AD/INST/56 Amdt 2 - Avidyne Corporation Primary Flight Displays

This Directive operates by singling out specific hardware (PFD part numbers and serial numbers) and imposing a mandatory identification-to-remediation pathway. The main technical concept is that certain PFDs were reported by the FAA to display incorrect attitude, altitude and airspeed information. To manage that risk, the Directive takes the following logical steps.

Identification. The first step is a record-based identification: Requirement 1 instructs operators to check maintenance records to determine installation of any affected PFD. Where records do not permit positive identification, Requirement 2 mandates a visual inspection for affected serial numbers. Note 3 clarifies that the registered operator or owner may perform Requirement 1 and make the compliance entry if they hold at least a private pilot’s licence.

Interim operating limitation. Where an affected unit is identified the Directive imposes operational limitations by way of insertion of the Appendix language into the AFM/POH/AFMS Limitations section, or if no AFM/POH/AFMS exists, by recording the Appendix in maintenance records and fabricating a placard with prescribed wording and a minimum character height of 3 mm, mounted within the pilot’s clear view. The Appendix is operational and procedural; it requires preflight crosschecks against known airfield elevation and between primary and backup instruments, prescribes airspeed checks on the ground and during takeoff, requires maintenance of current altimeter settings, and prohibits IFR or other flight in conditions where visual horizon reference cannot be maintained if the pilot suspects attitude, airspeed or altitude indications are unreliable. The Appendix further requires that aircraft be equipped with operating backup instruments that are readily visible.

Verification and terminating action. The Directive provides a terminating action to remove the imposed limitations where the PFD has been factory modified (labelled “Deviation 08-19A” or “MOD 52” on the exterior near the TSO label in accordance with SB Section 3.2) or has passed the air data system performance verification test identified in Section 3.3 of SB 601-00006-096 Revision 1. If the unit fails the test, Requirement 3.d requires removal and replacement with a conforming unit before the limitations can be removed.

Installation prohibition. Requirement 4 imposes a forward-looking ban on installation of affected PFDs as either initial fitment or replacement, unless they have passed the verification test or bear the factory modification marking. Notes clarify that FAA-approved alternate methods of compliance for the corresponding FAA AD are acceptable for compliance with this Directive, and that later FAA-approved revisions of SB 601-00006-096 are acceptable as AMOCs.

Timescales and trigger. Compliance times are short: initial checks and application of interim limitations within five days, tests and removals within 15 days, and the installation ban is immediate from the effective date. The Background links the Directive to FAA field reports of incorrect readings, and Amendment 2 expressly introduces the terminating action to the earlier operating limitations.

The Directive names a defined group of aircraft equipment and, through that equipment, a particular set of stakeholders. At the equipment level the directive affects Avidyne Primary Flight Displays having part numbers 700-00006-000, 700-00006-001, 700-00006-002, 700-00006-003 and 700-00006-100 with serial numbers listed in SB 601-00006-096 Revision 1. The Applicability text states that these PFDs are known to be installed on a non-exhaustive list of aeroplane models, specifically including Adam Aircraft Model A500; Cessna Model 441 where a STEC Alliant FAA STC SA09547AC-D is incorporated; Cessna LC42-550FG and LC41-550FG; Cirrus SR20 and SR22; Diamond DA 40; Hawker Beechcraft Model E90 and certain 200 series models where STEC Alliant STCs are incorporated; and a range of Piper models including PA-28, PA-32, PA-34, PA-44 and PA-46 variants. That list identifies the primary operator cohort: private owners, flight training organisations, charter operations and maintenance organisations operating those airframes where the identified Avidyne PFDs may be installed.

Registered operators and owners are the operational actors tasked with carrying out the initial logbook and visual inspection checks, and where applicable, placing the Appendix limitations into AFM/POH/AFMS or maintenance records and fabricating the placard. Note 3 and Note 5 explicitly allow the registered operator or owner to perform certain compliance activities (logbook checks, insertion of limitations, fabrication and installation of the placard) provided they hold at least a private pilot’s licence and enter compliance in the aircraft records. That gives small owner-operators and pilots the ability to self-certify compliance for those specific steps rather than requiring a licensed maintenance organisation for every action.

Maintenance organisations and licenced engineers are affected where the PFD needs the air data system performance verification test from Section 3.3 of the Service Bulletin, or where a failed test requires removal and installation of a replacement unit. The Directive refers to SB procedures for labelling verification and testing (Section 3.2 and 3.3), which are laid down by the manufacturer and referenced by the Directive.

Avidyne as the manufacturer may be indirectly affected: the directive’s terminating action relies on factory modification markings (“Deviation 08-19A” or “MOD 52”) and on the Service Bulletin test procedures. Suppliers and parts distributors are affected by the installation prohibition in Requirement 4, which constrains the pool of PFDs that may lawfully be fitted unless modified or proven by test.

Finally, regulatory actors include CASA and its delegates, with the Directive issued by CASA and signed by James Coyne as delegate. The directive references FAA AD 2009-05-05 Amdt 39-15829 and accepts FAA AMOCs; this creates a cross-jurisdictional interaction that affects manufacturers, maintenance organisations and operators who may rely on FAA-approved AMOCs for compliance.

The Directive creates specific duties with prescribed methods and timeframes, and it creates certain operational entitlements or pathways for relief.

Primary duties. The Directive’s principal duties are set out as Requirements 1 to 4.

• Requirement 1: Conduct a logbook check of aeroplane maintenance records to determine whether any affected PFD (identified by part number and serial numbers in SB 601-00006-096 Revision 1) is installed. If records positively identify that the installed PFD is not an affected serial number, no further action is required other than the ongoing installation restriction in Requirement 4. This action must be completed within five days of the Amendment becoming effective.

• Requirement 2: If records do not permit positive identification, visually inspect the PFD to determine whether the serial number is affected. If the visual check shows the installed PFD is not affected, no further action is required other than Requirement 4. This also must be completed within five days of the Amendment becoming effective.

• Requirement 3: If an affected serial-number PFD is installed, the operator must incorporate the Appendix’s operational limitations by inserting the Appendix language into the aircraft’s AFM/POH/AFMS Limitations section, or if those documents are not available, by inserting the Appendix into the maintenance records and fabricating and installing a cockpit placard with specified wording and minimum 3 mm letter height in the pilot’s clear view. This interim limitation must be in place within five days.

  Requirement 3 then requires inspection for the factory modification marking (“Deviation 08-19A”) or “MOD 52” near the TSO label in accordance with SB Section 3.2. If that marking is present, the limitation is removed. If not present, the owner must carry out the air data system performance verification test in Section 3.3 of the Service Bulletin. If the unit passes, the temporary limitations are removed. If the unit fails, Requirement 3.d requires removal and installation of a compliant unit.

• Requirement 4: PFDs with affected serial numbers may not be installed either as initial fitment or as replacement parts unless they have passed the verification test or have the factory modification label. This prohibition applies after the effective date.

Specified timelines apply: Requirements 1, 2 and 3.a within five days; Requirements 3.b, 3.c and 3.d within 15 days; Requirement 4 from the effective date.

Permitted actions and rights. The Directive contains mechanisms that operate as rights or relief pathways for affected parties.

• Terminating action: If a PFD bears the factory modification marking or passes the SB test, the previously imposed AFM/POH/AFMS limitations or placard/maintenance-record limitations are to be removed. That creates a clear remediation pathway for operators whose units can be modified or tested.

• Use of FAA AMOCs: Note 6 and Note 7 allow compliance by means of alternate methods of compliance (AMOC) approved by the FAA for the corresponding FAA AD, and later FAA-approved revisions of the Service Bulletin are acceptable. That provides a cross-acceptance route which operators and manufacturers can rely on, potentially reducing duplicative approvals.

• Self-performance of certain tasks: Notes 3 and 5 permit the registered operator/owner to perform the logbook check, install limitations into AFM/POH/AFMS or maintenance records, and fabricate and fit the placard, provided the owner holds at least a private pilot’s licence and records the action in the aircraft records. That reduces the immediate maintenance-provider burden for those specific compliance tasks.

Statement of safety rationale. The Background sets out the Directive’s stated safety objective: it resulted from FAA field reports of incorrect altitude and airspeed readings and was issued to prevent PFD display errors leading to airspeed/altitude mismanagement, spatial disorientation, loss of control, inadequate traffic separation or controlled flight into terrain.

No monetary penalties specified. The Directive itself does not specify fines, civil penalties or criminal sanctions. The document places obligations on the operator and owner to carry out actions within tight timeframes but does not state enforcement mechanisms or penalties in its text. Compliance is required from the effective date, and the directive is signed by a CASA delegate, indicating regulatory provenance.

The text of AD/INST/56 Amdt 2 does not set out express penalties, infringement notices or enforcement sanctions. The Directive prescribes mandatory compliance actions and precise timeframes, and it takes formal effect on 3 April 2009, but it contains no clause detailing the consequences of non-compliance within the instrument itself.

Because the Directive is issued by the Civil Aviation Safety Authority, it sits in the regulatory compliance ecosystem where a failure to comply with a CASA directive may be dealt with under broader aviation safety legislation or regulatory enforcement mechanisms outside the Directive’s text. The Directive records the issuance, the effective date and the CASA delegate’s signature, but it does not describe administrative, civil or criminal penalties, or specify processes for revocation or suspension of certificates. The instrument does, however, reference FAA AD 2009-05-05 and cross-acceptance of FAA AMOCs, which places compliance in a framework of mutual recognition with FAA airworthiness directives, but again does not itself specify sanctioning measures.

Practical enforcement implications for operators and maintenance organisations flow from the Directive’s mandatory operational consequences. For example, Requirement 4’s installation prohibition is an ongoing constraint on maintenance and parts procurement unless the unit has passed the verification test or bears the factory modification marking. Non-compliance in practice could create regulatory exposure when subject to an audit, airworthiness inspection or incident investigation, but those downstream enforcement processes and their legal consequences are not described in the Directive text.

The Directive explicitly allows the registered operator/owner to perform certain compliance actions and make entries in aircraft records if they hold at least a private pilot’s licence. That delegation of compliance tasks implies that CASA intends operators to be able to demonstrate compliance through documentary entries, AFM/POH/AFMS inserts and visible placards. Absent from the Directive are any procedural instructions about how CASA will verify compliance, audit schedules, or the remedial administrative steps that CASA would take in the event of non-compliance. The document therefore prescribes duties but leaves enforcement mechanisms to the general regulatory framework and CASA operational practice.

The Directive explicitly references the FAA regulatory framework and accepts certain FAA processes. Note 6 states that alternate methods of compliance approved by the FAA for FAA AD 2008-06-28 R1 are acceptable for compliance with this Amendment. Note 7 states that later revisions of SB 601-00006-096 approved by the FAA as an AMOC to FAA AD 2009-05-05 are acceptable for compliance with the equivalent Requirements of this Amendment. Note 8 specifically refers to FAA AD 2009-05-05 Amdt 39-15829. Those provisions create a direct interaction between CASA’s directive and FAA airworthiness directives and AMOC processes.

Practically, that means an FAA-approved AMOC or FAA-approved Service Bulletin revision can be relied on by Australian operators to satisfy the Directive’s requirements. The Directive therefore cross-recognises FAA airworthiness determinations and allows the manufacturer or FAA to define acceptable testing, modification or corrective procedures where those have been approved by the FAA. The interaction reduces duplication for operators and manufacturers who are already dealing with FAA compliance, and it aligns the CASA requirement with FAA outcomes.

The Directive also intersects with aircraft documentation and airworthiness recordkeeping regimes. Requirement 1 and Note 3 rely on aircraft maintenance records and the registered operator’s capacity to make entries. Requirement 3 requires insertion into the AFM/POH/AFMS or maintenance records, or fabrication and fitting of a specific placard. These obligations interact with statutory requirements on maintenance recordkeeping and AFM content; operators must ensure their AFM/POH/AFMS or maintenance records remain compliant with the broader airworthiness and operations rules while incorporating the Appendix material.

A further interaction arises with supplemental type certificates and major modifications. The Applicability expressly identifies multiple STC-incorporated installations (for example, STEC Alliant STCs) and lists affected airframes. That implicates the relationship between STC holders, installation STC terms and maintenance obligations for modified aircraft. Where an STC incorporates an affected PFD, the operator must follow the Directive’s pathway irrespective of the STC.

Finally, the Directive’s Requirement 4 affects parts supply and installation. It forbids installation of affected serial-number PFDs unless they have passed the prescribed test or carry the factory modification mark. That restriction interfaces with procurement, importation, parts traceability and continued airworthiness obligations under broader aviation law. The Directive does not itself regulate import controls or commerce, but it places an operational constraint that will have legal effects in those domains.

The document contains its own amendment history notes. The original issue of AD/INST/56 became effective 10 April 2008, as recorded in the Background. An Amendment 1 corrected a typographical error in the FAA AD number; the Background explicitly records that Amendment 1 was issued to correct that typographical error. AD/INST/56 Amdt 2, the instrument provided here, became effective on 3 April 2009 and introduces a terminating action to the operating limitations introduced by the earlier versions of the Directive.

The Amendment 2 text modifies the operational approach of the earlier Directive by adding a terminating action pathway. Specifically, whereas the initial Directive required the incorporation of operating limitations where an affected serial-number PFD was found, Amendment 2 allows those limitations to be removed if the PFD either bears the factory modification marking (“Deviation 08-19A” or “MOD 52”), or if it passes the air data system performance verification test set out in the Service Bulletin (Section 3.3 of SB 601-00006-096 Revision 1). Amendment 2 therefore turns the earlier, open-ended operational limitation into a temporary limitation that can be terminated on the basis of modification or testing.

Notes 6 and 7 in the Amendment clarify compliance pathways with FAA approvals. Note 6 states that FAA-approved AMOCs for FAA AD 2008-06-28 R1 are acceptable for compliance with this Amendment. Note 7 permits later revisions of SB 601-00006-096 that are approved by the FAA as AMOCs to FAA AD 2009-05-05 to be considered acceptable. Note 8 refers explicitly to FAA AD 2009-05-05 Amdt 39-15829, confirming that CASA has aligned the Amendment with the FAA airworthiness directive regime for the same underlying safety concern.

The Background to the Amendment recalls the sequence: initial issuance in April 2008, Amendment 1 to correct the FAA AD reference, and Amendment 2 to introduce terminating action and to align with the FAA AD and associated SB revisions. The document therefore contains the complete amendment history within its text: original effective date, a correction Amendment, and the current Amendment 2 effective 3 April 2009.

The Directive itself contains no litigation history, case references or recorded disputes. The text names no judicial decisions, administrative appeals or enforcement proceedings. It refers to FAA ADs and Service Bulletin outcomes but does not record judicial review or litigation arising from AD/INST/56 or its amendments.

Practical inference from the absence of recorded litigation in the Directive is limited by the document’s scope. The Directive is an administrative regulatory instrument setting mandatory compliance measures; enforcement action, appeals against enforcement, or judicial reviews would ordinarily occur under the broader statutory and administrative law framework. None of those downstream processes, if they exist, are documented in the Directive text.

The Directive does make concrete procedural allowances that could be the subject of dispute in future administrative or judicial proceedings, for example the acceptability of FAA AMOCs and the permissibility for registered operators to make compliance entries provided they hold a private pilot licence. Disputes could arise in practice about whether a particular AMOC is properly applicable to a given installation, whether a serial number has been correctly identified, whether the air data system performance verification test was correctly conducted in accordance with SB Section 3.3, or whether the factory modification markings are authentic and correctly located in accordance with SB Section 3.2. The Directive provides the technical criteria for those issues, but it contains no record of litigation testing those criteria.

Where disputes arise they would be resolved under CASA’s administrative procedures and, if escalated, by the courts or tribunals with jurisdiction over aviation administrative decisions. The Directive does not, however, supply any record of such proceedings and therefore offers no litigation precedent to guide interpretation beyond the Directive’s plain text and the referenced Service Bulletin and FAA AD materials.

The Directive contains a number of practical traps and detailed requirements that can give rise to inadvertent non-compliance if overlooked. These are specific and grounded in the Directive’s text.

Serial-number list is the defining criterion. Applicability depends on serial numbers listed in SB 601-00006-096 Revision 1. Note 1 states that the serial numbers listed in that Revision 1 are identical to those listed in AD/INST/56 and AD/INST/56 Amdt 1 except that PFDs subsequently serviced under an FAA-approved AMOC have been omitted. That means an affected unit might be excluded from the serial-number list because of an FAA-approved AMOC. Operators must ensure they refer to the exact revision of SB and to AMOC records, because an apparently affected serial number could in practice be compliant if an FAA AMOC applies.

Records versus physical inspection. Requirement 1 allows reliance on maintenance records if they positively identify that the installed PFD is not an affected serial number. However the Directive contemplates the common situation where records are incomplete or ambiguous and then requires visually inspecting the PFD in Requirement 2. Operators should be careful with identification: the PFD serial number location and the requirement to inspect for factory markings (“Deviation 08-19A” or “MOD 52”) near the TSO label per SB Section 3.2 are precise. Misreading or failing to locate the correct label could lead to unnecessary further actions or, conversely, missed non-compliance.

Who can sign. Note 3 and Note 5 allow the registered operator/owner to carry out the Requirement 1 determination and to insert limitations into AFM/POH/AFMS or maintenance records and fabricate the placard, provided they hold at least a private pilot’s licence and make an entry in the aircraft records. The gotcha is that an owner without a private pilot’s licence cannot perform those self-certification tasks; such an owner would need a maintenance organisation or another appropriately licensed person to make the entry and effect the insertions. Similarly, the owner must ensure the record entry is properly made, as it is the documentary proof of compliance.

Placard and AFM insertion specifics. For aircraft without AFM/POH/AFMS the Directive requires both inserting the Appendix into the aircraft maintenance records and fabricating a placard with a specified text and minimum letter size of 3 mm. Failure to install the placard or to record the Appendix properly creates a gap in compliance that may be revealed at inspection. The required placard text is not free-form; Requirement 3.a.ii(B) gives a precise wording that must be used.

Timing pressure. The five-day and 15-day deadlines are short. Requirements 1, 2 and 3.a must be done within five days of the effective date, with tests and remedial actions required within 15 days. Operators with multiple aircraft or with airframes away from main bases might find logistics and maintenance scheduling challenging. Requirement 4’s installation prohibition is effective immediately after the Amendment’s date; any PFD procurement or replacement after that date must ensure the unit has either been modified or tested.

Verification test protocol. The Directive requires the air data system performance verification test described in SB Section 3.3 where the factory modification marking is not present. That test must be performed correctly and documented. Operators should ensure the maintenance organisation conducting the test follows SB Section 3.3 exactly, otherwise a marginal or improperly recorded test could be challenged. The Directive does not itself specify who must perform the test, but the complexity of the test could make an appropriately authorised maintenance organisation the practical choice.

Removal and replacement cost. Requirement 3.d(i) requires removal and installation of a PFD that has passed the verification test, has been factory modified, or is not one of the affected serial-number PFDs. That creates a direct cost implication where a unit fails the test. Replacement parts, downtime and labour may be material for some operators. There is no funding mechanism or grace period described in the Directive. The operator must therefore budget for potential replacement or factory modification.

Parts market friction. Requirement 4 effectively constrains the pool of available replacement PFDs by prohibiting installation of affected serial-number units unless they pass the test or have the factory modification mark. In a thin domestic market for those parts, operators may face difficulty sourcing compliant replacement units rapidly.

Cross-jurisdictional AMOC dependence. The Directive’s acceptability of FAA AMOCs is a double-edged sword. It allows reliance on FAA approvals, but operators must ensure that the FAA AMOC precisely covers their particular serial-number unit and installation; otherwise the serial number may remain covered by the Directive. Misreading AMOC applicability may lead to inadvertent non-compliance.

Appendix operational prohibitions. The Appendix includes explicit operational prohibitions, including that flight under IFR or in conditions where horizon reference is unreliable must not be initiated or continued if the pilot has reason to suspect attitude, airspeed or altitude sources are unreliable, and that aircraft not equipped with operating backup attitude, altimeter and airspeed instruments readily visible to the pilot are prohibited from operation. The practical risk is that an operator who removes limitations prematurely or fails to ensure proper backup instruments may be operating in breach of the Appendix’s operational instructions.

Compliance requires a combination of documentary checks, physical inspection, AFM/POH/AFMS amendment or maintenance-record insertion, placarding where necessary, testing in accordance with the Service Bulletin, and possible removal and replacement. Below is a procedural checklist tied to the Directive’s Requirements and compliance times.

1. Identify applicability and effective date.

   • Note the Directive is AD/INST/56 Amdt 2 effective 3 April 2009. Confirm whether any aircraft under your control have Avidyne PFDs with part numbers 700-00006-000, 700-00006-001, 700-00006-002, 700-00006-003 or 700-00006-100.

2. Conduct the logbook check (Requirement 1, within five days).

   • Check maintenance records to see if an affected PFD serial number listed in SB 601-00006-096 Revision 1 is specified for each aircraft. If records positively show the installed PFD is not in the affected serial-number list, record compliance and note Requirement 4 continues to apply.
   • If you are the registered operator/owner and hold at least a private pilot’s licence, you may perform this check and make the compliance entry in the aircraft records, per Note 3.

3. If records are inconclusive, visually inspect the unit (Requirement 2, within five days).

   • Locate the PFD and read the serial number. If the serial number is not an affected number as per Revision 1 of the Service Bulletin, record the result and no further action is required beyond the continuing installation restriction in Requirement 4.
   • If the serial number is an affected serial number, proceed to Requirement 3.

4. Implement interim operational limitations immediately where an affected PFD is installed (Requirement 3.a, within five days).

   • For aeroplanes with an AFM/POH/AFMS, insert the Appendix language into the Limitations section. This may be accomplished by inserting a copy of the Appendix into the AFM/POH/AFMS, as Note 4 states.
   • For aeroplanes without AFM/POH/AFMS, insert the Appendix into the aircraft maintenance records and fabricate a placard with the prescribed wording in Requirement 3.a.ii(B), using letters at least 3 mm high, mounted on the instrument panel within the pilot’s clear view.
   • If you are the registered operator/owner and hold at least a private pilot’s licence, you may perform the Appendix insertion and placard fabrication and must make an entry in the aircraft records recording compliance, per Note 5.

5. Inspect for factory modification marking (Requirement 3.b, within 15 days).

   • Inspect the exterior of the PFD near the TSO label for a label marked “Deviation 08-19A” or a “MOD 52” marking, in accordance with Section 3.2 of SB 601-00006-096 Revision 1.
   • If the factory modification marking is present, remove the interim limitations and record the action in the maintenance records. No further action is required other than compliance with Requirement 4.
   • If the factory marking is not present, proceed to the verification test.

6. Conduct the air data system performance verification test (Requirement 3.b.(ii), Section 3.3 of the SB, within 15 days).

   • Arrange for the test to be performed according to Section 3.3 of SB 601-00006-096 Revision 1. Ensure the testing organisation documents the test results and that the documentation is retained in the maintenance records.
   • If the unit passes the test, remove the interim limitations and record the action. No further action is required other than the ongoing installation restriction per Requirement 4.
   • If the unit fails the test, proceed to removal and replacement.

7. Removal and replacement if the PFD fails the test (Requirement 3.d(i) and 3.d(ii), within 15 days).

   • Remove the failing PFD and install a PFD that either has passed the verification test, bears the factory modification mark, or is not one of the affected serial-number PFDs.
   • After replacement, remove the interim limitations and record the actions in the maintenance records.

8. Respect installation prohibition going forward (Requirement 4).

   • Do not install, either as initial fitment or as a replacement part, any PFD with an affected serial number unless it has passed the SB Section 3.3 verification test or bears a factory modification label (“Deviation 08-19A” or “MOD 52”).
   • Ensure procurement, inventory and parts-sourcing processes are adjusted to prevent use of non-compliant affected units.

9. Use FAA AMOCs where applicable (Notes 6 and 7).

   • If you have an FAA-approved AMOC that covers your unit or installation, document that AMOC and rely on it for compliance where specified. Confirm that the AMOC explicitly covers the serial numbers and installation configuration involved.

10. Documentation and record-keeping.

• Record all actions in the aircraft maintenance records and AFM/POH/AFMS as required. If you performed actions permitted under Note 3 or Note 5 as the registered operator with at least a private pilot licence, ensure you make the required entry in the aircraft records documenting compliance.
• Retain test reports and any Service Bulletin compliance documentation. Ensure placard installation is visible and that the placard wording matches the Directive’s requirement.

11. Pilot briefings and operational procedures.

• Ensure flight crews are briefed about the Appendix’s operational requirements. The Appendix requires preflight checks of primary and backup altimeters against known airfield elevation, verification of airspeed indications at startup and prior to takeoff, cross-checks at changes of altimeter setting and prior to IMC, and prohibition of IFR or certain night or night-over-water flights if instrument reliability is suspect. Ensure these procedures are integrated into SOPs.

12. Maintenance scheduling.

• Anticipate potential replacement parts and maintenance downtime if units fail the verification test. Ensure maintenance providers understand the SB test procedures and the requirement that modifications or tests produce documentation allowing removal of the interim limitations.

Following these steps, timed to the Directive’s specified periods, will place an operator in documentary and practical compliance with AD/INST/56 Amdt 2. Keep records of all compliance steps, as the Directive relies on such records both for initial identification and for removal of imposed limitations.