AD/CESSNA 180/94 - Alternate Static Air Source Selector Valve Placard

The AD is built around a small number of technical and procedural concepts grounded in the safety risk that flow logically into duties on operators and maintenance providers.

Affected part and failure mode. The safety issue is a physical obstruction of the alternate static air source selector valve port by a part number identification placard on valve P/N 2013142-18. The AD states this condition "could result in the altimeter, airspeed, and vertical speed indicators displaying erroneous indications" and possibly lead a pilot to react to incorrect flight information, "and possibly result in loss of control" (Background). The AD identifies the affected valve part number and clarifies that P/N 2013142-18 replaced earlier P/Ns 2013142-9, -13 and -17 (Note 2).

Scope and applicability. Applicability is explicit and twofold. First, it applies to the aeroplane models listed in Table 1 that "were initially delivered from the manufacturer between 1 January 1993, and 31 March 2008" unless the modification/rework required in AD/CESSNA 180/93 has been done and the aeroplane remains in compliance with that AD. Second, it applies to any of the aeroplanes that "have a alternate static air selector valve part number (P/N) 2013142-18 installed as a replacement part anytime after 1 January 1993" unless AD/CESSNA 180/93 modification/rework has been done and the aeroplane remains in compliance. The AD also includes a Note that the affected part was shipped from Cessna Parts Distribution between 1 January 1993 and 31 March 2008, which broadens the universe of parts and potential exposure.

Prescriptive actions. The AD prescribes five discrete categories of action. 1) Inspect the selector valve to assure the part number placard is not obstructing the port. 2a) For IFR-equipped aeroplanes, conduct the same inspection within a shorter timeframe (10 days) or, alternatively 2b) fabricate and install a specified temporary placard on the instrument panel stating "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED" in at least 1/8-inch letters. 3) If temporary placards were installed, inspect the valve and then remove the temporary placards before further flight. 4) If the port is found obstructed, remove and discard the placard and ensure the port is unobstructed before further flight. 5) When replacing a valve, only install a P/N 2013142-18 valve that has been inspected and found free from obstruction.

Reference to manufacturer procedures. The AD explicitly defers the detailed procedures for accomplishing the required work to specified Cessna service bulletins: Cessna Single Engine Service Bulletin SB08-34-02 Rev 1 dated 6 October 2008; Cessna Caravan Service Bulletin CAB08-04 Rev 1 dated 6 October 2008; Cessna Single Engine Service Bulletin SEB08-5 dated 13 October 2008; or Cessna Multi-engine Service Bulletin MEB08-6 dated 13 October 2008, "as applicable." That allocation of procedural work means this AD sets the what and when and refers to the manufacturer's how.

Timing and sequencing. The compliance windows are deliberate and variable by aircraft equipage and task: a short 10 day window for IFR-equipped aeroplanes to perform an inspection (or the temporary placard action before further flight), and a longer 100 hours TIS or four months for the inspections required of non-IFR-equipped aeroplanes and for the follow-up inspection if temporary placards were used. The AD also imposes an effective date (16 January 2009) and an operational prohibition on installing replacement valves unless inspected, effective 10 days after that date.

Chain of authority and cross-jurisdictional references. The AD arises from reports that prompted FAA action and references FAA ADs,FAA AD 2008-10-02, and a later FAA AD 2008-26-10 Amdt 39-15776 dated 15 December 2008. It also cross-references CASA AD/CESSNA 180/93. The issuer is the Civil Aviation Safety Authority, and the document is signed by James Coyne, Delegate of CASA.

Record and spares considerations. The AD’s Note that parts were shipped by Cessna Parts Distribution over a 15 year period indicates that not only installed valves but spares may be affected. The AD therefore affects both in-service equipment and spare-stock inspection and replacement practices. The AD’s Requirement 5 (only install P/N 2013142-18 valves that have been inspected and found unobstructed) directly constrains the use of spare parts that have not been inspected.

In short, the AD operationalises a risk mitigation for an identified hardware installation problem by (1) identifying the affected population of aeroplanes and parts, (2) mandating inspection and conditional placarding to block IFR operation where necessary, (3) requiring removal of any obstructing placard, and (4) constraining installation of replacement valves to inspected parts, with the procedural details to be followed per the referenced Cessna service bulletins.

The AD names a defined set of aeroplane models and, through the phrasing of applicability notes, affects multiple classes of stakeholders within the civil aviation supply chain.

Aircraft owners and operators. Operators of any of the models listed in Table 1 who meet the date-of-delivery criterion (initially delivered between 1 January 1993 and 31 March 2008) are directly affected unless they have earlier performed the modification/rework required by AD/CESSNA 180/93 and remain in compliance with that AD. Operators who have installed P/N 2013142-18 valves as replacement parts at any time after 1 January 1993 are also affected, again subject to the AD/CESSNA 180/93 exception. For IFR-equipped operators, the AD imposes immediate short-term action windows and may impose operational constraints via the temporary placard stating "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED" (Requirement 2b). The AD therefore affects flight planning and operations for IFR-equipped operators of affected aeroplanes until the inspection and any necessary corrective action are done.

Maintenance organisations and licensed engineers. The AD requires physical inspections of the selector valve port to "assure that the part number identification placard is not obstructing the port" (Requirements 1, 2a, 3). This imposes work on maintenance organisations and licensed persons responsible for carrying out or certifying inspections and any removal/discard of an obstructing placard (Requirement 4). These entities will also need to follow the detailed procedures contained in the listed Cessna service bulletins to accomplish the AD.

Part suppliers, part stockholders and distribution centres. The AD notes the affected part "was shipped from Cessna Parts Distribution (CPD) between 1 January 1993, and 31 March 2008" (Note 1) and that P/N 2013142-18 replaced earlier P/Ns (Note 2). That means parts inventories, warehouses, repair stations and spares distribution chains holding P/N 2013142-18 valves must inspect spare valves and be prepared to withhold installation of uninspected P/N 2013142-18 valves because Requirement 5 restricts installation of replacement valves to only those that have been inspected and found unobstructed. CASA also expressly notes that CASA "has no way of determining which aeroplanes have the remaining problem ... installed without having all of the affected aeroplanes and spares stock inspected" (Background), which highlights that stockholders and parts managers are within the affected group.

Pilots, especially IFR pilots. The AD directly affects pilot operating conditions, in particular IFR-equipped pilots of affected aeroplanes. If the temporary placard required by Requirement 2b is fitted, it displays "IFR OPERATION IS PROHIBITED," which is an operational restriction placed in the pilot’s clear view on the instrument panel. Even where the placard is not installed, the inspection and corrective actions are intended to prevent instrument error that could lead to erroneous altimeter, airspeed, and vertical speed indications. Thus the AD affects pilot decision-making, flight rules utilisation and pre-flight checks.

Regulators and certifying authorities. CASA is the issuer and is identified by name and signature, and the AD references FAA actions. CASA's statement that it cannot determine which aeroplanes have the affected valves without inspection indicates CASA is relying on the operators and maintenance community to execute the necessary inspections and corrections. CASA also delegates the detailed procedural steps to the manufacturer's service bulletins, so regulatory oversight will involve verifying AD compliance via those bulletins.

Manufacturers and OEM service organisations. Cessna is implicated because the AD points to Cessna service bulletins for the procedures to accomplish the inspection and corrective actions. Cessna Parts Distribution is noted as the distribution source for the affected parts between specified dates. Therefore, Cessna and its authorised service organisations may need to support operators and parts holders in locating, inspecting and, where necessary, correcting or replacing affected valves.

Insurance and third-party stakeholders. The AD creates an obligation on operators and certifying maintenance organisations that may interact with insurance underwriting and claims processing, since non-compliance with an AD could have implications in the event of an incident. The AD does not itself mention insurers, but the imposition of mandatory inspections and temporary placarding will be of practical relevance to insurers and risk managers.

In summary, the AD affects a network of actors: operators and pilots of specified Cessna models, maintenance organisations, parts distributors holding P/N 2013142-18, Cessna service and parts operations, and CASA as regulator. The AD’s applicability language means that aeroplanes outside the stated delivery date window can still be affected if a P/N 2013142-18 valve was installed as a replacement after 1 January 1993, thereby enlarging the practical set of affected aeroplanes beyond the original production-delivery date cohort.

The AD sets out affirmative duties for affected operators and maintenance organisations. It prescribes specific actions to be performed, with distinct timing, and references the service bulletins for the procedural how-to. The AD does not enumerate express rights, remedies or appeal mechanisms within its text, but it defines a set of mandatory duties and operational constraints for compliance.

Duties under the AD. The AD contains five numbered Requirements which create the primary duties:

• Requirement 1. For all affected aeroplanes that are not equipped for flight under instrument flight rules (IFR), inspect the alternate static air source selector valve to assure that the part number identification placard is not obstructing the port. The compliance window for Requirement 1 is within the next 100 hours TIS after the effective date of the AD or within the next 4 months after the effective date, whichever occurs first.

• Requirement 2. For all affected aeroplanes that are equipped for IFR: either 2a) inspect the alternate static air source selector valve to assure that the part number identification placard is not obstructing the port (to be done within 10 days after the effective date of the AD), or 2b) fabricate a placard containing the exact words "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED" in at least 1/8-inch letters and install it on the instrument panel within the pilot's clear view, before further flight after the effective date of the AD. The AD requires placement of the specified warnings in the pilots’ field of view to ensure the crew are informed of the potential hazard while pending inspection.

• Requirement 3. For IFR-equipped aeroplanes where placards were installed per Requirement 2b, inspect the alternate static air source selector valve within the same 100 hours TIS or 4 month window as Requirement 1. After that inspection, remove the temporary placards installed per Requirement 2b before further flight.

• Requirement 4. For all affected aeroplanes, if during any inspection required in Requirements 1, 2a, or 3 the alternate static air source selector valve port is found obstructed by the part number identification placard, remove the placard from the valve body, discard the placard, and assure that the port is open and unobstructed. This must be completed before further flight.

• Requirement 5. For all affected aeroplanes, when a replacement valve is needed, install only a P/N 2013142-18 valve that has been inspected and the port found free from obstruction. This requirement is effective as of 10 days after the effective date of the AD.

Procedural delegation. The AD does not prescribe the detailed nuts and bolts of how to carry out the inspections and removals in the AD text; rather the AD requires adherence to the detailed procedures described in the relevant Cessna service bulletins listed in the AD. This channels technical compliance into manufacturer-specified procedures, which are cited verbatim in the AD.

Operational duty effects. For IFR-equipped aeroplanes, the AD imposes an operational constraint in practice: unless the shorter inspection (Requirement 2a) is completed within 10 days, the operator must install the specified temporary placard before further flight, which contains a prohibition on IFR operation and on the use of the alternate static air source. The temporary placard must be removed after the inspection per Requirement 3 before further flight. Thus operators face a choice of performing an inspection quickly or adopting the operational restriction via placard until the inspection can be performed.

Recordkeeping and evidentiary burdens. The AD itself does not detail recordkeeping obligations or certification entries; however, compliance logically requires maintenance entries or other documentary evidence demonstrating that the inspections and any corrective actions occurred within the compliance windows. The AD explicitly refers to service bulletins for procedures, which likely include recommended recordkeeping, but the AD text itself does not state those obligations.

Rights, limitations and exemptions stated in the AD. The AD includes an express exemption built into the applicability: aeroplanes that have already had the modification/rework required in AD/CESSNA 180/93 done and "remain in compliance with that AD" are exempt from these applicability criteria. The AD also limits the availability of replacement valves for installation to those P/N 2013142-18 valves that have been inspected and found unobstructed, thereby restricting parts installation as a compliance mechanism.

Absence of penalty clauses. The AD does not include penalties or enforcement language in its text. It prescribes mandatory actions and compliance times but does not include specific sanctioning language within the AD itself. Enforcement and sanctioning mechanisms applicable to AD non-compliance are not set out in the AD.

In summary, the AD creates distinct duties to inspect, placard temporarily (for IFR-equipped aeroplanes) or inspect quickly, remove obstructing placards before further flight, and restrict installation of replacement parts unless inspected. The AD delegates procedural detail to Cessna service bulletins. The AD contains a narrow exemption for aeroplanes compliant with an earlier CASA AD (AD/CESSNA 180/93). The AD does not, in its text, enumerate penalties, specific recordkeeping forms, or appeal processes.

The AD prescribes mandatory corrective and preventive actions, and fixed compliance windows, but the text of the AD itself does not specify monetary penalties, civil sanction amounts, criminal offences or the specific enforcement mechanism to be applied for non-compliance. The AD is explicit about required actions and timelines, yet it contains no enumerated penalty provisions in its body.

What the AD does set out. The instrument specifies the actions required (inspections, placarding, removal/discard of obstructing placards, and restrictions on installing replacement valves) and sets firm compliance windows for each requirement. It also sets an effective date, 16 January 2009, and notes the AD becomes effective on that date. The AD is issued by CASA and signed by a CASA delegate, James Coyne. That administrative formality identifies the issuing authority and the effective date of the mandatory requirements.

What the AD does not set out. The AD contains no text establishing the legal consequences or penalty regime for failure to comply with the AD. It does not specify which regulatory instrument or statute provides the enforcement power, nor does it identify the forms of sanction, administrative or criminal, that might be used for non-compliance. The AD likewise does not identify any appeals process, compliance relief mechanism, or alternatives to the listed requirements within the text (other than the alternative actions specified for IFR-equipped aeroplanes and the exemption for aeroplanes compliant with AD/CESSNA 180/93).

Inference and operational reality. Although the AD is silent on penalties within its own text, operators should treat the AD as a mandatory safety requirement issued by the national aviation safety authority. The AD sets fixed deadlines and instructs that certain operations be prohibited by temporary placard language (for IFR-equipped aeroplanes) until inspections are carried out. Consequently, failure to meet these requirements is likely to have regulatory consequences administered by the authority charged with aviation safety oversight. The AD itself does not describe those consequences.

Enforcement implication for operations and maintenance. Because the AD requires pre-flight operational changes (e.g. installation of a placard that prohibits IFR operation and use of the alternate static source), and requires removal of an obstructing placard before further flight, operators must either complete the inspections or adopt the interim limitations. Those operational constraints can have immediate effects on flight planning and service delivery. From an enforcement perspective, a regulator performing an audit or investigating an incident could consider compliance with applicable ADs when assessing whether required maintenance and directives were complied with, but the AD text does not articulate that linkage.

Interaction with certification and continuing airworthiness. The AD references manufacturer service bulletins for procedural detail. Compliance with the AD necessarily implicates continuing airworthiness activities and the paperwork and certification entries that flow from maintenance actions. The AD itself does not set those paperwork requirements but implementing the required tasks will typically produce certifying entries in the maintenance release or logbooks that demonstrate compliance. Those entries would be central to any enforcement inquiry, though the AD does not state that explicitly.

Summary. The AD establishes mandatory technical and operational requirements and specific compliance dates, but it does not include within its text a penalty schedule or detailed enforcement procedures. The existence of mandatory requirements and clearly stated compliance windows places a practical enforcement expectation on affected operators, maintenance organisations and parts holders, but details of sanctions and enforcement processes are not provided in the AD document itself.

The AD expressly cross-references prior and parallel regulatory and manufacturer actions, and it embeds those external instruments as part of its compliance framework. The AD does not attempt to restate the content of those instruments, but it relies on them for applicability exemptions and procedural detail.

Reference to prior CASA AD. The applicability language includes an express exception for aeroplanes that "were initially delivered ... unless the modification/rework required in AD/CESSNA 180/93 has been done and the aeroplane remains in compliance with that AD." This makes compliance with AD/CESSNA 180/93 a condition that can remove an aeroplane from the scope of AD/CESSNA 180/94. Thus the AD operates in coordination with earlier CASA directives and treats the earlier AD as capable of curing or superseding the unsafe condition insofar as particular aeroplanes have had the required modification/rework.

Reference to FAA ADs. The AD notes it was prompted by the FAA issuing AD 2008-10-02, and explicitly states that FAA AD 2008-26-10 Amdt 39-15776 dated 15 December 2008 "refers" (Note 3). The Background explains that the FAA received reports of 15 aeroplanes with obstructed ports and that the affected part was shipped by Cessna Parts Distribution in a defined period. By referencing FAA ADs, the CASA AD situates itself within a cross-jurisdictional safety response; it aligns CASA mandated actions to address a condition already identified by the FAA and which manifested in FAA-regulated aircraft.

Dependence on manufacturer service bulletins. The AD requires that the procedures "required to accomplish this AD are detailed in" certain Cessna service bulletins and lists specific service bulletin identifiers and dates. This is a standard regulatory pattern where the AD sets the mandatory requirement and the manufacturer service bulletin provides the detailed technical method. The AD therefore interacts with the manufacturer's technical documentation as the operative procedural standard for accomplishing inspections, removals and any corrective acts.

Parts distribution and supply chain coverage. The AD’s Note that the affected part "was shipped from Cessna Parts Distribution between 1 January 1993 and 31 March 2008" means the AD reaches beyond installed equipment to spare parts held across jurisdictions. That interaction creates an indirect regulatory effect on parts distributors and warehouses. A parts distributor or a repair station that installs a P/N 2013142-18 valve after the effective date must ensure the valve has been inspected and found unobstructed before installation, consistent with Requirement 5.

Operational rule interactions. The AD itself sets an operational limitation via the temporary placard for IFR-equipped aeroplanes: the placard contains the words "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED." While the AD does not restate higher-level instrument flight rule provisions or certification standards, by prohibiting IFR operation on an affected aeroplane via placard content it produces an immediate operational effect that interacts with flight rules. Crew compliance with aeroplane placarding is part of standard operating procedures and regulatory compliance regimes.

No explicit reference to civil aviation statute or enforcement regulations. The AD does not cite the statutory provisions that give CASA the power to issue ADs or set out enforcement mechanisms or penalties within the AD itself. It therefore interacts with the broader body of civil aviation law and enforcement practice by implication rather than by explicit citation in the AD text.

Summary. The AD operates in a network of normative instruments: it is conditioned by an earlier CASA AD, it responds to and cross-references FAA ADs, it requires the use of Cessna service bulletins for procedural detail, and it affects the handling and use of spares supplied by Cessna Parts Distribution. The AD thus coordinates with other regulatory and manufacturer instruments to deliver a targeted safety remediation, although it does not in its text restate the statutory bases for CASA power or enforcement mechanisms.

The AD itself includes multiple embedded references and notes that reflect a chain of actions, both regulatory and manufacturer-issued, that led to the issuance of AD/CESSNA 180/94. While the AD text does not include a conventional amendment log with successive versions of the CASA AD, it cites antecedent instruments and service bulletins with dates and revision numbers. Those references provide the practical amendment and action history relevant to this safety issue.

Key antecedent instruments and events referenced in the AD:

• AD/CESSNA 180/93. The present AD explicitly conditions applicability on whether the modification/rework required in AD/CESSNA 180/93 "has been done and the aeroplane remains in compliance with that AD." That indicates an earlier CASA AD addressed a related matter and that compliance with that earlier AD may obviate the need for the present directive on a particular aeroplane.

• FAA AD 2008-10-02. The AD states it was issued "in response to the United States Federal Aviation Administration (FAA) issuing AD 2008-10-02." This indicates the CASA action followed an FAA identification of the unsafe condition. The AD does not reproduce the FAA AD text but acknowledges the FAA action as the initiating external trigger.

• Cessna service bulletins. The AD identifies the specific Cessna service bulletins that detail the procedures required to accomplish the AD: Cessna Single Engine Service Bulletin SB08-34-02, Revision 1, dated 6 October 2008; Cessna Caravan Service Bulletin CAB08-04, Revision 1, dated 6 October 2008; Cessna Single Engine Service Bulletin SEB08-5, dated 13 October 2008; and Cessna Multi-engine Service Bulletin MEB08-6, dated 13 October 2008. Those bulletins, two of which are revisions dated 6 October 2008, appear to have been issued in the lead-up to the FAA action and the CASA AD.

• FAA AD 2008-26-10 Amdt 39-15776 dated 15 December 2008. The AD includes Note 3 which states that the FAA AD 2008-26-10 refers. The inclusion of this later FAA amendment suggests additional FAA action referencing the condition and may reflect an expanded or updated FAA response in December 2008.

• CASA AD effective and issue dates. The AD states that it "becomes effective on 16 January 2009." The AD document itself bears the date 8 January 2009 and is signed by James Coyne, Delegate of the Civil Aviation Safety Authority. The sequence is therefore: Cessna service bulletins dated 6 and 13 October 2008, FAA ADs in 2008 (including a December 2008 amendment), CASA issue date 8 January 2009, and CASA effective date 16 January 2009.

Parts and distribution notes. The AD contains technical notes that function as part of the amendment history of the affected part. Note 1 records that "The affected part was shipped from Cessna Parts Distribution (CPD) between 1 January 1993 and 31 March 2008." Note 2 states "P/N 2013142-18 replaced P/Ns 2013142-9, -13, and -17." Those notes provide a historical anchor for the part numbering and the distribution window for the potentially affected valves.

Background event counts. The Background includes the operational detail that the FAA "has received reports of 15 aeroplanes not previously affected by AD 2008-10-02 with a P/N 2013142-18 installed and the alternate static air source selector valve port was found obstructed." That count of reported instances is part of the factual history that prompted the AD.

Absence of subsequent CASA amendments in the AD text. The AD document does not itself contain any subsequent amendments to AD/CESSNA 180/94; it presents the directive in its operative form as of 16 January 2009. There is no in-text amendment log of later CASA revisions to this specific AD.

Practical implication of the amendment chain. The AD functions as a final step in a chain: manufacturer service bulletins issued in October 2008; FAA AD action in 2008 and a December amendment; CASA's analysis and inability to determine which aeroplanes had affected parts without inspection; and then CASA issuing AD/CESSNA 180/94 effective 16 January 2009. On the parts side, the history of P/N replacement names and the CPD shipping window provides the practical trace needed to identify affected stock and installations.

The AD text contains no litigation history. It does not reference any court decisions, appeals, or legal proceedings associated with the subject matter. There are no cases cited within the AD, and no mention of any legal challenge to either CASA or FAA actions.

What the AD does document is administrative action and technical facts: service bulletins issued by Cessna, FAA ADs that prompted the CASA response, 15 reports to the FAA of obstructed valve ports, and the issuance of AD/CESSNA 180/94 by CASA, signed 8 January 2009 and effective 16 January 2009. The Background provides factual rationale and references to prior regulatory acts but does not record any litigation.

Implication for practitioners and researchers. Because the AD contains no litigation references, practitioners seeking judicial treatment, case law interpretation, or precedential decisions related to this AD will need to look beyond the AD text to court databases, administrative tribunals or records of enforcement actions that are not reproduced in the AD. The AD itself functions as a technical regulatory instrument without commentary on legal disputes or adjudication arising from it.

In the absence of litigation references in the AD, any legal analysis of enforcement, disputes over compliance, or liability arising from incidents referencing this AD must be based on external legal materials and case law, which are not provided in this AD document.

The AD contains a number of practical traps and subtleties that can lead to non-compliance, operational disruption, or misunderstanding if not carefully read and implemented. These are directly traceable to the AD wording and its interaction with parts distribution, service bulletins and earlier ADs.

Applicability is not limited to delivery date. A common misread would be to assume only aeroplanes delivered between 1 January 1993 and 31 March 2008 are affected. The AD also applies to any aeroplane that "has a alternate static air selector valve part number (P/N) 2013142-18 installed as a replacement part anytime after 1 January 1993." That means aircraft delivered outside the delivery window can still be affected if a P/N 2013142-18 replacement valve was installed. Practically, operators must check the installed part number history, not just the aircraft delivery date.

Spare parts stock must be considered. Note 1 states the affected parts were shipped by Cessna Parts Distribution between 1 January 1993 and 31 March 2008. The AD explicitly notes CASA does not have a way of determining which aeroplanes and spares stock have the affected valves "without having all of the affected aeroplanes and spares stock inspected." Therefore parts warehouses, spares managers and repair stations holding P/N 2013142-18 valves must inspect stock before installation. Requirement 5 restricts installation of replacement valves to those that have been inspected and found unobstructed as of 10 days after the effective date.

Temporary placard paradox. For IFR-equipped aeroplanes, the AD offers a two-path approach: either perform the inspection within 10 days (Requirement 2a), or fabricate and install a temporary placard prohibiting IFR operation and use of the alternate static source before further flight (Requirement 2b). Requirement 3 then requires the inspection within the longer 100 hours TIS or 4 months window and, after that inspection, the placards installed under 2b must be removed before further flight. The gotcha is that an operator who fits the temporary placard must remember it is temporary and remove it after inspection; conversely, installation of the placard before inspection will restrict IFR operations pending inspection. Operators must understand this sequence and ensure they do not inadvertently operate IFR while a placard is in place or forget to remove the placard after inspection when the port is clear.

Exact placard wording and size requirement. Requirement 2b prescribes specific text and a minimum letter size: the placard must incorporate the words "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED," using at least 1/8-inch letters. Failure to use the exact words or to meet the minimum letter size could be treated as non-compliant with the AD. The AD also specifies placement "on the instrument panel within the pilot’s clear view," so placement matters.

Ambiguity around "assure." The AD repeatedly requires inspection "to assure that the part number identification placard is not obstructing the port." The AD does not define what level of inspection is required (visual only, disassembly of valve, etc.), but defers to the Cessna service bulletins for procedural details. Practitioners must therefore follow the referenced service bulletin procedures; relying on cursory visual checks that do not follow the service bulletin could risk non-compliance.

Replacement valve installation restriction. Requirement 5 states that when a replacement valve is needed, "only install a P/N 2013142-18 alternate static air source selector valve that has been inspected and the port is found free from obstruction." The gotcha is that this is effective 10 days after the effective date, so supply chains and shops that would normally install replacement P/N 2013142-18 valves must ensure those parts were inspected before installation. Installing a valve from stock that has not been inspected could violate the AD after the 10 day threshold.

Interplay with AD/CESSNA 180/93. The applicability exception for aeroplanes compliant with AD/CESSNA 180/93 can be a source of confusion. Operators must verify not only whether the earlier AD’s modification/rework was performed but also that the aeroplane "remains in compliance with that AD." The AD does not elaborate on how continuing compliance is to be evidenced; operators should verify maintenance records and any applicable certification or sign-off required under AD/CESSNA 180/93 to confirm the exemption applies.

Service bulletin applicability. The AD lists multiple Cessna service bulletins with different identifiers and dates and states procedures are detailed in those bulletins "as applicable." Operators must identify which service bulletin applies to their specific aeroplane and model variant (single engine, caravan, multi-engine, etc.). Applying the incorrect service bulletin procedures or misidentifying which bulletin is applicable to a particular model could lead to incorrect inspections or remedial actions.

Record and proof requirements not explicit. The AD does not specify the documentary proof needed to demonstrate compliance. Operators should be aware that inspectors or auditors will expect maintenance records and entries. A failure to create or retain maintenance entries that prove inspection and corrective action falls within the compliance windows could present enforcement or insurance risk, even though the AD does not itself specify the paperwork.

Timing consequences for operations. For IFR-equipped aeroplanes, the 10 day inspection window is short. Operators with limited maintenance access may need to adopt the temporary placard option, but that carries the operational constraint of prohibiting IFR flight. Failure to plan for these constraints could disrupt scheduled flights.

Summary. The main gotchas are: don’t rely on delivery date alone, inspect spare valves in stock, follow exact placard wording and letter size requirements, adhere to the precise compliance windows and sequencing (especially for IFR-equipped aeroplanes), confirm applicability with respect to AD/CESSNA 180/93, and use the correct Cessna service bulletin. Failure to navigate these subtleties can lead to operational restrictions or non-compliance.

The AD sets out a clear compliance path in five Requirements and delegates technical procedures to specified Cessna service bulletins. The following is a practical, source-grounded checklist and sequence that follows the AD’s text verbatim, organised for operational use. Operators and maintenance organisations must follow the AD requirements and the referenced service bulletins for the procedural details.

Step 0 , Establish applicability. Confirm whether the aeroplane is one of the models listed in Table 1 of the AD. Then determine whether either of the two applicability criteria is met:

• The aeroplane was initially delivered from the manufacturer between 1 January 1993 and 31 March 2008, unless the modification/rework required in AD/CESSNA 180/93 has been done and the aeroplane remains in compliance with that AD; or
• The aeroplane has a P/N 2013142-18 alternate static air selector valve installed as a replacement part anytime after 1 January 1993, unless AD/CESSNA 180/93 modification/rework has been done and the aeroplane remains in compliance with that AD.

If neither criterion is met, the AD does not apply. If either criterion is met, proceed.

Step 1 , Identify equipment fit and urgent timing. Determine whether the aeroplane is equipped for flight under instrument flight rules (IFR).

• If the aeroplane is IFR-equipped, the AD provides two alternative immediate actions (Requirement 2): 2a) inspect the alternate static air source selector valve within 10 days after the AD effective date; or 2b) fabricate and install the specified temporary placard "before further flight" after the AD effective date. Decide which path is operationally feasible.
• If the aeroplane is not IFR-equipped, the inspection required by Requirement 1 must be scheduled within the longer window of 100 hours TIS or 4 months after the effective date, whichever occurs first.

Step 2 , Follow the required inspection. The AD requires inspection "to assure that the part number identification placard is not obstructing the port." For the precise steps, use the applicable Cessna service bulletin:

• For single-engine aeroplanes: Cessna Single Engine Service Bulletin SB08-34-02, Revision 1, dated 6 October 2008, or SEB08-5 dated 13 October 2008 as applicable.
• For Caravan models: Cessna Caravan Service Bulletin CAB08-04, Revision 1, dated 6 October 2008.
• For multi-engine models: Cessna Multi-engine Service Bulletin MEB08-6, dated 13 October 2008. Use the bulletin that applies to the aeroplane model. Do not substitute an inspection methodology that departs from the applicable service bulletin procedures without authorised alternative approval.

Step 3 , Implement the temporary placard procedure if required. If IFR-equipped and the inspection cannot be completed within 10 days, fabricate and install a placard that incorporates the following words using at least 1/8-inch letters: "IFR OPERATION IS PROHIBITED" and "USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED." Install this placard on the instrument panel within the pilot’s clear view before further flight. This is Requirement 2b. Remember that if this temporary placard is fitted, Requirement 3 imposes a subsequent inspection within the 100 hours/4 months window.

Step 4 , Address any obstruction found. If the inspection (Requirements 1, 2a, or 3) finds that the valve port is obstructed by the part number identification placard, remove the placard from the valve body, discard the placard, and assure that the port is open and unobstructed. This must be done before further flight (Requirement 4). Follow the detailed removal and verification steps in the applicable Cessna service bulletin.

Step 5 , Remove temporary placard after inspection. If the temporary placard was installed under Requirement 2b, perform the inspection called for in Requirement 3 within the next 100 hours TIS or within the next 4 months after the effective date of the AD, whichever occurs first. After completing that inspection, remove the temporary placards installed under Requirement 2b before further flight.

Step 6 , Replacement valve installation limitation. If a replacement valve is needed, do not install a P/N 2013142-18 valve unless that particular valve has been inspected and the port found free from obstruction. This restriction applies for replacements installed after 10 days from the AD’s effective date (Requirement 5). Therefore, check spare valve stock and ensure inspection and removal of any obstructing placard prior to installation.

Step 7 , Use the service bulletins for procedural detail. The AD explicitly states that "The procedures required to accomplish this AD are detailed in" the listed Cessna service bulletins and cites the bulletin identifiers and dates. Obtain the relevant bulletin and follow its step-by-step procedures. If there is any uncertainty as to which service bulletin applies, select the bulletin that corresponds to the aeroplane model and configuration.

Step 8 , Timing adherence. Observe the AD’s compliance timing:

• Requirement 1 (non-IFR aeroplanes): within the next 100 hours TIS or within the next 4 months after the effective date, whichever occurs first.
• Requirement 2a (IFR inspection): within 10 days after the effective date of the AD.
• Requirement 2b (temporary placard): before further flight after the effective date if choosing placard option.
• Requirement 3 (inspection after placard): within the next 100 hours TIS or within the next 4 months after the effective date, whichever occurs first; after the inspection remove placards before further flight.
• Requirement 4 (remove obstructing placard): before further flight after the inspection that reveals obstruction.
• Requirement 5 (replacement valve installation): effective as of 10 days after the effective date; only install P/N 2013142-18 valves that have been inspected and found unobstructed.

Step 9 , Consider spares and supply chain. Inspect any P/N 2013142-18 valves held in spares inventory that were shipped from Cessna Parts Distribution in the period 1 January 1993 to 31 March 2008 as the AD’s Note 1 identifies that shipping window as the period during which affected parts may have been supplied. Do not install P/N 2013142-18 valves from stock unless inspected and found unobstructed in accordance with the AD.

Step 10 , Documentation and audit trail. Although the AD does not specify particular recordkeeping language, create and retain maintenance entries, inspection reports and records of placard fabrication and installation/removal. Document the part number verification of installed valves. Keep references to the Cessna service bulletin used to accomplish the procedure. Retained documentation will be essential to demonstrate compliance in an audit or incident investigation.

Step 11 , Cross-check with AD/CESSNA 180/93. Before treating an aeroplane as affected, verify whether the modification/rework required in AD/CESSNA 180/93 has already been done and whether the aeroplane remains in compliance with that AD. If the aeroplane is compliant with AD/CESSNA 180/93, that compliance may remove the aeroplane from the applicability of the present AD per its explicit language.

Step 12 , Keep abreast of related FAA or CASA advisories. The AD notes FAA ADs that relate to the condition, including FAA AD 2008-10-02 and FAA AD 2008-26-10 Amdt 39-15776 dated 15 December 2008. Monitor any subsequent FAA or CASA guidance or amendments that might refine the inspection procedures or compliance expectations.

In short, compliance requires verification of applicability, timely inspection per the AD and the applicable Cessna service bulletin, temporary placarding for IFR-equipped aeroplanes if an immediate inspection is not possible, removal and discard of any obstructing placard before further flight, cessation of installing uninspected P/N 2013142-18 valves as replacements, and thorough documentation of all actions taken.