AD/PA-31/126 Amdt 3 - Elevator Spar

The directive rests on a small set of mechanistic concepts that determine operator obligations and regulatory outcomes.

Unsafe condition and legal basis: CASA issues the AD under CAR 1998 subregulation 39.1(1) to correct an identified unsafe condition (opening paragraph). The AD revokes AD/PA‑31/126 Amdt 1 and issues amended requirements (first paragraph).

Applicability: The AD is limited to explicitly enumerated models and serial-number ranges (Applicability). This is a conventional AD scope: it binds only the aircraft listed.

Inspection regimes: Operators may comply by following one of two inspection approaches set out in the Requirement section. Requirement 1 is an on‑aircraft visual inspection sequence: 1.a directs a visual inspection of the upper and lower surfaces of the elevator spar from outboard hinge to 9 inches (230 mm) inboard for cracking, loose rivets and fretting; 1.b requires detail visual inspection of rear faces of spar webs at inboard ends of outboard hinge doublers and forward faces at their outboard ends (with emphasis on bend radii) (Requirement 1.a and 1.b). Requirement 2 prescribes installing inspection access holes per MSB 998A and using a boroscope for inspection (Requirement 2).

Replacement obligation and improved parts: Requirement 3 mandates replacement of each elevator or elevator spar assembly with a part of improved design as specified by the “Replacement Elevator P/N” and “Replace Spar P/N” columns in the Material Required Table on page 4 of Piper MSB 998A, and that replacement be accomplished in accordance with the applicable maintenance manual (Requirement 3). If cracks are found, replacement is required before further flight (Compliance 3).

Repetitive inspection cadence and thresholds: The AD sets repetitive inspection intervals not to exceed 100 hours time in service for ongoing visual or boroscope inspections (Compliance 1.b and 2.b). It also establishes replacement deadlines linked to either discovery of cracks or elapsed component hours (for example, replacement within 1,000 hours time in service after specified inspections) (Compliance 3).

Ancillary inspection: Requirement 4 requires inspection of elevator ice protection boots for looseness in accordance with MSB 998A instructions and mandates reinstall or replace before further flight if loose (Requirement 4).

Authorisations and approvals: Note 1 permits installation of access holes “in accordance with a scheme approved by a CAR 35 authorised person” to facilitate access for inspections, signalling an approval gate for structural modifications that are not unlimited (Note 1). The AD also cross‑references FAA AD 99‑12‑05 (Note 2).

Amendment interactions: The AD explicitly preserves earlier compliance timings from prior issues except for the Requirement 3 compliance timing change, and Amendment 3 clarifies Compliance 3 and Note 3 (Compliance section and Background).

The AD therefore combines a mandatory inspection regime, an option to adopt an access‑hole/boroscope method, and finality via replacement with improved‑design parts when cracking exists or when fixed hours have elapsed. All work must be carried out in accordance with Piper MSB 998A instructions and the applicable maintenance manual, and particular approvals are required for structural access modifications.

Primary affected parties are owners, operators and maintenance providers for the listed PA‑31 series aeroplanes and the organisations that certify maintenance and modifications on those aircraft.

Aircraft operators and owners: The AD applies to the specific PA‑31 family aeroplane serial numbers listed under Applicability. Owners/operators of aircraft within those serial ranges must implement the inspections, boroscope access hole installations, repetitive inspections, and any replacements or boot repairs mandated by the AD. Where cracks are discovered, replacement “before further flight” is mandatory (Compliance 3), imposing immediate operational impact and potential unplanned maintenance downtime and cost.

Maintenance organisations and mechanics: The AD requires detail visual inspections (Requirement 1.b) and, if chosen, installation of access holes and boroscope inspections in accordance with Piper MSB 998A (Requirement 2). Maintenance personnel must follow the Instructions section of MSB 998A and the applicable maintenance manual for replacements (Requirement 3). The AD also requires that replacement parts be of the improved design and specific part numbers listed in MSB 998A’s Material Required Table (Requirement 3), so maintainers must source the correct parts and apply the maintenance manual procedures.

Certifying and approval authorities: Installation of access holes must be “in accordance with a scheme approved by a CAR 35 authorised person” (Note 1), so CAR 35 authorised persons who approve minor/major modifications will be engaged to approve access‑hole schemes. CASA, via its delegate, is the issuing and enforcement authority; the AD was issued by the CASA delegate and notified in the Commonwealth Gazette (final lines).

Manufacturers and parts suppliers: Piper’s Mandatory Service Bulletin (MSB) 998A is central. Parts suppliers that stock the improved elevator or spar assemblies specified by the MSB will be the source of replacement parts. The AD mandates using the P/Ns in the Material Required Table on page 4 of MSB 998A (Requirement 3). Suppliers and distributors therefore may see demand for replacement parts where operators opt to replace rather than continue inspections.

Operational planners and air operators’ maintenance programmes: Repetitive inspection intervals (every 100 hours time in service) and replacement deadlines require operators to adjust maintenance planning, scheduling and budgeting. There is also an administrative requirement to track component time in service to determine when the mandatory replacements fall due (Compliance). If cracks are discovered, aircraft may be grounded pending replacement “before further flight” (Compliance 3), affecting utilisation and potential revenue for commercial operators.

Legal and compliance advisers: Compliance with the AD requires interpretation of the interplay between historic compliance dates and current actions (the AD preserves prior compliance times except for Requirement 3). Advisers will need to ensure maintenance records demonstrate adherence to the precise timings and methods set out in the AD and in MSB 998A.

Who pays: The AD imposes inspection and replacement costs on the aircraft owner/operator. Costs include labour for repetitive inspections, potential boroscope and access‑hole work (plus CAR 35 approval where an access‑hole scheme is used), parts purchase (replacement elevator or spar assemblies of improved design), and the opportunity cost of aircraft downtime when replacement is required “before further flight” (Requirements and Compliance).

In short, the AD places recurring inspection duties, potential structural modification and replacement obligations, and associated costs and scheduling burdens on operators and maintenance providers for the enumerated PA‑31 aircraft, with approvals required from a CAR 35 authorised person for access‑hole installations and CASA as the issuing authority.

The AD establishes clear mandatory duties and a few bounded choices for how to comply. Duties are expressed as Requirements 1-4 and the Compliance section; rights are limited to the choice between inspection pathways and the option to continue repetitive visual inspections rather than immediate replacement (as described in the Background).

Primary duties

• Perform the inspections specified in either Requirement 1 or Requirement 2. Requirement 1 includes: a visual inspection of the upper and lower surfaces of the elevator spar from the outboard hinge to 9 inches (230 mm) inboard for skin cracking, loose rivets and fretting (Requirement 1.a), and detail visual inspections of rear faces of the left and right elevator spar webs at the inboard ends of the outboard hinge doublers and forward faces at their outboard ends with attention to spar bend radii (Requirement 1.b).

• Alternatively, install access holes and perform boroscope inspections per Piper MSB 998A (Requirement 2). The AD requires that these actions be “in accordance with the Instructions section of Piper Mandatory Service Bulletin (MSB) 998A, dated August 4 1997” (Requirement 2).

• Replace any elevator or elevator spar assembly where cracks are found with a part of improved design specified in MSB 998A’s Material Required Table, and accomplish replacement per the applicable maintenance manual (Requirement 3).

• Inspect elevator ice protection boots for looseness in accordance with MSB 998A and reinstall or replace boots if loose before further flight (Requirement 4).

Timing duties and inspection cadence

• Initial Requirement 1.a must be performed within 10 hours time in service after 12 October 1995 unless already performed (Compliance 1.a). Requirement 1.b must be done before further flight if cracking, loose rivets, or fretting are found during Requirement 1.a; otherwise before 2,500 hours component time in service or within 100 hours time in service after 20 October 1995, whichever occurs later; thereafter at intervals not to exceed 100 hours time in service until replacement with improved parts (Compliance 1.b).

• Requirement 2: install access holes and do the boroscope inspection upon accumulating 2,500 hours time in service on each elevator spar assembly, or within 100 hours time in service after 31 December 1999, whichever occurs later; thereafter reinspect at intervals not to exceed 100 hours time in service until replacement (Compliance 2).

• Requirement 3: replacement must occur before further flight if cracks are found; otherwise within 1,000 hours time in service after the first Requirement 2 inspection performed after 31 December 1999 or within 1,000 hours time in service after the next Requirement 1 inspection after 24 February 2000, whichever occurs first (Compliance 3).

• Requirement 4: inspect boots within 100 hours time in service after 31 December 1999 unless already accomplished (Compliance 4).

Discretion and limited operator choices

• Operators have a structured choice: comply via frequent visual inspections (Requirement 1) or adopt the access‑hole/boroscope method (Requirement 2). The Background explicitly notes the repetitive visual inspection requirement is retained as an option for operators (Background).

• There is an approval gate: access holes installed to facilitate inspections must follow a scheme approved by a CAR 35 authorised person (Note 1). This limits unfettered modification and places a certification burden on operators who choose Requirement 2.

Obligations triggered by findings

• If any cracks are discovered, immediate duty is to replace the affected spar assembly with an improved‑design part before further flight (Requirement 3 and Compliance). Where one spar is replaced because of a crack, the other spar must still be inspected every 100 hours until replaced at 1,000 hours after the initial inspection or until a crack is found, whichever occurs first (Requirement 3, paragraph following replacement instructions).

Record and method reliance

• The AD requires work to be done “in accordance with the Instructions section of Piper MSB 998A” and with the applicable maintenance manual for replacements (Requirements 2 and 3). This makes adherence to MSB 998A an express procedural duty; operators cannot substitute an alternative repair or replacement method absent approval.

Rights and limited flexibilities

• The main right afforded to operators is the ability to choose one of the two inspection methodologies, and to continue the repetitive visual inspections as an option , the AD preserves that option (Background). For repaired spars prior to Amendment 2, Note 3 permits inspection intervals of 100 hours unless otherwise approved by the Authority, implying an avenue for alternative arrangements subject to CASA approval.

In summary, the AD imposes concrete, non‑discretionary duties to inspect, to replace when cracking exists or when specified hours elapse, to follow MSB 998A and maintenance manual instructions, and to obtain CAR 35 approval for access‑hole schemes. Operators retain the limited choice between two inspection approaches and may seek Authority approval for departures where Note 3 contemplates prior repairs.

The AD is issued as a regulatory instrument under CAR 1998 subregulation 39.1(1) and is therefore an enforceable airworthiness directive within the Australian regulatory regime. The document itself does not list monetary penalties or criminal sanctions; it sets mandatory technical obligations and compliance timings that, if not met, leave an aircraft non‑compliant with the AD and potentially non‑airworthy under CAR standards.

Enforcement authority and notification

• The AD is issued by a CASA delegate and was notified in the Commonwealth of Australia Gazette (final lines). CASA is the regulator responsible for issuing and enforcing airworthiness directives, and the AD’s legal force derives from CAR 1998 subregulation 39.1(1) (opening paragraph). The CASA delegate revoked AD/PA‑31/126 Amdt 1 and issued this amendment (first paragraph), demonstrating the administrative power to revise ADs.

Regulatory consequences of non‑compliance

• The AD prescribes actions “that the delegate considers necessary to correct the unsafe condition” and sets firm timing requirements such as “before further flight” where cracks are found (opening paragraph, Requirement 3, Compliance). Operating an aircraft subject to this AD without having complied with the specified inspections and replacements would mean the aircraft is operated in contravention of the AD and, depending on CAR provisions, may be considered not airworthy. The document does not specify the exact sanctions for non‑compliance; however, non‑compliance typically exposes operators to regulatory enforcement action by CASA consistent with the CAR framework.

Operational enforcement mechanics

• The AD’s operational enforcement derives from inspection, record checks and airworthiness certification processes. Maintenance records must show inspections performed in accordance with the AD and MSB 998A. Required actions before further flight (for example, replacement when cracks are found) create immediate operational constraints: an aircraft with cracked spar discovered during inspection cannot legally be dispatched until the mandated replacement is carried out.

Approvals and discretionary enforcement

• The AD requires certain approvals for modifications: access holes must be installed “in accordance with a scheme approved by a CAR 35 authorised person” (Note 1). If a CAR 35 authorised person’s approval is required but not obtained, the modification will not meet the AD’s stated method, leaving the operator non‑compliant.

Cross‑jurisdictional reference

• The AD notes FAA AD 99‑12‑05 Amdt 39‑11189 (Note 2). While this places the Australian directive in dialogue with a corresponding FAA action, the Australian AD is the enforceable instrument for aircraft subject to Australian jurisdiction. Non‑Australian operators must consider their own national authority’s treatment; this AD itself does not create direct foreign enforcement.

Statutory silence on penalties

• The AD text does not enumerate specific fines, licence suspensions, or criminal offences. Any penalties would be those available to CASA under the Civil Aviation Regulations and applicable enforcement policies. The absence of penalty figures in the AD means operators must consult CAR enforcement provisions and CASA guidance to understand potential sanctions for breaches.

In sum, the AD imposes mandatory obligations enforced by CASA within the CAR framework, with immediate operational consequences for non‑compliance (for example, inability to fly where replacement is required “before further flight”), an approval gate for certain modifications, and notification via the Commonwealth Gazette. The AD itself does not set out monetary penalties or criminal sanctions; those follow from the wider regulatory enforcement regime.

This AD is part of the airworthiness regulatory regime and explicitly references other regulatory instruments and industry documents it must be read alongside.

Statutory basis and national framework

• The AD is issued under CAR 1998 subregulation 39.1(1) (opening paragraph). That locates this instrument within the Civil Aviation Regulations architecture, meaning compliance with the AD is part of the statutory airworthiness obligations imposed by the CAR.

Interaction with maintenance approvals

• Note 1 requires that installation of access holes be performed “in accordance with a scheme approved by a CAR 35 authorised person.” CAR 35 authorisations relate to persons approved to carry out specific maintenance or modification approval activities; the AD therefore overlays individual work instructions with a requirement for a certified approval where structural access holes are installed, tying technical compliance to the authorised‑person approval regime.

Referencing manufacturer service information

• The AD repeatedly mandates that certain actions be “in accordance with the Instructions section of Piper Mandatory Service Bulletin (MSB) 998A, dated August 4 1997” and that replacements be accomplished “in accordance with the applicable maintenance manual” and using P/Ns stated in MSB 998A’s Material Required Table (Requirements 2 and 3). That makes MSB 998A and the maintenance manual integral compliance instruments and signals that operator obligations are to be executed via manufacturer‑specified methods.

Connection to foreign ADs

• The AD expressly refers to FAA AD 99‑12‑05 Amdt 39‑11189 (Note 2) and states in Background that Amendment 2 was issued in response to an FAA AD which introduced inspections and replacement with improved design parts. While FAA ADs are not Australian law, this cross‑reference demonstrates regulatory alignment and that the CASA action adopted similar corrective measures. Operators that fly under foreign registries should note the AD’s reference to related FAA action but must comply with the Australian AD when operating Australian‑registered aircraft.

Continuity with prior ADs and amendments

• The text revokes AD/PA‑31/126 Amdt 1 and makes explicit that the compliance times of the previous issue “remain unchanged by this issue of the Directive, except for the Requirement 3 compliance” (Compliance). Amendment 3 clarifies the intent of Compliance 3 and Compliance Note 3 (Background). As such, the AD interacts with and modifies obligations created by earlier AD amendments; operators must read the AD alongside its amendment history to understand current obligations.

Operational and certification consequences

• The AD’s “before further flight” prescriptions and the requirement to use improved‑design parts per MSB 998A tie into airworthiness certification, release‑to‑service and maintenance sign‑off obligations under the CAR. Non‑compliance with the AD will affect an aircraft’s legal airworthiness and the ability of certificated maintenance release holders to issue a release to service consistent with CAR obligations.

Approval and alternative methods

• Note 3 affords some discretion for spars repaired prior to Amendment 2: they “shall be inspected at intervals not exceeding 100 hours time in service unless otherwise previously approved by the Authority.” This provision provides a statutory mechanism for CASA to approve alternative maintenance regimes or special conditions, but only through express Authority approval.

Recordkeeping and Gazettal

• The AD was notified in the Commonwealth Gazette on 27 January 2000 (final lines). Gazettal is the formal public notification step for such regulatory instruments and interfaces with administrative law requirements for promulgation. Operators’ legal obligation to comply begins with the AD’s effective dates and the compliance schedule set out; recordkeeping of work performed in accordance with MSB 998A and maintenance manuals will be central to demonstrating regulatory compliance in audits or enforcement proceedings under the CAR.

In short, the AD operates within the CAR regulatory framework, references and requires manufacturer service information and parts, depends on CAR 35 authorised person approvals for certain modifications, aligns with FAA action by reference, and modifies prior AD obligations while providing a narrow route to CASA approvals for alternative arrangements.

The AD document itself summarises its own amendment lineage. The history shows staged responses to the safety problem and procedural changes to inspection methodology over time.

Original issue (effective 12 October 1995): The original AD/PA‑31/126 was issued and became effective on 12 October 1995 (final lines). That original issue contained inspection requirements that were subsequently revised by later amendments.

Amendment 1: Amendment 1 removed the prior requirement to perform X‑ray inspections and introduced a visual inspection regime that is described in this AD as maintaining “equivalent safety by mandating a simpler inspection that can be performed more frequently.” Amendment 1 also introduced a threshold for inspection based on a survey of defect reports and revised Figure 1 to provide clearer guidance on inspection location (Background). The AD notes Amendment 1 was revoked by the present instrument (first paragraph states the delegate revokes AD/PA‑31/126 Amdt 1 and issues this AD).

Amendment 2 (effective 31 December 1999): Amendment 2 was issued in response to FAA AD 99‑12‑05 and introduced certain inspections and the option (or requirement in some scenarios) to replace elevators or elevator spar assemblies with parts of improved design, either at a specific time or when cracks are found, whichever occurs first. The repetitive visual inspection requirement from the previous issue remained as an option for operators. The document states Amendment 2 became effective on 31 December 1999 (Background).

Amendment 3 (this document, effective 24 February 2000): Amendment 3 is issued “to clarify the intent of Compliance 3 and Compliance Note 3.” This amendment becomes effective on 24 February 2000 (one of the closing lines). The Compliance section of this AD clarifies the sequence and timing for replacement following inspections and preserves compliance times from prior issues except for the Requirement 3 compliance (Compliance). The AD also notes that the original issue became effective on 12 October 1995 and that Amendment 2 became effective on 31 December 1999 (Background).

Notational history within the AD: The AD carries three Notes that record interactions with other documents and provide conditional language. Note 1 permits installation of access holes “in accordance with a scheme approved by a CAR 35 authorised person.” Note 2 refers to FAA AD 99‑12‑05 Amdt 39‑11189. Note 3 addresses elevator spars repaired prior to Amendment 2, requiring 100‑hour inspection intervals unless otherwise approved by the Authority (Compliance).

Practical effect of the amendments: The amendment sequence shows a transition from heavier NDT (X‑ray) in the original issue to more frequent visual inspections (Amendment 1), then alignment with FAA guidance to provide for replacement with improved parts on a time‑or‑event basis while retaining the visual inspection option (Amendment 2), and finally a clarification of replacement timing and inspection treatment for older repairs (Amendment 3).

Gazettal and delegation: The AD as amended was signed by the CASA delegate Eugene Paul Holzapfel on 12 January 2000 and was notified in the Commonwealth Gazette on 27 January 2000, with the Amendment 3 effective date recorded as 24 February 2000 (closing lines). The document thus records both administrative signature and public notification steps for the amendment history.

The AD text does not reference any litigation, court proceedings or administrative appeals, and it does not name any legal decisions. There are no cases or judicial outcomes recorded in the document itself.

What the AD records instead is administrative action: the CASA delegate’s revocation of AD/PA‑31/126 Amdt 1 and issuance of this amended AD under CAR 1998 subregulation 39.1(1) (opening paragraph). The document provides a technical and administrative history (original issue date, Amendment 1, Amendment 2 and Amendment 3), and notes interactions with FAA AD 99‑12‑05, but does not report any disputes or contested enforcement actions.

Practically, absence of litigation in the AD means that to find a judicial or appellate record concerning this directive one would need to search external case law or administrative records. The AD itself includes only the regulatory text, compliance requirements, the background explanation for the safety concern (numerous reports of cracked spars and instances of severance causing reduced elevator stiffness and risk of tailplane flutter), and the amendment chronology; it does not summarise or indicate any legal challenges or decisions arising from contested enforcement or interpretation.

Therefore, based solely on this source, there is no litigation history recorded or disclosed in the AD.

This AD contains several practical traps for operators and maintenance personnel because of cross‑references to historical dates, the interplay between inspection options, approval gates, and precise timing language.

Historic compliance dates remain in force: The Compliance section preserves some historic time windows from earlier versions of the AD. For example Requirement 1.a requires an inspection “within 10 hours time in service after 12 October 1995, unless previously accomplished in accordance with the previous issues of this Directive” (Compliance 1.a). Despite Amendment 3 being effective 24 February 2000, historic deadlines remain embedded. Operators must carefully map component hours and prior work to determine whether those historic compliance windows have been met or remain applicable, because the AD explicitly states “The compliance times of the previous issue of this Directive remain unchanged by this issue of the Directive, except for the Requirement 3 compliance.” That language can cause confusion if records are incomplete about inspections taken under prior amendments.

Complex replacement timing: The timing for mandatory replacement (Compliance 3) is conditional and uses alternative triggers: replacement must occur “before further flight” if cracks are found; otherwise replacement must occur within 1,000 hours time in service after the first Requirement 2 inspection performed after 31 December 1999 or within 1,000 hours time in service after the next Requirement 1 inspection after 24 February 2000, as applicable. Operators must track which inspection regime was used and when the “first” or “next” such inspection occurred to calculate the 1,000‑hour replacement deadline. Misinterpreting which inspection starts the 1,000‑hour clock is a likely operational pitfall.

One‑spar replacement does not eliminate inspection duty for the other: If one elevator spar assembly is replaced before further flight because a crack is found, the AD still requires that “the other elevator spar assembly must still be repetitively inspected every 100 hours time in service until replacement at 1,000 hours time in service after the initial inspection or when cracks are found, whichever occurs first.” This creates an asymmetric obligation where replacing one damaged component immediately transfers an inspection cadence and future replacement obligation on the mate spar; operators must ensure recordkeeping reflects this remaining inspection obligation.

Access‑hole approvals and modification scope: Note 1 permits installation of access holes “in accordance with a scheme approved by a CAR 35 authorised person.” Operators who install access holes without the required approval risk non‑compliance, because the AD specifically conditions such access‑hole schemes on CAR 35 authorised person approval. The practical consequence is that operators choosing Requirement 2 must allow time for approval processes and may incur additional cost and administrative overhead.

Repaired spars and special approvals: Note 3 states that “Elevator spars repaired prior to the issue of Amendment 2 of this Directive shall be inspected at intervals not exceeding 100 hours time in service unless otherwise previously approved by the Authority.” If a spar was repaired prior to Amendment 2, the operator either must meet the 100‑hour inspection cadence or obtain prior Authority approval for an alternative. Obtaining such approval is a separate regulatory process and cannot be assumed.

Dependence on Piper MSB 998A and maintenance manuals: The AD mandates that Requirement 2 and Requirement 3 be accomplished “in accordance with the Instructions section of Piper MSB 998A” and the applicable maintenance manual, and that replaced parts be those listed in the MSB’s Material Required Table (Requirement 2 and Requirement 3). Failing to use the specified P/Ns or not following MSB instructions could render the work non‑compliant. Operators must ensure they have the correct revision of MSB 998A and applicable maintenance manual procedures available and used.

Immediate grounding risk where cracks are found: The AD requires replacement “before further flight” when cracks are found (Requirement 3 and Compliance). That creates a risk of immediate aircraft unavailability and associated commercial impact. Operators should plan for spares logistics and contingency scheduling.

Ice protection boot requirement: Requirement 4 mandates inspection of elevator ice protection boots and reinstallation or replacement before further flight if loose. This additional but potentially overlooked task must be included in inspection checklists.

Recordkeeping and auditability: Because the AD preserves earlier compliance times and links future replacements to the dates of certain inspections, maintenance logs need to be unambiguous about which inspections were carried out, under which requirement, and the hours at the time of inspection. Poor or incomplete records are a practical trap.

In short, the AD’s combination of historic compliance windows, alternative inspection regimes, approval requirements for access holes, conditional replacement timing, and reliance on external service information create several concrete operational “gotchas” that require careful scheduling, recordkeeping, approval management and spare part procurement.

This is a practical compliance checklist distilled from the AD’s Requirements and Compliance sections and the Notes. All work must be performed in accordance with the Instructions section of Piper MSB 998A when that Requirement is invoked, and replacements must be accomplished in accordance with the applicable maintenance manual and use the P/Ns listed in MSB 998A’s Material Required Table (Requirements 2 and 3).

1. Determine applicability

• Confirm whether the aircraft’s model and serial number fall within the AD’s Applicability list: PA‑31, PA‑31‑300, PA‑31‑325 (31‑2 through 31‑8312019); PA‑31‑350 (31‑5001 through 31‑8553002); PA‑31P‑350 (31P‑8414001 through 31P‑8414050). If the aircraft is listed, the AD applies.

2. Review maintenance records and hours

• Reconstruct the inspection history and component time in service for each elevator spar to determine which compliance timelines are already met or remain outstanding. Pay special attention to whether any Requirement 1 or Requirement 2 inspections have been previously completed and the dates/time in service at those inspections, because Compliance 3 replacement deadlines are measured from specific inspection events (Compliance).

3. Choose inspection pathway

• Elect Requirement 1 (visual and detail visual inspections) or Requirement 2 (install access holes per MSB 998A and perform boroscope inspection). The AD allows either path; the Background notes that repetitive visual inspection remains an option.

4. If electing Requirement 1 (visual/detail visual)

• Perform a visual inspection of upper and lower surfaces of the elevator spar from the outboard hinge to 9 inches (230 mm) inboard, inspecting for skin cracking, loose rivets and fretting (Requirement 1.a).

• Gain access as necessary and perform detail visual inspection of rear faces of left and right elevator spar webs at the inboard ends of outboard hinge doublers and forward faces at their outboard ends, paying attention to bend radii between rivets (Requirement 1.b and Figure 1).

• If cracks are found, replace the elevator spar assembly as required (Requirement 3, Compliance).

• Adhere to the timing: initial Requirement 1.a within 10 hours time in service after 12 October 1995 unless already done; Requirement 1.b before further flight if defects are found during 1.a, otherwise before 2,500 hours component time or within 100 hours after 20 October 1995, thereafter at intervals not exceeding 100 hours until replacement (Compliance 1).

5. If electing Requirement 2 (access holes and boroscope)

• Obtain or prepare an access‑hole scheme and secure approval from a CAR 35 authorised person, as Note 1 requires that installation be “in accordance with a scheme approved by a CAR 35 authorised person.”
• Install the access holes and perform boroscope inspections per the Instructions section of Piper MSB 998A (Requirement 2).
• Initial timing: upon accumulating 2,500 hours time in service on each elevator spar assembly, or within 100 hours after 31 December 1999, whichever occurs later; thereafter reinspect at intervals not to exceed 100 hours until replacement (Compliance 2).

6. If cracks are found at any time

• Replace the cracked elevator or elevator spar assembly with the improved‑design part numbers specified in the Material Required Table (page 4) of Piper MSB 998A. Perform replacements in accordance with the applicable maintenance manual (Requirement 3).
• If a crack is detected, replacement must be accomplished before further flight (Compliance 3).
• If only one spar is replaced because of a crack, continue to inspect the other spar every 100 hours until replacement at 1,000 hours after the initial inspection, or until a crack is found, whichever is first (Requirement 3 post‑replacement paragraph).

7. Replacement scheduling where no cracks are found

• Replacement deadlines for improved‑design parts: whichever occurs first , replacement before further flight if cracks are found; or within 1,000 hours time in service after the first Requirement 2 inspection performed after 31 December 1999; or within 1,000 hours time in service after the next Requirement 1 inspection after 24 February 2000 (Compliance 3). Calculate and log the appropriate 1,000‑hour deadlines depending on the inspection method used.

8. Ice protection boots

• Inspect elevator ice protection boots for looseness per the Instructions section of MSB 998A and reinstall or replace if loose before further flight (Requirement 4 and Compliance 4). Initial timing: within 100 hours after 31 December 1999 unless already done.

9. Repaired spars prior to Amendment 2

• If a spar was repaired prior to Amendment 2, inspect it at intervals not exceeding 100 hours unless otherwise approved by the Authority (Note 3). If seeking an alternative interval, obtain prior approval from CASA.

10. Documentation and maintenance release

• Record inspection findings, hours at inspection, any CAR 35 approvals for access holes, MSB 998A instructions followed, part numbers used for replacements, and maintenance manual references in the aircraft maintenance records.
• Do not release the aircraft to service if a required replacement is outstanding following a crack finding; replacement must be completed before further flight (Compliance).

11. Parts procurement and technical conformity

• Source the improved‑design elevator or spar assemblies using the “Replacement Elevator P/N” and “Replace Spar P/N” in MSB 998A’s Material Required Table (Requirement 3). Ensure parts and installation procedures conform to the maintenance manual.

12. Liaise with CASA where necessary

• If an operator wishes to vary inspection intervals or methods for situations covered by Note 3 or other provisions, seek prior approval from CASA (Authority), as the AD allows certain approvals by the Authority.

13. Keep MSB and manuals current

• Ensure access to Piper MSB 998A (Instructions section and Material Required Table) and the applicable maintenance manual, and comply strictly with the methods and P/Ns referenced because the AD makes compliance contingent on those documents.

By following the sequence above, operators will conform to the specific inspection, access‑hole, boroscope, replacement, boot inspection, approval and recordkeeping obligations that this AD prescribes. The central compliance tools are Piper MSB 998A and the applicable maintenance manual, plus any CAR 35 approvals required for access‑hole installations; replacement deadlines must be calculated from the specific inspection events described in the Compliance section.