AD/CESSNA 336/15 - Alternate Static Air Source Selector Valve Placard

Alternate static air source selector valve. This is a component in certain Cessna 336 aeroplanes that allows the pilot to select an alternate source of static air for the pitot‑static system, typically used if the primary static port becomes blocked. The valve has a port through which air flows. The AD specifically concerns the identification placard affixed to the valve body.

P/N 2013142-18. This part number identifies the specific valve assembly that is the subject of the AD. The Background explains that P/N 2013142-18 replaced earlier part numbers 2013142-9, -13, and -17. The AD covers both original delivery and replacement installations of this part.

Part number identification placard. This is a small label attached to the valve body that shows its part number for identification purposes. According to the AD, if that placard is improperly positioned, it can physically block the air port on the valve.

IFR (Instrument Flight Rules). The AD distinguishes between aeroplanes that are equipped for flight under IFR and those that are not. IFR‑equipped aeroplanes have the necessary instrumentation and systems to fly solely by reference to instruments in reduced visibility. The AD imposes more urgent and more complex requirements on IFR‑equipped aircraft because an erroneous static air source reading is more likely to lead to loss of control when the pilot cannot rely on visual references. The temporary placard under Requirement 2b effectively prohibits IFR operation and use of the alternate static air source pending a physical inspection.

Placard obstruction. The condition the AD seeks to correct. An obstruction occurs when the part number identification placard is positioned such that it blocks or restricts air flow through the valve port. The AD does not specify how to determine obstruction beyond a visual inspection; the detailed procedure is in the referenced service bulletins.

Time‑in‑service (TIS). This is a measure of aircraft usage defined by flight hours. The AD uses 100 hours TIS as one trigger for compliance, alongside a calendar‑based trigger of four months. The earlier of the two applies.

Before further flight. A compliance deadline meaning the action must be completed prior to the next flight after the trigger event (here, after the effective date or after the inspection). This carries significant operational implications because it can ground the aircraft if the required action is not performed.

Airworthiness Directive. An AD is a legally enforceable notification issued by the national aviation authority (CASA in Australia, FAA in the United States) requiring corrective action on an aircraft, engine, or component to maintain its airworthiness. Non‑compliance with an AD makes the aircraft unairworthy.

Delegate of CASA. The AD is signed by James Coyne, a Delegate of the Civil Aviation Safety Authority. This means the AD is an official CASA instrument, not merely an advisory bulletin.

FAA AD 2008-26-10. The AD notes that it refers to this FAA airworthiness directive. The Background references an earlier FAA AD 2008-10-02 that addressed a similar issue on other Cessna models. This shows that the problem had been known since at least May 2008 and that the FAA and CASA were coordinating, albeit with an expansion to models previously thought unaffected.

The primary group affected is the owners and operators of Cessna 336 model aeroplanes that fall within the applicability date ranges. That includes all such aeroplanes originally delivered between 1 January 1993 and 31 March 2008. Given the model’s production run, this likely captures a large proportion of the Cessna 336 fleet in Australia. Secondary affected persons are any owners or operators who have installed a P/N 2013142-18 replacement valve at any time after 1 January 1993, regardless of the original delivery date.

Maintenance organisations and licensed aircraft maintenance engineers (LAMEs) are also affected because they will be the ones performing the inspections, placard installations, and removals. The AD references specific service bulletins that contain the detailed procedures; those bulletins must be obtained and followed. This creates a demand for the bulletins and for the labour time to execute the steps.

Cessna Parts Distribution (CPD) is affected because the AD notes that all valves shipped from CPD between 1 January 1993 and 31 March 2008 may have the obstruction problem. The AD effectively imposes a quality‑control issue on CPD and Cessna, though the compliance burden falls on aircraft owners. The Background states that CASA has no way of determining which aeroplanes have the affected valves without inspecting all of them. This means no reliance on historical records; every aeroplane within the broad applicability must be inspected.

Operators who use the aircraft for hire or reward, flight training, or charter operations may face more acute economic consequences because any grounding or delay affects revenue. The AD’s compliance deadlines create scheduling pressure. For non‑IFR aircraft, the 100‑hour/4‑month window allows maintenance to be scheduled at the next regular inspection. For IFR aircraft, the ten‑day window for option 2a requires prompt action. Option 2b (immediate placard installation before further flight) can be done quickly with minimal cost, but then imposes a second inspection later, meaning two maintenance visits for what could have been a single inspection under option 2a.

Parts suppliers and stockists of P/N 2013142-18 are also affected. As of ten days after the effective date, any unsold valve in stock that has not been inspected for obstruction cannot be sold for installation. They must either inspect the stock or discard it. This places a one‑time cost on the supply chain, as well as a risk that some valves may be found obstructed and must be scrapped.

The AD also indirectly affects insurers, lessors, and potential buyers of affected aeroplanes, because compliance records will be scrutinised during transactions. An aircraft that lacks a logbook entry showing compliance with AD/CESSNA 336/15 may be considered unairworthy, reducing its value and marketability.

Duty to inspect. The AD imposes four distinct inspection duties depending on the aeroplane’s IFR status and the compliance path chosen. For non‑IFR aeroplanes, the duty under Requirement 1 is to inspect the valve within 100 hours TIS or four months, whichever comes first. For IFR aeroplanes, the operator may either inspect within ten days (Requirement 2a) or install the prohibitory placard before further flight (Requirement 2b). If placard under 2b is chosen, the operator must still conduct a later inspection within 100 hours TIS or four months (Requirement 3). In practice, the placard path may be selected if the aircraft cannot be grounded for a physical inspection within ten days, but the trade‑off is that the operator must arrange two maintenance events: one for placarding and a later one for inspection and placard removal.

Duty to remove obstruction. Requirement 4 imposes a duty to remove and discard the obstructing placard from the valve body and to verify that the port is unobstructed. This must be done before further flight after discovering the obstruction. It applies whether the obstruction was found during the initial inspection or the follow‑up inspection.

Duty to use only inspected valves for replacements. Requirement 5 prohibits installation of a P/N 2013142-18 valve unless it has been inspected and found free from obstruction. This duty applies to all affected aeroplanes and takes effect ten days after the effective date. It thus applies not only to the current fleet but to any future maintenance actions.

Right to choose between compliance paths for IFR aircraft. For IFR‑equipped aeroplanes, the operator has a choice: inspect the valve within ten days (2a) or install the placard before further flight and then inspect at a later date (2b). The right exists, but it is not cost‑free; choosing 2b imposes an extra compliance step (placard removal) and may be more expensive overall due to the additional labour required for two visits. Moreover, the placard under 2b imposes operational restrictions: IFR operation is prohibited, and use of the alternate static air source is prohibited. That may limit the aircraft’s utility until the later inspection is completed.

Duty to maintain documentation. While not explicit in the AD text, the duty to comply implies a duty to record the inspections and placard actions in the aircraft’s technical log or maintenance records. The AD references service bulletins; following those bulletins will involve making entries. The absence of a logbook endorsement showing compliance leaves the operator vulnerable to enforcement action.

Right to rely on a competent maintenance organisation. The operator is not required to personally perform the work; a licensed engineer may do so. However, the operator remains responsible for compliance.

Duty to source and follow the applicable service bulletin. The AD states that the procedures required are detailed in one of four named service bulletins. The operator or maintainer must obtain the correct bulletin for the model and perform the work accordingly.

Non‑compliance with an airworthiness directive is a serious matter under Australian aviation law. The AD is issued under the Civil Aviation Act 1988 and the Civil Aviation Regulations 1988 (CAR 1988). Specifically, CAR 1988 regulation 42 requires that an aircraft may not be operated unless it complies with all applicable ADs. Breach of that regulation is an offence. The penalty for operating an aircraft that does not comply with an AD can be significant. Under section 20A of the Civil Aviation Act 1988, an offence can attract a penalty of up to 200 penalty units for an individual (currently AUD 44,000 as of 2025, though the amount in 2009 would have been lower) and up to 1,000 penalty units for a body corporate. Additionally, CASA can apply to a court for an injunction to prevent operation of a non‑compliant aircraft.

CASA may take administrative enforcement action, such as issuing a show cause notice or imposing conditions on an air operator’s certificate or maintenance organisation approval. The AD itself does not set out enforcement provisions; it relies on the underlying regulatory framework.

Beyond direct legal penalties, non‑compliance has practical consequences. An aircraft that is not in compliance with the AD is unairworthy. Insurance policies may become void if the operator flies without complying with applicable ADs. Civil liability may arise if an incident occurs and the operator fails to comply; the operator could be found negligent per se.

The AD also imposes consequential duties: if an obstruction is found, Requirement 4 demands action before further flight. Failure to ground the aircraft after discovering an obstruction would be a separate and more serious breach. Flying with a known obstruction would evidence a conscious disregard for safety and could attract higher penalties or criminal charges under section 20 of the Civil Aviation Act (dangerous operation of an aircraft).

The AD gives no explicit right to an extension or deviation. However, CASA may issue an alternative means of compliance under CAR 1988 regulation 39 (or similar provision) if a person can demonstrate that the alternative provides an equivalent level of safety. That is a separate application process and is not mentioned in the AD itself.

The AD does not exist in isolation. It is issued under the Civil Aviation Act 1988 and the Civil Aviation Regulations 1988. The primary regulatory context is the requirement that an aircraft must not be operated unless it is airworthy and maintained in accordance with approved data. The AD forms part of that approved data.

The AD specifically cross‑references the United States Federal Aviation Administration (FAA) AD 2008-26-10 (Amendment 39-15776 dated 15 December 2008). This indicates that the Australian AD is substantially aligned with the FAA’s requirements for the same issue. Operators who have already complied with the FAA AD may still need to ensure that their actions meet the specific wording of the CASA AD, though the requirements appear essentially identical. The AD effectively harmonises Australian and US airworthiness requirements for this issue, which is common when an aircraft or component is certificated by both authorities.

The Background mentions an earlier FAA AD 2008-10-02. That earlier AD addressed the same placard obstruction issue but on other Cessna models (not the 336). This AD expands the coverage to the Cessna 336 and expands compliance actions after the FAA received reports of 15 aircraft not previously thought to have the problem. So this AD builds on a history of regulatory action that began earlier in 2008.

The AD also interacts with the applicable maintenance regulations. The inspections must be performed by a person authorised under the Civil Aviation Regulations, usually a licensed aircraft maintenance engineer (LAME). The work must be recorded in the aircraft’s maintenance release or logbook, and a certificate of release to service must be issued after each inspection. The placard installation and removal are themselves maintenance actions that require a LAME to certify.

Parts replacement (Requirement 5) interacts with the regulations governing the use of serviceable parts. Under CAR 1988 regulation 39F (or the later Part 42 of CASR), a part must be in an airworthy condition and have appropriate documentation. The AD adds an additional condition for P/N 2013142-18: it must have been inspected and found free from obstruction. This overrides the usual assumption that a new part from the manufacturer is acceptable without further inspection.

The AD may also interact with the operator’s own maintenance schedule. Many operators have approved maintenance programs (such as those under CAR 30 or Part 42) that allow for scheduled inspections. The AD imposes an unscheduled inspection that must be accommodated. The compliance times are designed to integrate with the existing hourly or calendar maintenance intervals (100 hours or 4 months), which is a sensible alignment.

This is the text of AD/CESSNA 336/15 as issued on 8 January 2009 and effective 16 January 2009. The source does not indicate any amendments to this specific AD within the document itself. There is no statement such as “revoked” or “supersedes” preceding ADs. However, the Background explains the regulatory history of the issue. The FAA issued AD 2008-10-02 in May 2008 addressing the same placard obstruction issue on other Cessna models. Later, the FAA issued AD 2008-26-10 (15 December 2008) which is the direct FAA counterpart to this CASA AD. This CASA AD appears to adopt the FAA’s requirements and apply them to Cessna 336 aircraft registered in Australia.

The AD references four Cessna service bulletins, each of which may have had earlier versions. The bulletins are dated October 2008, so they would have been issued in response to the earlier FAA AD 2008-10-02 or in anticipation of this AD. The text notes that the service bulletins provide the detailed procedures. Those bulletins may be revised in the future, but the AD does not incorporate by reference any specific revision , it names Revision 1 for some and original issue for others. This means that if a later revision is published, the AD’s reference to that specific version may become outdated. Operators should check the current status of the bulletins with CASA or Cessna to avoid using superseded procedures.

The AD does not contain a “history” clause. It is a standalone directive. For a complete amendment history, one would need to consult subsequent CASA records. It is possible that this AD has since been superseded by a later AD or incorporated into a routine airworthiness directive update. However, the source document is the original and only version provided.

In practice, ADs are living documents. CASA may issue a “Review of Airworthiness Directives” that rescinds old ADs whose actions have been completed or superseded by a permanent fix (e.g., a design change by Cessna). But based solely on the source, there is no amendment history to report beyond the initial issuance.

The source document does not mention any litigation, court cases, tribunal proceedings, or other legal disputes related to this AD or its subject matter. Given that ADs are technically prescriptive regulatory instruments, litigation is uncommon. Challenges to an AD would typically be brought in the Administrative Appeals Tribunal (AAT) or the Federal Court, arguing that the AD is beyond power, procedurally invalid, or unreasonable in some way. There is no indication that this AD has been challenged.

The underlying issue , obstruction of the alternate static air source selector valve port by a placard , was identified through operational reports to the FAA and CASA. The Background notes that 15 aeroplanes not previously affected were found to have the obstruction. This implies that there may have been incidents or reports that prompted the FAA to expand the scope of the earlier AD. However, no incidents are described, and no lawsuits are referenced.

It is possible that there have been insurance disputes or product liability claims arising from accidents involving erroneous static air indications, but the AD itself does not mention any case law. In the United States, the FAA issues ADs based on its own rulemaking authority; aviation product liability lawsuits may exist, but they are not referenced here.

From a compliance perspective, the absence of litigation history does not mean the AD is without teeth. CASA enforces ADs administratively, and non‑compliance would likely be dealt with by a civil penalty or a suspension of an air operator’s certificate, not by a court proceeding unless there is a criminal element.

Given the source does not provide any litigation details, we cannot construct a litigation history. The answer under this heading must be minimal but must exceed 200 words. We can explain why there is no litigation, discuss the nature of ADs as regulatory instruments, and note the theoretical grounds on which a challenge could be mounted (e.g., jurisdictional error, failure to follow the regulation‑making process). But we must stay grounded in the source and not invent. We can state: “No litigation history is evident from the source document. Airworthiness directives are typically not subject to frequent litigation; challenges are rare.” Then we can expand on the regulatory context, enforcement mechanisms, and alternative dispute resolution (CASA internal review). That should reach 200 words.

Several aspects of this AD are prone to misinterpretation or carry hidden compliance traps.

The temporary placard option for IFR aircraft (Requirement 2b) is not a permanent fix. An operator may hastily install the prohibitory placard before further flight as a quick solution, but they remain obliged to perform the physical inspection within 100 hours or four months. After that inspection, the placard must be removed before further flight. This means two maintenance events. If the operator fails to install the placard before further flight, they breach the AD immediately. If they install it but miss the later inspection deadline, they breach the AD. The compliance timeline for the inspection under Requirement 3 runs from the effective date, not from the date the placard is installed. That is a trap: an operator who installs the placard at, say, day 20 after the effective date still must complete the inspection by day 120 (four months from effective date) or at 100 hours TIS from the effective date, not from the placard installation date.

Confusion between the placard on the valve and the placard on the instrument panel. The AD uses the word “placard” in two different senses. The first is the part number identification placard attached to the valve body. The second is the new prohibitory placard installed on the instrument panel. Operators must carefully distinguish which placard is being discussed. Requirement 2b requires fabrication and installation of an instrument panel placard. Requirement 4 requires removal and discard of the part number placard from the valve body if obstructed. Requirement 3 requires removal of the instrument panel placards installed under 2b after the inspection. There is a risk of mixing up these instructions.

The inspection under Requirement 2a has a tight deadline: ten days. For an IFR‑equipped aeroplane that is not immediately available for maintenance, ten days may be insufficient. If the operator cannot arrange an inspection within ten days, the only lawful alternative is to immediately ground the aircraft and install the prohibitory placard under 2b before the next flight. However, the ten‑day clock and the “before further flight” clock run concurrently from the same effective date. This could cause confusion if the operator mistakenly thinks they have ten days to decide which path to take.

Replacement valve inspection requirement (Requirement 5) triggers a latent liability for stock. Parts stockists and repair stations holding P/N 2013142-18 valves must ensure that any valve sold after the ten‑day compliance date has been inspected and found free from obstruction. This creates a burden on the supply chain that might not be readily apparent to an operator purchasing a replacement valve from a third‑party source. The operator must verify that the valve has been inspected; if not, its installation would be non‑compliant. The AD does not specify who must perform the inspection; presumably it is the same procedure as for an installed valve, but the economic cost falls on the holder of the part.

No grace period for parts already installed. The AD applies to valves installed at any time since 1 January 1993. Even if a valve was installed before this AD was issued, it must be inspected. There is no exemption for valves that appear to be installed correctly. The Background makes clear that CASA cannot determine which valves have the problem without inspecting them. So every single affected aircraft must be inspected, regardless of whether the placard appears unobstructed on a cursory look.

The “IFR OPERATION IS PROHIBITED” placard may affect insurance and operational approvals. If the aircraft is prohibited from IFR operation, any flight plan or charter involving IFR would be illegal. The operator must notify any flight crew of the restriction. Failure to remove the placard after the inspection could inadvertently ground the aircraft for IFR operations, but the AD requires removal before further flight, so that should not be an issue if the engineer performs the removal. But if the placard is left because the engineer forgets, the aircraft could be unlawfully restricted.

Cross‑referencing the correct service bulletin may be tricky. The AD names four bulletins, but which one applies depends on whether the aircraft is a single‑engine or multi‑engine model. The Cessna 336 is a push‑pull twin with a unique configuration; the AD lists both single‑engine bulletins and a multi‑engine bulletin. An operator must ensure they use the correct bulletin; using the wrong one may lead to an incomplete inspection.

Compliance with AD/CESSNA 336/15 involves a series of steps that differ depending on the aircraft’s equipment and the operator’s choice. The general sequence is as follows.

Step 1: Determine applicability. Establish whether the aeroplane is a Cessna 336 and whether it was delivered between 1 January 1993 and 31 March 2008, or has had a P/N 2013142-18 valve installed as a replacement after 1 January 1993. Record the part numbers of any installed valves.

Step 2: Determine IFR capability. Check the aircraft’s equipment list to see if it is equipped for IFR. If not, proceed to the non‑IFR track. If yes, decide whether to inspect within ten days (Requirement 2a) or to install the placard immediately (Requirement 2b).

Step 3: Obtain the applicable service bulletin. For the Cessna 336, the relevant bulletin should be one of those listed: Cessna Multi‑engine Service Bulletin MEB08-6 dated 13 October 2008 is likely the correct one for this twin‑engine model. The bulletin contains the detailed inspection procedure. Download or purchase it from Cessna or CASA.

Step 4: For non‑IFR aircraft (Requirement 1). At the next scheduled maintenance that falls within 100 hours TIS or four months after the effective date (whichever first), the engineer must perform the inspection as per the service bulletin. That inspection includes verifying that the part number placard on the valve body is not obstructing the port. If it is obstructed, proceed to Step 6. If not, the action is complete; record it in the aircraft logbook.

Step 5a: For IFR aircraft choosing option 2a. Within ten days of the effective date (16 January 2009), the engineer must inspect the valve similarly. If obstructed, proceed to Step 6. If not obstructed, the action is complete; no placard is needed. Record the inspection.

Step 5b: For IFR aircraft choosing option 2b. Before the next flight after the effective date, the engineer must fabricate a placard meeting the letter‑size requirements (1/8 inch lettering) bearing the two statements: “IFR OPERATION IS PROHIBITED” and “USE OF THE ALTERNATE STATIC AIR SOURCE IS PROHIBITED.” Install it on the instrument panel in a location within the pilot’s clear view. Then, within the next 100 hours TIS or four months (whichever first), the engineer must perform the inspection as per the service bulletin. After that inspection, the placard must be removed before further flight. Record both the placard installation and the later inspection/removal.

Step 6: If an obstruction is found (Requirement 4). The engineer must remove the part number identifcation placard from the valve body, discard it, and ensure the port is unobstructed. This must be done before further flight. Record the action.

Step 7: For replacement valves (Requirement 5). As of ten days after the effective date, any P/N 2013142-18 valve to be installed must first be inspected for obstruction as per the service bulletin. Only valves found free from obstruction may be installed. Record the inspection and the condition.

Step 8: Document all actions. The aircraft logbook must contain entries referencing the AD number (AD/CESSNA 336/15), the total aircraft time or hours at the time of inspection, a statement that the valve was inspected and the placard (if any) was found free from obstruction (or removed), and the engineer’s certification.

Cost estimate. The labour time for the inspection is likely short (perhaps 15-30 minutes) plus the time to access the valve. The placard materials are negligible. The major cost is the opportunity cost of grounding the aircraft for the work, especially for the ten‑day inspection under option 2a. Operators should schedule maintenance to minimise downtime. For those with multiple aircraft, a single maintenance visit for the inspection may be the most cost‑effective approach. Choosing option 2b may increase total labour time due to two visits.

Record keeping. Keep copies of the service bulletin and the logbook entries. If a placard is removed, keep a record of which placard was removed and why. For replaced parts, ensure the part is traceable to an inspection record.