AD/SF340/108 Amdt 2 - Hydraulic System Accumulators

Applicability and scope: The AD applies to SAAB SF340A and SF340B aeroplanes fitted with hydraulic accumulators P/N 08 8423 001 1 or P/N 08 8423 030 1, except for accumulators carrying serial numbers listed in SAAB Service Bulletin (SB) 340-29-023 (dated 10 June 2008) or its revision 1 (dated 3 April 2009). The AD text uses the SB as the determinative document for serial-number exemptions and for the procedural steps that constitute compliance.

Mandatory replacement and acceptable compliance methods: Requirement 1 directs replacement of the listed accumulators "with a new or modified accumulator in accordance with SAAB SB 340-29-023 or later approved revision." The AD also records that replacement carried out per SAAB SB-340-29-024 Revision 01 is an acceptable alternative method to comply with Requirement 1. Thus the SB(s) contain the actionable technical instructions that implement the AD’s mechanical objective.

Installation prohibition and carve-out: Requirement 2 prevents installation, after a specified date, of accumulators of the two P/Ns on any aircraft, with the explicit exception of accumulators whose serial numbers are listed in the SAAB SB. The carve-out means some units of the same P/N may remain serviceable and reinstallable provided they appear on the SB serial-number list.

Compliance timing structure: The AD sets two concrete timing regimes tied to the accumulator manufacturing dates. For manufacture dates up to and including June 2000, a fixed 24-month window from the original AD effective date (25 September 2008) is given. For manufacture dates July 2000 and later, the later of two deadlines applies: within 10 years from manufacturing date, or within 24 months after 25 September 2008. Requirement 2’s prohibition on installation has a discrete effective date, after which installations of the old P/Ns are disallowed except for listed serial numbers.

Safety rationale and technical correction: The safety claim recorded in the AD is that corrosion and other failure modes have led to end parts departing from the pressure vessel, creating the risk of hydraulic system loss (affecting landing gear, flaps, brakes) and the possibility of debris penetrating the fuselage. The AD records that a modified accumulator has been developed; the modification is described functionally as sealing between the barrel and the screw cap and between the screw cap and the end cap. The Amendment 2’s mechanical effect is limited to correcting a compliance date clerical error; the AD states that the amendment "corrects the compliance date from 15 September 2008 to 25 September 2008 with no change to the requirements."

Normative references: The AD incorporates and makes mandatory the technical instructions in SAAB SB 340-29-023 and the acceptable alternative SB-340-29-024 Rev 01, and it cross-references EASA AD 2008-0146R1 (16 April 2009). The AD therefore operates by directing compliance to externally authored technical documents that have been approved or referenced by the issuing authority.

Authority and provenance: The AD is signed by James Coyne, Delegate of the Civil Aviation Safety Authority (CASA), dated 15 July 2009, and the Amendment becomes effective on 27 August 2009. The document structure reflects an initial AD issued with an effective date of 25 September 2008, which the Amendment corrects.

Aircraft operators: The primary direct addressees are operators of SAAB SF340A and SF340B aircraft on which hydraulic accumulators P/N 08 8423 001 1 or P/N 08 8423 030 1 are installed. Each operator must determine whether any of their aircraft have the affected part numbers and identify the serial numbers and manufacturing dates for each accumulator to determine applicable compliance timing and whether the part is an exception listed in SAAB SB 340-29-023 or its approved revisions.

Maintenance organisations: Licensed maintenance organisations and engineers performing maintenance on SF340 aircraft are affected because the AD requires replacement work to be done "in accordance with SAAB SB 340-29-023 or later approved revision" or via the acceptable alternative SB-340-29-024 Revision 01. These organisations will need to possess the referenced SBs, follow their instructions, and certify the work in the aircraft maintenance records as required by their regulatory obligations (note the AD text itself does not set out maintenance certification procedures; those remain in the wider regulatory framework).

Parts suppliers and stockholders: Suppliers, parts distributors and spares houses that stock or sell accumulators need to check inventories against the P/Ns and serial-number lists. The AD’s installation prohibition after 15 August 2010 restricts the circumstances in which those P/Ns can be fitted, thereby affecting logistics, sales, and inventory management. The AD also creates demand for the modified accumulator specified in the SB.

Regulator and certification authority: The AD was issued by a CASA delegate, James Coyne, and it refers to an EASA AD. This affects the regulator’s oversight role in ensuring operators comply with the replacement and installation prohibition, and in handling approvals for "later approved revision" language used in the AD.

Flight crew and passengers: The background safety rationale positions flight crew, passengers and people on the ground as stakeholders because the AD cites the risk of hydraulic system degradation or total loss of control of landing gear, flap actuation and brakes, plus the risk of debris penetrating the fuselage outer skin and injuring persons nearby. While the crew and passengers are not party to compliance obligations, the AD’s measures are framed to reduce risks that affect them.

Manufacturers: SAAB AB SAAB Aerosystems is implicated, both as the supplier of the service bulletins that contain the technical fix, and as the designer/manufacturer of the modified accumulator. The AD relies on SAAB SB 340-29-023 and SB-340-29-024 Revision 01 as the technical route to compliance.

Operators’ insurers and lessors: Though not explicitly named in the AD, insurers and aircraft lessors that underwrite SF340 operations will be materially interested because the AD imposes mandatory modifications that affect airworthiness status. That interest flows from the AD’s status as a mandatory directive rather than from explicit text in the AD.

Jurisdictional cross-reference: The AD cites EASA AD 2008-0146R1, indicating regulatory attention beyond the national level and potential parallel obligations for operators subject to EASA jurisdiction. The AD itself is a CASA instrument as signed by the delegate.

Mandatory replacement duty: Operators must replace hydrau­lic accumulators P/N 08 8423 001 1 and P/N 08 8423 030 1 (except those serial numbers listed in SAAB SB 340-29-023 or later approved revision) "with a new or modified accumulator in accordance with SAAB SB 340-29-023 or later approved revision." This is the primary duty in Requirement 1. The AD explicitly states an alternative compliance method: "Replacement of a hydraulic accumulator having P/N 08 8423 001 1 or P/N 08 8423 030 1 in accordance with the instructions of SAAB SB-340-29-024 Revision 01 is an acceptable method to comply with the Requirement 1 of this AD."

Installation prohibition: Requirement 2 creates a duty to refrain from installing accumulators P/N 08 8423 001 1 or P/N 08 8423 030 1 on any aircraft after the stated date, except for units with serial numbers listed in SAAB SB 340-29-023 or later approved revision. The AD makes this an explicit prohibition and sets an effective date for that prohibition: "For Requirement 2 - After 15 August 2010."

Compliance timing obligations: The AD specifies who must act when. For affected accumulators with manufacturing date June 2000 or earlier, replacement is due "within 24 months after 25 September 2008." For those manufactured in July 2000 or later, replacement is due "within 10 years from the manufacturing date or within 24 months after 25 September 2008, whichever occurs later." These timing rules create graduated enforcement windows tied to manufacture dates.

Obligation to follow referenced technical material: The AD mandates following SAAB SB 340-29-023 (or later approved revisions) for replacement, and accepts SB-340-29-024 Rev 01 as an acceptable method for Requirement 1. Therefore operators are obliged to use the technical instructions in those SBs when performing the replacement. The AD’s language about "later approved revision" indicates operators must ensure they are working to an approved revision of the SB.

Right to rely on listed serial-number exceptions: The AD grants an exception for certain serial-numbered accumulators as listed in the SAAB SB. Accumulators that appear on that serial-number list are outside the replacement and installation prohibition requirements. The AD does not itself list those serial numbers; it delegates that factual determination to the service bulletin.

No explicit penalty specification in the AD text: The AD does not set out penalties, fines, or precise enforcement mechanisms within the text provided. It states the required actions, the compliance windows, and the prohibition. The AD does not specify remedies, prosecution, or penalty amounts in this text. Enforcement and penalties, if any, fall to the applicable regulatory framework and enforcement practices that operate alongside ADs; they are not expressed within the AD document as provided.

Delegation and authority statements: The AD is issued by a CASA delegate, indicating the instrument flows from the Australian civil aviation safety regulatory system. The declaration that the amendment "becomes effective on 27 August 2009" is a formal administrative action that sets the operative date for the amendment; the AD also references an original effective date of 25 September 2008 which governs the timing windows specified.

Rights to use acceptable alternative method: By stating that SB-340-29-024 Revision 01 is "an acceptable method to comply" with Requirement 1, the AD creates a right for operators to use that particular SB procedure as an alternative route to compliance. The AD does not list other approved alternatives; operators must confirm whether any "later approved revision" has been authorised.

The AD text as provided does not specify penalties, sanctions or enforcement procedures. It gives mandatory requirements (replacement and an installation prohibition), timing for compliance and references to SAAB service bulletins for the technical implementation, but does not state fines, suspensions, or infringement notices, nor does it state the regulatory enforcement mechanism to be used in the event of non-compliance. The AD is signed by a CASA delegate and dated; that signature demonstrates the instrument’s formal regulatory provenance but, by itself, does not in this text provide the enforcement detail.

Practically, the AD imposes obligations on operators and maintenance organisations to effect replacements and to avoid installing the specified part numbers after the named effective date for Requirement 2. Where the text is silent on penalties, implementation and compliance oversight typically rest with the issuing authority and its normal enforcement powers. The AD does, however, create clear compliance deadlines and technical instructions; in most regulatory ecosystems an AD constitutes an airworthiness requirement that must be complied with to retain the aircraft’s lawful airworthiness certification. The AD here sets specific compliance windows and an installation prohibition; the presence of those directives means that operators who do not conform to the AD are, at a minimum, outside the specified requirements.

The Amendment 2 content corrects a prior compliance date and states that the amendment "becomes effective on 27 August 2009"; that effective date establishes the formal point at which the corrected administrative record takes effect. The AD also cites EASA AD 2008-0146R1 dated 16 April 2009, which indicates related regulatory action in another jurisdiction. The AD itself does not describe cross-border enforcement, mutual recognition, or how non-compliance will be treated by other jurisdictions.

Because the AD defers technical detail and serial-number specifics to SAAB service bulletins, a regulator enforcing compliance would require access to those SBs and to maintenance records showing that the replacement work was performed "in accordance with SAAB SB 340-29-023 or later approved revision" or using the acceptable alternative. The AD’s silence on enforcement mechanisms in the provided text means that readers should not assume the presence or absence of particular penalties from the AD alone.

Reference to external regulatory instrument: The AD explicitly cross-references EASA AD 2008-0146R1 dated 16 April 2009. That reference indicates parallel or related regulatory action in the European Aviation Safety Agency framework. The AD therefore sits within a web of safety directives where actions taken by one authority are cognate with actions by another.

Incorporation of manufacturer service bulletins: The AD makes compliance conditional upon following SAAB Service Bulletin 340-29-023 "or later approved revision" and accepts SAAB SB-340-29-024 Revision 01 as an acceptable method to comply with Requirement 1. The AD therefore operates by making the content of those SBs mandatory for the affected operators. Those SBs are external technical documents issued by the aircraft manufacturer; their incorporation means that the AD’s operative requirements depend on the content and any "approved revisions" of those technical documents.

Interaction with airworthiness certification: The AD’s replacement and installation prohibition are airworthiness measures. While the AD itself does not restate the broader statutory powers or certification rules under which an airworthiness directive may be enforced, its issuance by a CASA delegate indicates it functions within the civil aviation regulatory framework for airworthiness. The AD’s directives will interact with maintenance certification, logbooks and any statutory obligations operators have to maintain the aircraft in an airworthy condition. The AD does not reproduce those broader maintenance and certification obligations in full.

Temporal interaction and amendment: The Amendment 2 document corrects a compliance date in the original AD and specifies its own effective date (27 August 2009). The AD also states that the original issue's effective date was 25 September 2008. These dates matter because the AD ties replacement deadlines to the original effective date and to manufacturing dates of the accumulators. Any other legal instruments or contracts that reference the original AD compliance schedule need to accommodate the corrected date.

Conditional reliance on "later approved revision": The AD’s phrase "or later approved revision" for the SAAB SB creates an interaction point with the regulatory approval process for revisions of service bulletins. That approval step is administered by the regulator; hence the AD defers to the regulator’s approval of subsequent SB revisions, integrating an approval mechanism implicit in the wider regulatory system.

Supply and procurement law interfaces: By restricting installation of certain P/Ns after a set date, the AD affects procurement decisions and aftermarket supply chains. While the AD does not directly regulate contracts, commercial agreements for parts supply and warranties will operate in the background; the AD therefore intersects with contractual and commercial law by changing which parts are permitted to be installed.

No explicit statement on criminal or civil enforcement in the AD text: The AD does not specify how it interacts with criminal or civil liability regimes. The presence of mandatory safety requirements normally has implications for insurers, tort liability, and contractual warranties, but those interactions are not spelled out in the AD itself.

Initial AD and effective date: The original AD had an effective date of 25 September 2008. The AD’s compliance timing for Requirement 1 is expressed relative to that original effective date. The text of Amendment 2 states that the amendment "corrects the compliance date from 15 September 2008 to 25 September 2008 with no change to the requirements." That indicates that a prior document or version contained a clerical error in the original stated compliance date which Amendment 2 corrects.

Amendment 2 specifics and effective date: This document is "AD/SF340/108 Amdt 2," titled "Hydraulic System Accumulators," and is dated 9/2009 in the header. The amendment becomes effective on 27 August 2009. The AD retains Requirement 1 and Requirement 2 from the original AD but corrects the incorrect compliance date. The AD explicitly notes "This Amendment becomes effective on 27 August 2009."

Service bulletin revisions: The AD’s applicability paragraph identifies SAAB Service Bulletin (SB) 340-29-023 dated 10 June 2008 and revision 1 dated 3 April 2009 as the documents that list serial number exceptions. The AD also references SAAB SB-340-29-024 Revision 01 as an acceptable method for complying with the replacement requirement. The AD language that allows "later approved revision" implies an expectation that the SBs may be revised and approved later, and that such approved revisions will be effective for compliance purposes.

Cross-reference to EASA amendment: The AD includes a note that "EASA AD 2008-0146R1 dated 16 April 2009 refers." This cross-reference indicates that EASA issued its own AD relating to the same unsafe condition, and that the Australian AD acknowledges that related instrument. The Amendment 2 corrects a compliance date but does not alter the substantive replacement or installation prohibition requirements.

Chronology of reported failures and AD evolution: The background states there were initially two reported cases of main hydraulic accumulator failure, one caused by corrosion, and that since the original issue of the AD another failure occurred in flight during final approach. The Amendment 2 records those safety incidents as the rationale behind the AD and then clarifies its administrative dates without changing substantive obligations.

Administrative signature and record: The document is signed "James Coyne, Delegate of the Civil Aviation Safety Authority" and dated 15 July 2009, which is the formal administrative record for the Amendment. The AD shows as header lines and repeated labels "AD/SF340/108 Amdt 2" and "Hydraulic System Accumulators" with the date formatting "9/2009" indicating the amendment number and month/year reference.

The provided AD text contains no litigation history. There are no references in the document to judicial proceedings, appeals, administrative reviews, or legal challenges to the AD or to SAAB service bulletins. The AD records the technical failures that prompted the directive, and it cross-references an EASA AD, but it does not record any litigation, contested cases, or court decisions arising from the AD or the incidents described.

Because the AD is silent on litigation, the document does not identify any instances where operators, manufacturers or other parties sought judicial remedy, nor does it describe outcomes of any disputes. The AD simply sets out mandatory technical measures, compliance timelines, and an installation prohibition tied to serial-number exceptions. Any litigation that may have arisen before or after the AD’s issuance is not documented in the material provided.

Users seeking litigation history should note that it is not present in the AD text. To uncover litigation, one would need to consult court records, administrative tribunal decisions, or regulatory enforcement records outside the scope of this AD document.

Serial-number exception dependence: The AD’s applicability exemptions rely entirely on the SAAB service bulletin (SB 340-29-023, dated 10 June 2008, and revision 1 dated 3 April 2009) for the list of serial numbers that are exempt from replacement and from the installation prohibition. The AD itself does not list those serial numbers. Operators must therefore obtain and consult the specified SAAB SB(s) to determine whether particular accumulators are exempt. The AD also allows "later approved revision," which means an updated SB might change the exemption list; operators need to confirm which revision is approved for compliance.

Two different replacement instruction sources: The AD makes SAAB SB 340-29-023 the operative instruction for replacement, but it also specifically records that replacement in accordance with SAAB SB-340-29-024 Revision 01 is an acceptable method to comply with Requirement 1. Both SBs are therefore relevant; maintenance planners must ensure they are using the correct SB and the correct revision that is "approved" under the AD.

Dual timing regimes tied to manufacture dates: The compliance deadlines differ depending on the accumulator manufacturing date. For units manufactured June 2000 or earlier, the replacement deadline is "within 24 months after 25 September 2008." For units manufactured from July 2000 onwards, the deadline is "within 10 years from the manufacturing date or within 24 months after 25 September 2008, whichever occurs later." Operators must have accurate manufacturing-date records for each accumulator to apply the correct deadline. Errors in manufacturing-date records could result in missed deadlines.

Amendment corrects compliance date but leaves substantive requirements unchanged: Amendment 2 corrects a clerical compliance-date error (from 15 September 2008 to 25 September 2008) and states explicitly that there is no change to the requirements. Those tracking compliance windows must use the corrected 25 September 2008 date when computing the 24-month period specified.

Installation prohibition effective date: Requirement 2 (the installation prohibition) becomes effective "After 15 August 2010." That means that until that date, installation of the listed P/Ns may be lawful subject to the AD’s applicability exceptions; after that date, the P/Ns cannot be installed except if the accumulator has a serial number listed in the SAAB SB. Maintenance planners and parts managers must ensure they do not inadvertently install prohibited P/Ns after the effective date.

Safety risk described includes in-flight failure: The AD notes that one of the reported failures "occurred in flight during final approach" though the aeroplane was able to land safely. The AD’s background highlights potential outcomes including "degradation or total loss of control of the landing gear, flap actuation and brakes" and possible debris penetration of the fuselage outer skin. This is not merely a ground-damage issue and affects in-flight critical systems; therefore operators should treat the AD with high priority.

Reliance on manufacturer SB “later approved revision”: Because the AD permits compliance by following the original SB or "later approved revision", there is potential for ambiguity unless operators confirm which SB revisions have been approved by the regulator. A compliant action must be tied to an SB revision that the authority recognises as approved for AD compliance.

No penalties stated in the AD text: The AD does not set out enforcement penalties or consequences for non-compliance within the document as provided. Parties should not assume the regulatory response or penalty structure from the AD text; enforcement will follow the broader regulatory regime and agency practices, not content in this AD.

Recordkeeping and proof of compliance not specified: The AD does not include detailed requirements on how compliance must be documented in maintenance records. Standard practice requires appropriate logbook entries and documentation, but operators cannot find prescribed record formats or certification language within this AD; they must rely on standard maintenance certification requirements and on the referenced SB instructions.

Cross-reference to EASA AD: The AD’s note that "EASA AD 2008-0146R1 dated 16 April 2009 refers" means operators with operations in jurisdictions subject to EASA should check the EASA AD for any differences or other requirements. Differences between the CASA AD and the EASA AD, if any, would need to be reconciled by operators with cross-border operations.

1. Identify affected aircraft and parts:

   • For each SAAB SF340A or SF340B in an operator’s fleet, inspect maintenance records and the physical accumulators to determine whether accumulators P/N 08 8423 001 1 or P/N 08 8423 030 1 are installed.
   • Determine the serial number and the manufacturing date for each such accumulator. The AD’s compliance deadlines and exemption status depend on those two data points.

2. Consult SAAB Service Bulletin 340-29-023 and its approved revisions:

   • Obtain SAAB SB 340-29-023 dated 10 June 2008 and revision 1 dated 3 April 2009.
   • Check the serial-number list in that SB. Any accumulators whose serial numbers appear on that list are exempt from replacement and are excepted from the installation prohibition.
   • Confirm whether a "later approved revision" of the SB has been issued and approved by the competent authority; if so, use the latest approved revision as permitted by the AD.

3. Apply the correct compliance timing:

   • For accumulators with manufacturing date June 2000 or earlier, ensure replacement occurs within 24 months after 25 September 2008 (that is the deadline stated in the AD).
   • For accumulators with manufacturing date July 2000 or later, ensure replacement occurs either within 10 years from the manufacturing date or within 24 months after 25 September 2008, whichever is later.
   • Track these deadlines carefully; use the corrected date (25 September 2008) as the baseline for the 24-month calculation, per Amendment 2.

4. Use the mandated replacement procedure:

   • The AD requires replacement "in accordance with SAAB SB 340-29-023 or later approved revision." Obtain and follow those instructions precisely for the physical replacement.
   • Alternatively, the AD accepts "SAAB SB-340-29-024 Revision 01" as an acceptable method to comply with Requirement 1. If using that SB, ensure the revision specified is the correct one and follow its instructions.

5. Address installation prohibition:

   • Do not install accumulators P/N 08 8423 001 1 or P/N 08 8423 030 1 on any aircraft after 15 August 2010, unless the accumulator’s serial number is listed in SAAB SB 340-29-023 (or a later approved revision). Ensure parts procurement and maintenance planning respect this prohibition.

6. Document and certify work:

   • Although the AD does not specify recordkeeping forms, maintain clear maintenance records that identify the removed accumulator P/N, serial number, manufacturing date, the service bulletin used for the replacement, date of replacement and details of the replacement part. Use standard maintenance certification processes to record compliance with the AD.
   • Retain SAAB SB copies and revision details used to perform the work, in case the regulator requests proof of compliance.

7. Coordinate parts procurement:

   • Order the modified accumulator specified in the SAAB SB to perform the replacement. Confirm the modified accumulator is the correct serviceable part described in the SB, including the sealing features (seal between barrel and screw cap and between screw cap and end cap) noted in the AD’s background.

8. Manage fleet scheduling and downtime:

   • Plan replacements to meet the AD timing windows and to minimise disruption. The AD imposes mandatory replacement, so schedule maintenance slots before the applicable deadlines. For units approaching the 24-month deadline or their 10-year manufacturing date, prioritise replacements.

9. Confirm regulatory approvals:

   • If relying on "later approved revision" language, confirm with the regulator which service bulletin revisions are approved for AD compliance. Do not assume that a newer SB revision is automatically approved for the AD; approval is the necessary step per the AD’s phrasing.

10. Consider cross-jurisdictional requirements:

    • If aircraft also operate in EASA jurisdictions or under other aviation authorities, consult EASA AD 2008-0146R1 (16 April 2009) and any local directives to ensure there are no additional or differing requirements. The AD itself notes the EASA AD reference.

11. Maintain safety awareness:

    • The AD’s background emphasises the risk of corrosion and catastrophic failure that can degrade landing gear, flaps, brakes and can produce fuselage-penetrating debris. Treat the AD as addressing an in-flight and on-ground safety hazard, and prioritise compliance accordingly.

12. Seek clarification if uncertain:

    • Where questions arise about which SB revision is "approved", or about serial-number status, contact the regulator or the SAAB technical representative. The AD defers to "later approved revision", which requires confirmation of approval status.

Who bears the cost and operational impact: Operators and maintenance organisations must execute and pay for the replacements, procure modified parts and schedule aircraft downtime. The AD does not provide cost-sharing or funding mechanisms; the financial and logistics burden falls on the entities responsible for maintaining the affected aircraft.

By following these steps, operators align their maintenance actions with the AD’s requirements: replace affected accumulators per the specified SAAB service bulletins within the defined deadlines, avoid prohibited installations after 15 August 2010 except for SB-listed serial-number units, and keep documentary evidence of compliance tied to the SB revision used.