if they are not read closely.

Applicability is serial-number specific, and the AD uses inclusive language, "up to and including s/n 02-01-1018." That requires accurate engine serial-number verification; owners/operators who rely on model or airframe type alone risk missing or mis-classifying engines by serial number. The AD lists aircraft types where the engines are known to be installed, but the applicability is limited to engine serial numbers, not to aircraft types per se. Failure to confirm serial numbers could cause either unnecessary modification of unlisted engines or omission of required modification on affected engines.

The compliance timing is a potential source of confusion. The AD requires modification "within the next 50 flight hours after the effective date of this directive, but not later than 30 November 2007, whichever occurs first after the effective date of this AD." The effective date is 25 October 2007. Operators must therefore perform the work by the earlier of 50 flight hours or 30 November 2007. In practical terms, that calendar constraint can be tighter than operators expect if an engine accrues flight hours slowly; conversely, if an engine logs many hours quickly, the 50 flight hour limit may be the binding constraint. Misreading "whichever occurs first" could lead to missing a binding deadline.

The AD mandates compliance "in accordance with Thielert Aircraft Engines TM/SB TAE 125-0016, initial issue dated 19 September 2006 or Revision 1 dated 15 June 2007." This dual acceptance means that operators must ensure they have one of those exact SB versions. Installation to any later revision is not authorised by this AD text unless explicitly accepted elsewhere. Using an alternative procedure, a later SB, or an equivalent modification without an express statement in the AD could result in a failure to comply with the AD as written.

The AD references an EASA AD and lists EASA STC numbers for common installations. These references assist in locating affected airframes; however, the AD does not state how to treat installations that might have been made under different STCs or different certification paths. Operators with non-listed or later STCs should not assume exclusion; the AD is engine-serial-number focused and may therefore apply despite different airframe documentation.

The AD provides no internal statement about enforcement, penalties or extensions. The absence of such language can be mistaken for flexibility; however, the AD nonetheless sets a fixed obligation in its text. Because procedures for sign-off, acceptance or recording compliance are not set out in the AD, operators should be careful to document compliance clearly and to retain the SB used for the modification as the AD references it as the method of compliance.

Finally, the AD notes that Thielert developed the filter adaptor. That creates a commercial link between the required modification and the manufacturer’s parts and procedures. Operators should consider procurement lead times and part availability in meeting the short compliance window; failure to obtain the specified adaptor and follow the exact SB could lead to non-compliance with the AD terms.

The AD prescribes a single route for compliance: install the oil catchtank (sump) filter adaptor in accordance with Thielert TM/SB TAE 125-0016, using either the initial issue dated 19 September 2006 or Revision 1 dated 15 June 2007. Compliance must be completed within the next 50 flight hours after the AD’s effective date (25 October 2007), but not later than 30 November 2007, whichever occurs first after the effective date.

Practical steps that follow directly from the AD text are:

• Confirm whether the engine is within the AD’s applicability by checking the engine serial number. The AD applies to TAE125-01 engines with serial numbers up to and including 02-01-1018. If the engine serial number is beyond that inclusive range, the AD’s language does not apply to that engine as written.

• Obtain the exact Thielert technical material required by the AD, identified as TM/SB TAE 125-0016. The AD permits either the initial issue dated 19 September 2006 or Revision 1 dated 15 June 2007. Use one of those two versions for the modification.

• Schedule and perform the modification within the prescribed timeframe, taking into account the earlier of 50 flight hours after 25 October 2007 or 30 November 2007. The AD sets a hard binding window in its text; completing the installation after that period would be outside the AD’s stated compliance timeline.

• Follow the SB’s procedural steps and parts lists exactly as recorded in the accepted SB version. The AD does not reproduce the SB; it requires that the modification be completed "in accordance with" the SB. Accordingly, the SB will contain the detail necessary to perform the work.

• Document the completion of the modification in the aircraft and engine maintenance records, identifying the SB version used and the date and number of flight hours at completion. The AD itself does not state recordkeeping requirements, but because it names the SB and the compliance window, maintaining contemporaneous evidence that the AD’s requirements were met aligns with the AD’s terms.

• Verify aircraft configuration. The AD lists aircraft types and STC numbers where the engines are known to be installed; confirm that the installation used on the particular airframe corresponds with the engine’s serial number and any STC constraints.

• Retain the SB and any manufacturer correspondence that supports the work performed, because the AD’s compliance method is the manufacturer SB it references.

The AD does not provide alternative methods of compliance within its text, nor does it reference an exemption process or extensions. Accordingly, the path set out is singular: complete the catchtank filter adaptor installation per Thielert TM/SB TAE 125-0016 initial or Rev 1 within the specified timeframe. The AD does reference EASA AD 2007-0232 and the SB’s revision history, so operators may wish to consult those documents for additional context, but the required action for compliance under this AD is to follow the specified SB and timing.