AD/PA-31/129 Amdt 1 - Elevator Structure

The instrument rests on a small set of tightly defined operational concepts: applicability cohorts by model and serial number; mandatory inspection regimes; terminating modifications; interrelationship between different modification actions; and temporal compliance windows keyed to either hours-in-service thresholds or fixed post-issue short windows.

Applicability is explicit and serial-specific. The AD separates affected aeroplanes into three requirement groups with different obligations. Requirement 1 covers early PA-31 and PA-31-300 serials 31-2 to 31-694. Requirement 2 covers a defined set of PA-31P, PA-31T and derivative serial number ranges. Requirement 3 broadens the list to include PA-31, PA-31-300, PA-31-325 in serials 31-2 through 31-8312019, PA-31-350 in specified serial ranges, and PA-31P-350 listed serials (Applicability). The segregation by Requirement group means the same model family can be subject to different mandated actions depending on serial number ranges.

Inspection versus terminating action is a central operational trade-off. Requirement 1.a mandates inspection of rudder and elevator spars and elevator butt ribs per Piper SB No. 323 dated 21 September 1970. Requirement 1.b prescribes replacement of cracked parts if found, either continuing inspections or incorporating Kit No. 760-465. Requirement 1.c requires incorporation of Kit No. 760-465 as terminating action to cease repetitive inspections. Thus the AD creates an interim recurring-inspection path and a separate one-time modification path that terminates the inspection obligation.

The AD references specific manufacturer service documents and kits by number and date. Compliance must be "in accordance with the instructions contained in" the listed SBs and kits (Requirement & Compliance). That means the substantive method, inspection detail, part numbers, and installation procedures are delegated to the Piper documentation cited.

Temporal rules are precise and conjunctive. For inspections, the interval is not to exceed 100 hours time in service until Kit No. 760-465 is incorporated (Compliance 1.a). For kit incorporation, the typical deadline is upon accumulating 2,000 hours total time in service or within 100 hours time in service after 9 August 2001, whichever occurs later (Compliance for 1.c, 2.a/2.b, and 3). These dual thresholds create different practical obligations depending on an aircraft’s current total-time figure at the AD’s effective date.

Interdependencies with other directives and service documents are called out. Note 3 instructs that, where AD/PA-31/126 Amdt 3 also applies to an aircraft affected by Requirement 3, the spar replacement required by AD/PA-31/126 Amdt 3 should, if possible, be done before incorporating Kit 766-642. The AD explicitly states no credit is given for accomplishing Piper SB 864 (Note 3). The Background notes FAA AD 2001-06-01 Amdt 39-12148 as related federal action.

Procedurally, the AD is issued under a CASA delegate’s authority and revokes the previous iteration of AD/PA-31/129 while reissuing the consolidated instrument. Amendment 1 is limited in scope to clarifying the installation interrelationship described in Note 3 (Background).

The Directive directly affects owners, operators, maintenance organisations and certificated maintenance personnel of the specified Piper PA-31 series aeroplanes listed in the Applicability section. For each affected aircraft, the AD prescribes mandatory acts that must be carried out either by appropriately certificated maintenance organisations or persons authorised to perform the work in accordance with Piper SB and kit instructions.

Owners and operators bear the obligation to ensure the actions are taken in the circumstances and at the times specified. The Directive’s Compliance section makes timing mandatory: inspections within 100 hours after the last inspection previously required by AD/PA-31/13 and thereafter at intervals not to exceed 100 hours until Kit No. 760-465 is incorporated (Compliance 1.a); replacement before further flight if cracks are found (Compliance 1.b); incorporation of listed kits upon reaching 2,000 hours total time or within 100 hours after 9 August 2001, whichever occurs later (Compliance 1.c, 2.a/2.b, 3). Those time constraints allocate compliance risk and scheduling obligations to operators with varying utilisation profiles.

Maintenance organisations are affected because the Directive requires work to be performed "in accordance with the instructions contained in" specified Piper Service Bulletins and kit installation instructions (Requirement). Those instructions will dictate inspection techniques, acceptance criteria for cracks, part numbers, installation steps, and any special tooling, so the quality and scope of the required work rests on following the manufacturer’s documents referenced.

Aircraft certificating authorities and inspectors will be responsible for verifying compliance before issuing or renewing certificates of airworthiness. The AD contains an explicit proviso in Note 1 that if the specified modification was complied with before issue of an Australian Certificate of Airworthiness, no further action is required for that aircraft. That note affects new entries on the Australian register and indicates an administrative interaction between compliance records and certification decisions.

Suppliers of parts and kits are affected indirectly through demand for Elevator and Rudder Hinge Replacement Kit No. 760-465, Elevator Trim System Modification Kit No. 760-989, Elevator Butt Rib Refinement Kit No. 766-219, and Elevator Butt Rib Reinforcement Kit No. 766-642. Operators who elect the terminating actions will require kit parts and possibly shop time.

Regulatory decision-makers are the CASA delegate and CASA as the issuing authority. The AD is issued under subregulation 39.1(1) of CAR 1998 and was signed by the delegate, David Alan Villiers, making the actions mandatory and administratively enforceable by CASA (opening paragraph; signature block).

Duties

• Perform inspections: For aircraft subject to Requirement 1, operators must inspect rudder and elevator spars and elevator butt ribs for cracks as specified by Piper SB No. 323 dated 21 September 1970. The inspections are required within 100 hours time in service after the last inspection previously required by AD/PA-31/13 and thereafter at intervals not exceeding 100 hours until Kit No. 760-465 is incorporated (Requirement 1.a; Compliance 1.a).

• Replace cracked parts: If cracks are discovered during any inspection, the cracked rudder or elevator structure part must be replaced, and thereafter the operator must either continue re-inspections per SB No. 323 or incorporate Kit No. 760-465 as specified (Requirement 1.b; Compliance 1.b).

• Incorporate terminating modification: Operators subject to Requirement 1.c, 2.a/2.b, and 3 must incorporate specified kits (760-465, 760-989/766-219, 766-642 respectively) in accordance with the kit and SB instructions. The AD states explicit times for these incorporations, typically upon reaching 2,000 hours total time in service or within 100 hours after 9 August 2001, whichever occurs later (Requirement 1.c; Requirement 2.a/2.b; Requirement 3; Compliance).

• Follow manufacturer instructions: Every mandatory action is to be carried out "in accordance with the instructions contained in" the referenced Service Bulletins and kit manuals (Requirement). That is not optional; the AD establishes the Piper documentation as the means and method for compliance.

• Observe interdependency instructions: For aircraft to which AD/PA-31/126 Amdt 3 also applies, spar replacement required under that other AD should be accomplished, if possible, before installing Kit 766-642 (Note 3). No credit is given for Piper SB 864 (Note 3). Operators must therefore sequence work in accordance with the notes.

Rights and administrative positions

• No-action exemption where already done: Note 1 and Note 2 create limited exemptions from further action when compliance with the named modifications occurred before particular administrative events. Note 1 states that the modification retained from AD 76-03-01, if complied with before issue of an Australian Certificate of Airworthiness, requires no further action. Note 2 says the refinement kit may have been incorporated as specified in SB 897A, in which case no further action is required. Those notes confer a conditional right to avoid repeated work where the required modification is already present.

• No credit for certain SBs: Operators who previously complied with Piper SB 864 are not credited under this AD for that work where Kit 766-642 is required (Note 3). That is a specific denial of a compliance shortcut. The AD thus limits rights to claim prior compliance to those particular SBs and kits expressly accepted.

Delegated authority and revocation

• CASA delegate’s authority: The AD is issued by a CASA delegate and specifically revokes the prior AD/PA-31/129, issuing the updated AD under subregulation 39.1(1) of CAR 1998. The delegate’s exercise of that subregulation imposes binding duties on affected parties.

Method and timing obligations

• "In accordance with" binding method: By tying required actions to the SBs and kit instructions, the AD fixes not only what must be done but how it must be done. The AD requires compliance both substantively and procedurally in accordance with manufacturer documentation.

• Fixed and use-hour-based deadlines: The Compliance section contains both fixed workwindows tied to the AD’s issue date (within 100 hours after 9 August 2001) and cumulative-hours thresholds (2,000 hours total time in service). Operators must track hours-in-service and schedule work accordingly.

The AD is issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998, which the instrument invokes as its legal authority. The text of the AD itself requires that the actions described be taken in the circumstances, in accordance with the instructions, and at the times specified (opening paragraph). These elements create a mandatory regulatory requirement for affected aircraft.

The instrument does not list specific monetary penalties, criminal offences or enforcement processes within its text. It does, however, enact binding obligations under the CAR 1998 framework by the delegate’s signature. Enforcement therefore attaches to the regulatory regime under which the AD is issued. The mechanics of enforcement, such as certificate suspension, grounding orders, infringement notices, or prosecution, are not set out in the AD text itself; instead, they are part of the broader CAR 1998 enforcement machinery invoked by the AD’s authority statement. The AD’s language places a compliance duty on operators to perform inspections, to replace cracked parts before further flight, and to incorporate specified kits at the scheduled times.

Operational enforcement in the field will typically involve validation of compliance by inspectors at maintenance release, airworthiness certification, and surveillance activities. The AD includes instructions that work must be carried out "in accordance with the instructions contained in" the nominated Piper SBs and kit instructions. Non-compliance with those instructions, or with the AD’s timing requirements, would create a regulatory non-conformance under CAR 1998, enforceable by CASA in accordance with its statutory powers. The AD does not itself specify who within CASA enforces compliance, or set out appeal or review routes; it simply records that it is issued by CASA under the cited subregulation and is signed by the delegate (opening paragraph; Background; signature).

The AD also revokes the earlier AD/PA-31/129 and replaces it. The Compliance section explicitly preserves the compliance times of the original issue; it states that the "compliance times of the original issue of this Directive remain unchanged by this issue." That retention of compliance times means that enforcement actions will respect any timelines previously established in the original directive. The AD became effective on 10 October 2001. The delegate’s signature and Gazette notice provide the administrative record that the AD is in force from that date (signature block; final paragraph).

This AD is an instrument issued under the Civil Aviation Regulations 1998, specifically invoking subregulation 39.1(1). As such, it sits within the CAR 1998 regulatory framework rather than as standalone private law. The AD explicitly revokes the previous AD/PA-31/129 and reissues the consolidated directive. It also preserves the compliance times of the original issue, stating those times "remain unchanged" (Compliance). The AD itself does not purport to amend primary legislation; it imposes regulatory obligations under the power delegated by CAR 1998.

Inter-AD interactions are specifically addressed. Note 3 warns of an installation interrelationship with AD/PA-31/126 Amdt 3, directing that the spar replacement required by AD/PA-31/126 Amdt 3 should, if possible, be done before incorporating Kit 766-642. The AD also explicitly states "No credit is given for accomplishing Piper SB 864" in the context of Kit 766-642 applicability (Note 3). These provisions create a sequence constraint where compliance with one AD (AD/PA-31/126 Amdt 3) can affect the practical order in which work required by this AD is performed. They also deny the possibility of substituting certain service bulletin compliance as satisfying the AD’s requirements.

The Background references FAA regulatory action, noting FAA AD 2001-06-01 Amdt 39-12148 as a related document. The Background states that FAA policy of incorporating modifications that terminate repetitive inspections prompted the FAA AD, which superseded three existing FAA ADs and was reflected in CASA Directives. In consequence, this Directive consolidates the inspection requirements of previously issued Directives and requires terminating action for the inspections. That description places this AD in a trans-jurisdictional regulatory alignment posture with FAA actions, insofar as CASA has adopted the FAA’s substantive approach by consolidating and requiring terminating modifications.

Administrative and certification interactions are implicit. Note 1 says that if the modification retained from AD 76-03-01 was complied with before the issue of an Australian Certificate of Airworthiness, no further action is required. That creates an administrative interface between AD compliance and the civil aircraft certification process, by granting an exemption where the work was done prior to initial Australian certification.

The AD references specific Piper Service Bulletins and kit installation instructions as the method for compliance. These manufacturer documents form part of the technical compliance regime and therefore interact with the AD’s legal requirements; work done in accordance with the SBs and kits is prescribed by the AD as the compliant method. That linkage means compliance depends both on CASA as the regulatory issuer and on the manufacturer’s manuals as the technical instructive source.

The AD document includes two delineated historical points: the original issue date and this Amendment 1. The AD states that the original issue of this Airworthiness Directive became effective on 9 August 2001. Amendment 1 is then issued and becomes effective on 10 October 2001. The opening paragraph indicates the delegate has revoked Airworthiness Directive AD/PA-31/129 and issued the following AD under subregulation 39.1(1) of CAR 1998, showing that the amendment replaces the previous text (opening paragraph; final paragraphs).

Amendment 1’s explicit purpose is narrow. The Background explains that Amendment 1 is issued "to clarify, as Note 3, the installation interrelationship between the elevator spar and the butt rib reinforcement kit, following information received from the manufacturer." That identifies Amendment 1 as a clarification rather than the imposition of new substantive requirements beyond the clarification. The AD text therefore contains the revised Note 3, which instructs sequencing of the spar replacement required by AD/PA-31/126 Amdt 3 before incorporating Kit 766-642 where possible, and makes clear that no credit is given for Piper SB 864 (Note 3).

The Background also situates the AD within a prior FAA-driven policy change. It says the FAA policy of incorporating modifications, when available, that will terminate the need for repetitive inspections prompted FAA AD 2001-06-01, which superseded three existing FAA ADs; these were reflected in CASA Directives. This Directive consolidates the inspection requirements of previously issued Directions and requires terminating action for the inspections (Background). That history indicates the AD is part of a consolidation and termination policy stream, and Amendment 1 clarifies interdependency matters in that consolidated instrument.

Administrative finalisation is recorded. The AD is signed by David Alan Villiers as the Delegate of the Civil Aviation Safety Authority on 4 October 2001. The AD is notified in the Commonwealth of Australia Gazette on 10 October 2001. The AD identifies the earlier ADs and service bulletins it supersedes or retains in effect by cross-reference (opening paragraph; Background; signature block; Gazette notice).

The instrument does not include any court or tribunal decisions, appeals, or judicial annotations. The AD text contains no references to litigation having been commenced, resolved, appealed or otherwise adjudicated in relation to AD/PA-31/129 or its Amendment 1. The Background attributes the change of approach to FAA policy and manufacturer-provided information but does not record any legal challenges to the AD or to the FAA action it references.

Because no litigation history is provided in the AD, there is no textual record in this instrument of judicial interpretation of its terms, of challenges to the legal basis in subregulation 39.1(1) of CAR 1998, or of disputes over technical compliance matters such as interpretation of the referenced Piper Service Bulletins and kit instructions. The AD therefore stands, within the four corners of its text, as an administrative exercise of regulatory power by a CASA delegate, not as a document that records or summarises judicial proceedings.

In practice, the absence of litigation history in the AD means any contested points arising from the AD would need to be sought in external legal records, tribunal files or CASA enforcement records. This instrument itself contains only the substantive requirements and clarifying notes and does not narrate any dispute resolution outcomes. Where other ADs are cross-referenced (for example AD/PA-31/126 Amdt 3 and FAA AD 2001-06-01), those documents may themselves have histories outside this AD, but none are recorded here.

Given that no litigation or adjudicative outcomes are included, readers must rely solely on the AD text, its Notes and the referenced Piper SBs and kit instructions for authoritative obligations and technical guidance. Any legal challenges or administrative reviews that might subsequently arise are not reflected in this document.

Several practical pitfalls and points of possible confusion are embedded in the AD’s structure and wording, and they can affect compliance planning, scheduling and the interpretation of prior work.

1. Serial-number specific applicability and requirement grouping. The AD divides affected aeroplanes into three separate Requirement groups with different obligations. The same model family appears across multiple Requirement groupings with differing serial number ranges. Operators must match exact serial numbers to the lists provided in the Applicability section to determine which Requirement(s) apply. Misclassification by model alone will not suffice because the AD is serial-specific.

2. Dual deadlines can cut either way. Many kit incorporations are required "upon accumulating 2,000 hours total time in service or within 100 hours time in service after 9 August 2001, whichever occurs later" (Compliance). For aircraft already above 2,000 hours at the AD date, the kit incorporation is immediately due. For low-utilisation aircraft, the 100-hour post-9 August 2001 window may allow delay until the 2,000-hour threshold is reached. Operators must track total hours precisely to determine which trigger applies for their aircraft.

3. Immediate grounding risk on discovery of cracks. Requirement 1.b requires replacement of cracked rudder or elevator structure parts "before further flight." That phrasing creates an operational constraint: if an inspection uncovers a crack, the aircraft cannot undertake further flight until replacement is done, or until the operator incorporates the terminating kit per the specified process. That can cause unexpected downtime and may require urgent access to parts and maintenance capacity.

4. No credit for SB 864 and sequencing with other ADs. Note 3 explicitly states "No credit is given for accomplishing Piper SB 864" and instructs that, where AD/PA-31/126 Amdt 3 applies, the spar replacement required by that AD should, if possible, be done before incorporating Kit 766-642. Operators who previously completed SB 864 cannot rely on that as compliance for Kit 766-642. Furthermore, sequencing constraints may force additional disassembly or rework if the order is not observed.

5. Manufacturer instructions are normative. Each Requirement requires work "in accordance with the instructions contained in" the cited SB or kit instructions. The AD therefore makes adherence to those documents the legal method of compliance. If those documents are superseded or if a maintenance provider uses an alternative method, the AD text does not provide latitude; compliance must follow the specified instructions.

6. Legacy compliance exceptions are narrow. Notes 1 and 2 create limited exceptions where specified earlier modifications were performed before the issue of an Australian Certificate of Airworthiness or where SB 897A was previously incorporated. These exceptions are conditional and narrowly drawn. Operators should not assume broad grandfathering beyond the explicit statements in those notes.

7. Consolidation does not remove earlier compliance times. The Compliance section states that "the compliance times of the original issue of this Directive remain unchanged by this issue." Amendment 1 clarifies a Note, but does not alter prior timeframes. Operators cannot assume that the amendment relaxed deadlines.

8. Document dating matters. The AD references specific dated SBs and kit revisions, for example SB No. 323 dated 21 September 1970, Kit No. 760-465 revised 25 October 1989, SB 477A dated 3 November 1975, SB 897B dated 15 July 1997, and SB No. 1008 dated 30 September 1997. Compliance requires reference to these specific documents and versions as the AD prescribes. Using an earlier or later revision of a kit or SB without explicit recognition in the AD may leave an operator uncertain about compliance.

9. Record and certification interactions. The AD notes that certain pre-certification work negates further obligation (Note 1). This interacts with the aircraft’s certification history. Operators registering an imported aircraft, or those that have had work done overseas, must ensure their compliance records clearly establish the timing of modifications relative to the Australian Certificate of Airworthiness issuance date.

This AD ties compliance to specific aircraft, documented procedures and fixed timing thresholds. The following stepwise checklist is derived from the Requirement and Compliance sections and the associated Notes. Each action should be performed "in accordance with the instructions contained in" the referenced Piper Service Bulletins and kit installation instructions.

1. Determine applicability. Identify the aircraft model and exact serial number and map it to the Applicable Requirement group in the Applicability section. The AD differentiates Requirement 1, Requirement 2, and Requirement 3 by precise serial ranges (Applicability). Only aircraft listed in the relevant serial number ranges for each Requirement are subject to that Requirement.

2. For aircraft subject to Requirement 1:

   • Perform inspections of rudder and elevator spars and elevator butt ribs for cracks per Piper SB No. 323 dated 21 September 1970. These inspections must occur within 100 hours time in service after the last inspection previously required by AD/PA-31/13, and thereafter at intervals not to exceed 100 hours until Kit No. 760-465 is incorporated (Requirement 1.a; Compliance 1.a).
   • If cracks are found during an inspection, replace the cracked part and either continue inspections per SB No. 323 or incorporate Elevator and Rudder Hinge Replacement Kit No. 760-465 as specified (Requirement 1.b; Compliance 1.b). Any aircraft with a cracked part must not fly further until the cracked part is replaced (Requirement 1.b).
   • Incorporate Elevator and Rudder Hinge Replacement Kit No. 760-465 in accordance with the kit instructions revised 25 October 1989 as terminating action. The deadline is upon accumulating 2,000 hours total time in service or within 100 hours time in service after 9 August 2001, whichever occurs later (Requirement 1.c; Compliance 1.c).

3. For aircraft subject to Requirement 2:

   • Modify the elevator trim tab system and elevator control tube using Elevator Trim System Modification Kit No. 760-989, as referenced in Piper SB No. 477A dated 3 November 1975 (Requirement 2.a).
   • Incorporate Elevator Butt Rib Refinement Kit No. 766-219 in accordance with the kit instructions as referenced in Piper SB No. 897B dated 15 July 1997 (Requirement 2.b).
   • Timing: Both 2.a and 2.b must be accomplished upon accumulating 2,000 hours total time in service or within 100 hours time in service after 9 August 2001, whichever occurs later (Compliance 2.a and 2.b).
   • Note 1 applies: If the modification retained from AD 76-03-01 was complied with before issue of an Australian Certificate of Airworthiness, no further action is required for that aircraft (Note 1).

4. For aircraft subject to Requirement 3:

   • Incorporate Elevator Butt Rib Reinforcement Kit No. 766-642 per the kit instructions referenced in Piper SB No. 1008 dated 30 September 1997 (Requirement 3).
   • Timing: Incorporation required upon accumulating 2,000 hours time in service or within 100 hours time in service after 9 August 2001, whichever occurs later (Compliance 3).
   • If AD/PA-31/126 Amdt 3 also applies to the aircraft, plan to perform the spar replacement required by that AD before incorporating Kit 766-642, if possible, as per Note 3. Do not assume prior compliance with Piper SB 864 satisfies this AD (Note 3).

5. Use the exact SBs and kit revisions cited. The AD requires that actions be taken "in accordance with the instructions contained in" the named SBs and kits. Obtain the specific editions and revisions cited in the AD text (e.g. SB No. 323 dated 21 September 1970; Kit No. 760-465 revised 25 October 1989; SB 477A dated 3 November 1975; SB 897B dated 15 July 1997; SB No. 1008 dated 30 September 1997) and perform work per those documents.

6. Address aircraft with prior modifications. If the aircraft already incorporated the refinement kit as specified in Piper SB 897A, Note 2 says no further action is required for that element. If the specified modification was done prior to the issue of an Australian Certificate of Airworthiness, Note 1 relieves that aircraft from further action in respect of that modification.

7. Schedule and parts. Anticipate that discovery of cracks requires replacement "before further flight" and that kit incorporations will require parts, shop time and possible downtime. Plan logistics to obtain kits No. 760-465, 760-989, 766-219 and 766-642 where applicable.

8. Maintain a clear audit trail. While the AD text does not prescribe record-keeping language, the AD ties compliance to specific documented procedures and asks that actions be taken in accordance with the referenced instructions. Keep documentation of inspections, findings, part replacements, kit installations and references to the exact SB and kit revisions used, so that compliance can be demonstrated to CASA inspectors or during certification processes, particularly where Notes provide exemptions based on pre-existing work dates.

9. Coordinate sequencing with other ADs. Where AD/PA-31/126 Amdt 3 applies, sequence the spar replacement before fitting Kit 766-642 where possible, to avoid rework or non-compliant installations (Note 3).

10. Confirm effective dates and retained timeframes. The AD became effective on 10 October 2001 and states that the compliance times of the original issue remain unchanged. Ensure any scheduling respects those retained deadlines (final paragraphs; Compliance).

Following these steps will align an operator’s maintenance and modification programme with the mandatory acts prescribed by AD/PA-31/129 Amdt 1. The AD’s repeated instruction to follow the precise manufacturer documentation means compliance cannot be achieved by informal inspection methods or by relying on unreferenced alternative procedures.