AD/CESSNA 206/66 - Alternate Static Air Source Selector Valve Placard

The AD’s core technical concept is that a small identification placard attached to an alternate static air source selector valve may obstruct the valve port and thereby interfere with the static source used for instruments. The consequence is erroneous instrument indications: the AD explicitly links port obstruction to potential erroneous readings of the altimeter, airspeed and vertical speed indicators (Background). The AD thus treats the placard as a potential latent defect in the valve assembly which can compromise primary flight instruments.

The directive distinguishes between two operational statuses of aeroplanes , those equipped for flight under instrument flight rules (IFR) and those not so equipped , and imposes different compliance timing and temporary mitigations accordingly (Requirement 1-3 and Compliance column). For IFR-equipped aeroplanes where immediate inspection is impracticable it provides a risk-mitigation path by requiring installation of a conspicuous instrument-panel placard prohibiting IFR operation and use of the alternate static source (Requirement 2b). The temporary placard is mandated to use at least 1/8-inch letters and to be within the pilot’s clear view, a procedural control designed to reduce the probability of inadvertent IFR flight or inadvertent use of the alternate static source when the valve’s port may be obstructed.

The AD uses a capture rule that combines model identity (the detailed Table 1 list of Cessna 206-series variants) with production and parts-supply date ranges. It captures any aeroplane initially delivered between 1 January 1993 and 31 March 2008 unless the modification/rework mandated by an earlier AD (AD/CESSNA 206/65) has been done and remains in compliance (Applicability). It also captures any aeroplane that had P/N 2013142-18 installed as a replacement part at any time after 1 January 1993, unless that earlier AD’s modification/rework has been done. This mixed rule ties airframe delivery date, service history and parts replacement together to define applicability, reflecting the fact that the problematic valves were shipped during a defined period (Note 1).

Procedurally the AD refers to Cessna-issued service bulletins for the detailed inspection and corrective procedures (Requirement paragraph). That means the AD delegates the specifics of how to inspect and how to remove placards to the manufacturer’s service documents, which are incorporated by reference for technique and access considerations. The AD also sets a prophylactic installation rule: after 10 days from the effective date, replacement valve installations are constrained to P/N 2013142-18 units that have already been inspected and found free from obstruction (Requirement 5 and Compliance). That creates an immediate supply-side compliance requirement for maintenance organisations and parts suppliers.

Finally, the AD anchors its issuance in earlier FAA action. The Background records that AD/CESSNA 206/65 was issued in response to FAA AD 2008-10-02, and that the FAA later issued AD 2008-26-10 Amdt 39-15776 (referenced in Note 3). The AD therefore sits in a chain of airworthiness actions begun by the FAA, with CASA adopting equivalent remedial steps for Australian-registered aeroplanes and inventories.

The immediate and primary class of affected persons and entities are owners and operators of the specific Cessna 206-series aeroplanes listed in Table 1 of the AD. Table 1 enumerates numerous type variants across single- and multi-engine 206 family designations (examples: 206, 206H, P206C, T206H, TU206C, U206C, TP206A, TU206D and many others). The Applicability paragraph clarifies that the AD catches aeroplanes initially delivered between 1 January 1993 and 31 March 2008, unless the modification/rework required by AD/CESSNA 206/65 has been done and the aeroplane remains in compliance with that AD. It also catches aeroplanes that have had P/N 2013142-18 installed as a replacement part any time after 1 January 1993, subject to the same exception.

Maintenance organisations, licensed aircraft engineers, and base maintenance providers are directly affected because they must perform the prescribed inspections and remedial work in accordance with the AD and the referenced Cessna service bulletins. The AD makes the Cessna service bulletins the source of the detailed procedures ("The procedures required to accomplish this AD are detailed in Cessna... SB08-34-02 Rev 1;... CAB08-04 Rev 1;... SEB08-5;... MEB08-6, as applicable.").

Parts suppliers, especially those holding inventory of P/N 2013142-18 selector valves, are affected by Requirement 5 which prohibits installation of replacement P/N 2013142-18 valves after the specified date unless the valve has been inspected and its port is free from obstruction. Note 1 in the Applicability explicitly states that the affected part was shipped from Cessna Parts Distribution between 1 January 1993 and 31 March 2008, which identifies a period during which inventory and spares could have been distributed.

Pilots and operators who conduct IFR flights are particularly affected because the AD imposes a short 10-day compliance window for either inspection or immediate installation of a prohibitive placard for IFR aircraft (Compliance table: Requirement 2a within 10 days; Requirement 2b before further flight). If an IFR-equipped aeroplane elects to use the temporary placard option, its IFR capability is explicitly curtailed by the AD: the placard must state "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED", and must be installed within the pilot’s clear view.

Regulators and auditors within CASA and aerodrome/airworthiness inspectors are affected in that they will be the parties verifying compliance. The AD is issued by CASA (signature by James Coyne, Delegate) and becomes effective on 16 January 2009, which creates a date by which operators must comply or be unable to rely on compliance with Australian delegated airworthiness direction.

Finally, the AD affects safety managers, compliance officers and insurance underwriters who must track the AD’s action items. The Background emphasises the safety rationale: reports of valves with obstructed ports and consequent risk of erroneous instrument indications, which in turn can cause improper pilot reactions with potential for loss of control. That safety risk drives the compulsory nature of the inspections and the temporary operational limitations for IFR aeroplanes.

Duties imposed by the AD are explicit and prescriptive. They include:

• Inspect the alternate static air source selector valve to confirm that the part number identification placard does not obstruct the port (Requirements 1, 2a, 3). For non-IFR aeroplanes this inspection must occur within the next 100 hours TIS or within 4 months after the AD’s effective date, whichever occurs first; for IFR aeroplanes the inspection option (2a) is due within 10 days (Compliance).
• For IFR-equipped aeroplanes where immediate inspection cannot be accomplished, fabricate and install a temporary instrument-panel placard with the exact words "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED", using letters at least 1/8-inch high, and place it in the pilot’s clear view (Requirement 2b). The AD requires removal of such temporary placards after the valve inspection in Requirement 3 and before further flight.
• If inspection reveals that the part number placard obstructs the valve port, remove and discard that placard and ensure the port is open and unobstructed before further flight (Requirement 4).
• From the date specified in the Compliance table, when replacement valves are needed only install P/N 2013142-18 units that have been inspected and found free from port obstruction (Requirement 5 and Compliance).

The AD also directs the use of specific Cessna service bulletins for detailed procedures: SB08-34-02 Rev 1, CAB08-04 Rev 1, SEB08-5, and MEB08-6, as applicable (Requirement paragraph). Compliance therefore entails following the manufacturer’s procedural guidance as incorporated by the AD.

Rights under the instrument are procedural rather than compensatory. The AD affords aeroplane owners and maintainers the right to follow the specified inspection and remediative steps as the method of compliance. The AD provides a clear alternative for IFR-equipped aeroplanes , either conduct the inspection rapidly or adopt temporary prohibitive placards to mitigate immediate risk while scheduling inspection (Requirement 2a/2b). There is no express right in the AD to monetary compensation, deferment, or alternative corrective actions beyond those provided; the AD does not detail an application process for exemptions or extensions in the text provided.

The AD also conditions applicability by exception: if the aeroplane has already had the modification/rework required by AD/CESSNA 206/65 and remains in compliance with that prior AD, then the new AD does not apply (Applicability). That exception is a limited right attaching to aeroplanes already compliant with AD/CESSNA 206/65.

Operationally, the AD imposes immediate duties on IFR aircraft through a 10-day inspection window or pre-flight placarding, and imposes a requirement to remove temporary placards after the underlying valve inspection is completed before further flight (Requirement 3). Thus operators must schedule inspections and maintenance within specific regulatory time limits, and ensure that temporary operational limitations are visible to flight crews during the interim.

The AD sets a required standard for spares: replacement valves installed after the specified compliance date must have been inspected and found free from obstruction (Requirement 5). This changes procurement and parts-handling practice for maintenance organisations and suppliers.

Finally, the AD is effective as of 16 January 2009 (Compliance: "This Airworthiness Directive becomes effective on 16 January 2009"), which fixes the date from which the duties and timeframes apply.

The text of the AD itself does not set out monetary penalties, criminal sanctions, or a detailed enforcement procedure. It is an airworthiness directive issued by CASA and signed by a delegate (James Coyne), and in that sense it is an obligatory regulatory instrument with an effective date: 16 January 2009 (signature block and Compliance). The AD prescribes mandatory actions (inspections, placarding, removal of obstructing placards, and restricted installation of replacement parts) and specified compliance windows; non-compliance with such an AD typically affects the lawful continuance of aircraft operations because the AD addresses continuing airworthiness obligations and operational safety, but the AD text provided does not itself describe the enforcement mechanisms or penalties available to CASA in the event of non-compliance.

In practical terms, enforcement mechanisms typically available to an airworthiness regulator include regulatory audits, airworthiness certificate actions, maintenance release or logbook checks during surveillance, and grounding of airframes until compliance is demonstrated. The AD requires removal of temporary placards only after inspection is done and the valve is confirmed clear (Requirement 3), and requires that valves installed after a specified date must have been inspected (Requirement 5), both of which create documentary and physical checks that an inspector can verify. The AD’s prescription of referenced Cessna service bulletins for the detailed procedures provides an auditable method of compliance: inspectors can check that the appropriate SB was followed.

Because the AD does not set out specific penalties, the AD’s enforcement will be exercised through CASA’s broader regulatory and compliance powers rather than via an express penalty clause in the AD. The Background notes reports of unsafe conditions (port obstruction causing erroneous instrument indications) and explicitly links those to possible loss of control, giving the regulatory rationale for mandatory action.

The AD also references FAA actions (FAA AD 2008-26-10 Amdt 39-15776 and earlier FAA AD 2008-10-02), which can matter for cross-jurisdictional oversight where aircraft or parts are imported or maintained under overlapping jurisdictions. While the AD does not specify reciprocal enforcement mechanisms, the practical enforcement risk arises for operators who fail to perform the required inspections or removal; they would face enforcement under the general civil aviation regulatory regime when non-compliance is discovered, and such findings could affect the aircraft’s continued airworthiness approval and the operator’s regulatory standing.

In short, the AD is mandatory and prescriptive, but the instrument itself does not enumerate penalties in the text. Enforcement will be through CASA’s usual airworthiness and surveillance channels, using the AD’s clear compliance steps, timelines and referenced service bulletins as the standard against which compliance is judged.

The AD explicitly situates itself within other airworthiness actions and service material. It was issued in the context of earlier CASA and FAA actions: AD/CESSNA 206/65 (a prior CASA AD) was prompted by FAA AD 2008-10-02 (Background). The AD expressly notes that FAA AD 2008-26-10 Amdt 39-15776 dated 15 December 2008 refers (Note 3). In effect the AD is CASA’s parallel action in response to the same known unsafe condition identified by the FAA, and it cross-references both earlier CASA AD/CESSNA 206/65 and those FAA ADs as part of its regulatory genealogy.

The AD also incorporates by reference the manufacturer’s Cessna service bulletins (SB08-34-02 Rev 1; CAB08-04 Rev 1; SEB08-5; MEB08-6) for the detailed procedures. By doing so it creates a direct interaction between a regulatory instrument and non-legislative technical material issued by the manufacturer. In practice, compliance with the AD entails following those service bulletins’ steps, so the AD converts the manufacturer guidance into a regulatory requirement.

Beyond the direct references, the AD interfaces with the broader obligations of aircraft operators and maintenance organisations under the national civil aviation regulatory framework. While the AD text does not quote specific provisions of the Civil Aviation Regulations or the Civil Aviation Safety Regulations, it implicitly modifies continuing airworthiness obligations: operators of affected aeroplanes must perform inspections or adopt temporary operational limitations, and maintenance entities must ensure parts installed meet the AD’s inspection standard. That means the AD interacts functionally with any legal duties to maintain aircraft in an airworthy condition, to record maintenance in logbooks, and to have maintenance carried out by appropriately certificated personnel.

Parts supply and installation law also interact with the AD. Requirement 5 restricts the installation of P/N 2013142-18 valves to those that have been inspected and found unobstructed as of 10 days after the effective date. This interacts with procurement, stock control and logbook documentation processes: suppliers and maintainers must be able to demonstrate that installed parts have been inspected per the AD.

The AD does not address insurance law directly, but the safety risk and mandatory nature of the AD imply that failure to comply could affect positions in insurance claims or liability determinations after an incident. The AD’s Background links port obstruction to potential erroneous instrument readings and loss of control; if an operator failed to follow a mandatory AD and that failure contributed to an incident, that fact would likely be material in subsequent liability or insurance assessments, although such consequences are not detailed in the AD.

Finally, the AD’s reference to FAA ADs indicates transnational coordination in addressing the unsafe condition. For aircraft that operate internationally or that are maintained under multiple jurisdictions, there will be an interaction between CASA’s AD and the FAA’s ADs as to expectations for parts inspection and records. The AD itself acts as CASA’s declaratory instrument specifying the Australian regulatory response to the same technical problem identified overseas.

The text supplied records this instrument as AD/CESSNA 206/66, Alternate Static Air Source Selector Valve Placard, with an issue date signed 8 January 2009 and an effective date of 16 January 2009. The AD references earlier related instruments and subsequent FAA action, which forms the relevant amendment history as recorded in the AD itself.

Relevant items in the AD’s chain are:

• AD/CESSNA 206/65: an earlier CASA AD prompted by FAA AD 2008-10-02 (Background). The current AD explicitly excludes aeroplanes that have had the modification/rework required by AD/CESSNA 206/65 and remain in compliance with that AD from its applicability (Applicability). The presence of that exception records an immediate amendment relationship: AD/CESSNA 206/66 is narrower or complementary to the earlier AD for those aeroplanes already modified.
• FAA AD 2008-10-02: the FAA action that initially prompted AD/CESSNA 206/65 (Background).
• FAA AD 2008-26-10 Amdt 39-15776 dated 15 December 2008: the FAA action referred to in Note 3 of the AD.
• Manufacturer service bulletins dated October 2008 (SB08-34-02 Rev 1, CAB08-04 Rev 1, SEB08-5, MEB08-6) are the procedural documents referenced by the AD and thereby form part of the technical amendment history by being the required method of compliance.

The AD also records that P/N 2013142-18 replaced earlier part numbers 2013142-9, -13 and -17 (Note 2). That replacement history is relevant to amendment and applicability: it indicates that earlier part numbers were superseded by the P/N at issue, and explains why parts and spares supply across the 1993-2008 timeframe could include the affected valve.

No later amendments, revocations, or superseding CASA ADs are recorded in the supplied text. The supplied instrument appears to be a stand-alone directive with an effective date and explicit compliance times. If amendment or revocation occurred after the effective date, that material is not present in the text supplied; the AD itself does not offer an in-text amendment log beyond the cross-references listed above.

In short, the AD’s internal amendment history comprises (1) the earlier CASA AD/CESSNA 206/65 which it defers to for already-compliant aircraft; (2) the FAA ADs that precipitated these CASA actions; and (3) the referenced Cessna service bulletins issued in October 2008 which contain the technical steps for inspection and correction.

The AD text supplied does not contain any litigation history. It does not reference court decisions, administrative appeals, or contested enforcement actions. The Background section describes incident reports and FAA/Cessna responses that led to the directive, but no legal challenges or judicial determinations are recorded in the document.

Because no litigation or appeals are referenced in the AD, there is no source material in this text to summarise any judicial or tribunal rulings concerning the validity, scope, or enforcement of AD/CESSNA 206/66. Any litigation that may have occurred after this AD’s issuance is outside the scope of the supplied text and therefore not recorded here. The AD itself is an administrative regulatory instrument; absent other documents or records, the supplied text contains no information on disputes, appeals, or enforcement proceedings taken in relation to it.

Where an operator or maintenance organisation wished to challenge an AD as applied to a specific aircraft, such proceedings would typically be handled under the relevant administrative review or civil aviation appeal mechanisms in force at the time; however, no such proceedings are identified in the AD text. The AD’s references are technical and procedural (service bulletins, FAA ADs, earlier CASA AD), not judicial.

The AD contains several particulars that can generate practical compliance pitfalls if missed or misread.

1. Mixed capture rule that depends on delivery date and parts history. The Applicability combines production date ranges (initial delivery between 1 January 1993 and 31 March 2008) with a parts-installation rule (P/N 2013142-18 installed as a replacement after 1 January 1993). Operators must therefore check both the aircraft’s original delivery date and its maintenance/parts history for replacement selector valves. The AD also carves out aeroplanes that have already had modification/rework required by AD/CESSNA 206/65 and remain in compliance with that AD. Failure to verify the AD/CESSNA 206/65 status could lead to unnecessary inspections or missed obligations.

2. Part number lineage. Note 2 records that P/N 2013142-18 replaced earlier P/Ns 2013142-9, -13 and -17. Parts records that use the earlier P/Ns may therefore mask whether a susceptible 2013142-18 was installed; maintenance records and part tags must be carefully examined to determine which actual valve is installed.

3. Stock and spares risk. Note 1 states the affected parts were shipped from Cessna Parts Distribution between 1 January 1993 and 31 March 2008. That timeframe implies spares inventories in maintenance shops or parts suppliers could include affected valves. Requirement 5 forbids installing P/N 2013142-18 replacement valves after the stated date unless the valve has been inspected and the port is free of obstruction. Maintenance organisations must therefore inspect spares before installation and maintain documentary evidence of that inspection. A misplaced uninspected spare installed after the compliance date would be contrary to the AD.

4. Compliance timing differences between IFR and non-IFR aeroplanes. IFR-equipped aeroplanes face a much shorter compliance window for inspection (10 days) or must install a prohibitive panel placard pre-flight. Operators that fail to plan for that short window may be forced to ground IFR operations or rely on the temporary placard approach, which itself imposes operational limitations.

5. Temporary placard removal requirement. If operators use the temporary placard option for IFR aircraft, Requirement 3 requires removal of the temporary instrument-panel placards after the valve inspection and before further flight. Operators must ensure that temporary placards are not left in place inadvertently once inspection and any corrective action are completed.

6. Exact wording and legibility. The AD requires that temporary placards use at least 1/8-inch letters and include the precise statements "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED". Non-compliant wording or inadequate letter size could fail to meet the AD’s requirement and be treated as non-compliance.

7. Reliance on service bulletins. The AD mandates that the procedures required are detailed in specified Cessna service bulletins (SB08-34-02 Rev 1; CAB08-04 Rev 1; SEB08-5; MEB08-6). If an operator uses a different inspection methodology, the AD’s text suggests the service bulletins are the required source of detail; deviation from the SB procedures could present compliance questions. Operators will need to ensure they use the correct SB that applies to their model and revision version.

8. Document trail for inspectors. Enforcement and oversight may rely on documentary proof that inspections were done in the prescribed windows and that any obstructing placards were removed. Operators must update maintenance records, logbooks and parts records to reflect inspection results, placard installations/removals, and the status of spare valves.

9. Potential for inadvertent reinstatement of obstructive placards. If maintenance personnel or parts suppliers inadvertently fit replacement or identification placards to valve bodies in a way that again obstructs the port, the same hazard reoccurs. Requirement 4 mandates removal and discarding of obstructing part identification placards found during inspection , but preventing recurrence depends on parts-handling discipline and correct installation practices.

10. Lack of explicit penalty or appeal details in the AD. The AD does not specify enforcement penalties or an appeal process in the text provided; operators should not assume any alternative compliance paths exist without engaging CASA. That absence means operators must treat the AD as prescriptive and act within the timelines it sets rather than relying on unspecified deferrals.

These are concrete operational details embedded in the AD that can cause non-compliance if overlooked. The AD’s mixed applicability rule, the P/N history, and the short IFR inspection window are the likeliest sources of practical error.

Compliance with the AD requires documented inspection and, where necessary, correction according to the AD’s Requirements and the referenced Cessna service bulletins. The steps below follow the AD’s structure and timings; operators and maintenance organisations should ensure records are updated in maintenance logbooks and that correct service bulletins are used for the applicable model.

1. Determine applicability.

   • Check the aeroplane’s model against Table 1 in the AD (the AD lists many 206 family variants).
   • Verify the aeroplane’s initial delivery date. If it was initially delivered between 1 January 1993 and 31 March 2008, the AD applies unless the modification/rework required by AD/CESSNA 206/65 has been done and the aeroplane remains in compliance with that prior AD.
   • Check maintenance and parts records for any post-1 January 1993 installation of P/N 2013142-18 as a replacement part. If that part was installed, the AD applies unless the AD/CESSNA 206/65 exception applies.
   • Note that P/N 2013142-18 superseded P/Ns 2013142-9, -13, -17 (Note 2), so verify which physical part number is present, not just historical references.

2. Schedule and perform inspections within the AD’s mandated windows.

   • For non-IFR aeroplanes in the applicability group: perform the valve inspection within the next 100 hours TIS after the AD’s effective date or within the next 4 months after the effective date, whichever occurs first (Requirement 1; Compliance).
   • For IFR-equipped aeroplanes: either (a) perform the same valve inspection within 10 days after the AD’s effective date (Requirement 2a; Compliance), or (b) if immediate inspection is not practicable, fabricate and install a temporary instrument-panel placard stating "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED", using letters at least 1/8-inch high, and place it clearly within the pilot’s field of view (Requirement 2b; Compliance). If option (b) is used, perform the valve inspection within the longer inspection window and remove the temporary placards before further flight (Requirement 3).

3. Conduct the valve port inspection using the detailed steps in the appropriate Cessna service bulletin.

   • The AD identifies the specific Cessna service bulletins that contain the procedures: Single Engine SB08-34-02 Rev 1 (6 Oct 2008), Caravan CAB08-04 Rev 1 (6 Oct 2008), Single Engine SEB08-5 (13 Oct 2008), or Multi-engine MEB08-6 (13 Oct 2008), as applicable. Use the service bulletin that corresponds to your model and follow the inspection and corrective steps precisely.

4. If inspection finds the part number placard obstructing the port:

   • Remove the part number identification placard from the valve body, discard the placard, and assure the port is open and unobstructed before further flight (Requirement 4).
   • Record the action in the aircraft maintenance logbook and any associated part or component history records.

5. If the valve is clear, record the inspection result in the maintenance records, including the date, inspector, and any serial/part numbers for the valve inspected. If temporary IFR placards were installed under Requirement 2b, remove them only after the inspection confirms the valve port is unobstructed (Requirement 3).

6. When installing replacement valves after the specified compliance date:

   • Only install P/N 2013142-18 valves that have been inspected and whose ports were found free from obstruction (Requirement 5 and Compliance: "As of 10 days after the effective date of this AD").
   • For installed replacement parts, maintain documentary proof of the inspection status to demonstrate compliance to auditors and inspectors.

7. Ensure sign-off and record keeping comply with normal maintenance certification requirements.

   • Use the Cessna service bulletin procedures as the method of compliance and record that the SB was used to perform the inspection and any corrective action. Maintain photographs or part tags where helpful to show that the part identification placard was removed and discarded if necessary.

8. For IFR operations during the inspection window:

   • If the operator uses the temporary placard mitigation, ensure the placard is correctly worded and legible (minimum 1/8-inch letters) and located in the pilot’s clear view. Treat the aircraft as not available for IFR flight and as prohibited from use of the alternate static air source until the inspection is complete and any necessary corrective action taken.

9. For spares management and parts procurement:

   • Inspect all P/N 2013142-18 valves in stock before installing them as replacement parts. Keep inspection records for spare valves to avoid inadvertently installing an uninspected valve after the compliance date.
   • Update stock cards and supplier records to reflect inspected status and to prevent re-use of discarded placards or misapplied part identification tags.

10. Liaise with CASA if uncertain.

• The AD provides a prescriptive route to compliance. If an operator cannot comply with the timelines or has an alternative method proposed, the AD text does not set out an exemption mechanism; operators should therefore contact CASA for guidance rather than assume an informal or unrecorded exemption exists.

Practical checklist summary:

• Verify model and delivery/parts history to confirm applicability.
• Use the correct Cessna service bulletin for the model.
• Inspect within the AD’s windows (10 days for IFR inspection, otherwise 100 hours TIS or 4 months).
• If necessary, install the required temporary placard for IFR aircraft before further flight.
• Remove any obstructing placard on the valve body and discard it; ensure valve port is clear before flight.
• Only install inspected P/N 2013142-18 valves as replacements after the stated compliance date.
• Record all inspections and corrective actions in maintenance records.

Following those steps and keeping meticulous records are the concrete compliance path the AD prescribes.