AD/CESSNA 206/62 Amdt 1 - Flexible Fuel Hose End Fittings

The central concept is an Airworthiness Directive (AD) - a legally binding directive issued under the Civil Aviation Act 1988 (Cth) and associated regulations that requires an aircraft owner or operator to perform a specified inspection, modification, or maintenance action on an aircraft type to correct an identified safety deficiency. Failure to comply with an AD renders the aircraft unairworthy, which is a breach of the airworthiness regulations and exposes the operator to enforcement action and potential grounding. This AD is a CASA AD that incorporates by reference a FAA AD (2007‑08‑03, Amendment 39‑15020, dated 5 April 2007) and a Cessna Service Bulletin (SB) - SB07‑71‑01, Revision 1. The SB is a manufacturer‑issued recommendation that becomes compulsory when adopted by an AD. The AD describes two groups of aircraft based on the presence of the Garmin G1000 system. The difference in hose listings between the groups reflects the fact that the G1000‑equipped models have a slightly different fuel system layout, so the AD tailors the inspection scope to each configuration. The AD also introduces the concept of torque putty or paint - a visual indicator of correct torque application that must be reapplied after the work is done. The appendix provides a sequential torque procedure: remove cowlings, clean old torque paint, loosen each fitting using a tool to restrain the opposite end to avoid twisting the hose, torque to the value specified in the SB, and then apply fresh torque paint. A critical sub‑concept is that if during the torque procedure any non‑hose end fitting rotates, the operator must stop, disconnect the joint, remove the rotated fitting, clean and visually examine it (and possibly replace it), then reinstall and repeat the torque steps. This recognises that rotating a fitting can damage seals or cause leaks, so the AD mandates a conservative response rather than simply re‑torquing. The compliance time is expressed in hours time‑in‑service (TIS) - a measure of actual flight hours rather than calendar time - which imposes operational urgency: the five‑hour window could be consumed in a single day of intensive flying. The background section of the AD notes that four reports of loose fuel lines on Cessna single‑engine models (including a 206H) led to in‑flight engine failures; the AD is thus a reactive measure to a pattern of field failures. From a free‑market perspective, the AD imposes a uniform mandatory design standard on private operators, eliminating the choice to accept a different risk profile or to defer the inspection until a convenient maintenance interval. The tight five‑hour compliance window also forces unscheduled downtime, which can disrupt charter, agricultural, or private flying operations and imposes opportunity costs on aircraft utilisation.

The primary duty‑bearers are the registered operators and owners of each Cessna Model 206H and T206H aeroplane falling within the listed serial number ranges. The AD does not specify whether the registered operator is a private individual, a flying school, a charter company, an agricultural operator, or a corporate flight department, but the legal responsibility to ensure compliance with the AD falls on the person in whose name the aircraft is registered under the Civil Aviation Regulations 1988 (CAR 47) or the Civil Aviation Safety Regulations 1998 (CASR 47). In practice, many operators contract maintenance to licensed aircraft maintenance engineers (LAMEs) or approved maintenance organisations (AMOs), but the AD does not transfer the legal obligation; the operator remains ultimately liable for ensuring the inspection is performed and the logbook endorsed. The specific aircraft affected are limited to production batches: for the 206H, serial numbers 20608231 through 20608285 (55 aircraft); for the T206H, serial numbers T20608515 through T20608662, T20608664 through T20608697, T20608699 through T20608714, and T20608717 (omitting T20608663, T20608698, T20608715, T20608716 - approximately 185 to 190 aircraft, depending on precise gaps). That totals roughly 240 to 250 aeroplanes - a small but significant subset of the Australian Cessna 206 fleet. The AD also implicitly affects maintenance organisations and licensed engineers who will be tasked with performing the inspection and any torque correction. They must have access to Cessna SB07‑71‑01, Revision 1, and the specified torque values, which may require purchasing the service bulletin if not already held. The appendix requires the use of a suitable tool to restrain fittings; this may involve specialised tools such as a crows‑foot spanner, torque wrench, and backup wrench, and the engineer must have the competence to apply the torque procedure without rotating non‑hose end fittings. The AD also affects parts suppliers if replacement fittings, seals, or hoses are needed as a result of the inspection - for example, if a non‑hose end fitting is found to have rotated and must be replaced. The insurers of affected aircraft may also take an interest: an aircraft that has been operated beyond the five‑hour TIS limit without compliance is technically unairworthy, which could void insurance coverage in the event of an incident. Finally, CASA’s airworthiness inspectors are affected to the extent they must verify compliance during routine surveillance or spot checks. The economic impact is concentrated on a small population of aircraft: each aircraft will incur direct labour (say 1-3 hours, including cowling removal and re‑installation), plus the cost of torque paint and any consumables. If any incorrect torque is found, the job may escalate to partial disassembly and possible part replacement. The five‑hour TIS window forces many operators to schedule an inspection immediately, which may cause cancellations or last‑minute hangar space bookings. There is no exemption for aircraft that have already been inspected under the original AD (effective September 2006) unless the earlier inspection met the expanded serial number coverage and used the correct revision of the service bulletin. Because Amendment 1 adds serial numbers, operators of those added aircraft now face a new obligation they did not have before.

The AD imposes two principal duties on the operator or maintainer. Duty 1: Inspection. Within 5 hours TIS after 25 April 2007, the operator must ensure that each of the specified hose end fittings on the aircraft is inspected for correct torque. The inspection must follow the combined instructions of the Cessna service bulletin and the appendix. The appendix gives a step‑by‑step procedure: remove cowlings, clean off old torque putty, loosen the hose end fitting while restraining the opposite end, then re‑torque to the SB‑specified value. Note that the appendix does not say “inspect and stop if correct”; it says “torque the hose end fitting to the proper torque”. This implies the AD expects the operator to break the torque joint and re‑torque every fitting, even if the existing torque appears correct. The cleaning of old torque putty and the requirement to reapply new putty after re‑torquing supports this reading: the AD intends a full re‑torque cycle, not merely a visual check. Duty 2: Correction. If during the inspection any incorrect torque value is found, the operator must establish the correct torque in accordance with the same instructions. The compliance times differ: the inspection must be completed within 5 hours TIS; the correction must be done “before further flight”. This means that if, during the inspection, a fitting is found to be loose or over‑torqued, the aircraft cannot fly again until the correct torque is applied, even if the 5‑hour TIS period has not expired. The operator also has a duty, under the broader regulatory framework, to record the AD compliance in the aircraft maintenance release (CAR 42) or logbook, and to retain evidence of compliance for future auditors. Operators have the right to perform the work themselves if they hold the appropriate aircraft maintenance engineer licence with type rating, or to contract an AMO to do it. They also have the right to challenge the AD’s applicability if they believe their aircraft is not within the listed serial numbers - for example, if the serial number falls outside the ranges or is one of the omitted numbers (T20608663, T20608698, etc.). There is no right to an extension of the 5‑hour TIS period under the AD itself; operators must apply to CASA for an alternative means of compliance or exemption under the Civil Aviation Act if they cannot comply in time. The AD does not impose a duty to replace any parts proactively; it only requires re‑torquing. However, the appendix introduces a further duty: if during the torque procedure any non‑hose end fitting rotates, the operator must stop, disconnect the joint, remove the rotated fitting, clean and visually examine it (and/or replace it), reinstall, and then repeat the torque procedure. This effectively creates a duty to perform a deeper inspection and possible replacement if the rotation occurs, which is a contingent duty triggered by the engineer’s actions. The AD does not specify a duty to test the engine run or carry out a fuel leak check after re‑torquing, though prudence and standard maintenance practices would likely require one. The absence of a test run requirement could be seen as a gap, since a loose or leaking fitting might not manifest until the fuel system is pressurised. The appendix also does not require the engineer to measure the torque of the non‑hose end fittings (the fitting that connects the hose assembly to the engine‑mounted component); it only addresses the hose end fitting itself. This means the duty is narrower than a full fuel system torque audit.

The AD is a legislative instrument made under delegation from CASA, which derives its powers from the Civil Aviation Act 1988 (Cth). A contravention of an Airworthiness Directive is a breach of the airworthiness requirements set out in the Civil Aviation Regulations 1988 (CAR 42) or the Civil Aviation Safety Regulations 1998 (CASR 42). The precise penalty depends on whether the operator is an individual or a body corporate. Under the Act, a breach of a safety regulation can attract civil penalties of up to 1,000 penalty units for an individual or 5,000 penalty units for a body corporate. As at 2007 a penalty unit was $110, meaning an individual could face a maximum civil penalty of $110,000 and a corporation up to $550,000. Additionally, CASA may impose administrative sanctions, including suspension or cancellation of the air operator’s certificate, the airworthiness certificate, or the aircraft’s registration. In serious cases, criminal prosecutions under the Crimes Act 1914 (Cth) could be pursued if a person recklessly endangers lives by operating an unairworthy aircraft. More commonly, enforcement takes the form of a direction to rectify, a notice of proposed action, or a caution. The AD itself does not create its own penalty clause; it relies on the framework of CAR/CASR. For an individual LAME who performs a non‑compliant inspection (e.g., fails to re‑torque all fittings, or fails to stop when a non‑hose end fitting rotates), CASA could take disciplinary action under Part 66 or Part 145 of CASR, which could involve suspension or revocation of the engineer’s licence. The AD does not prescribe specific immunity for good‑faith errors, so an engineer who misinterprets the appendix or uses the wrong torque value is exposed to liability. Practical enforcement is likely to be reactive: CASA airworthiness inspectors perform spot checks during aircraft inspections or after an incident. If an aircraft involved in a fuel‑related engine failure is found not to have complied with this AD, the operator would face significant evidentiary disadvantage if the failure could be linked to a loose fitting that the AD intended to prevent. The five‑hour TIS compliance window is extremely tight and may catch operators off guard; any operator who inadvertently exceeds the window and continues to operate the aircraft is in technical breach even if no incident occurs. Given the relatively small number of affected aircraft and the one‑time nature of the AD, CASA may have limited resources to monitor compliance. However, the legal risk remains significant, particularly because insurance policies typically exclude liability arising from non‑compliance with an AD. Therefore, the penalty for non‑compliance is not just the statutory fine but the potential loss of insurance cover for any fuel‑system incident, which could expose the operator to full tort liability for property damage, bodily injury, or death. This AD thus creates strong economic incentives to comply promptly, even though the probability of a CASA audit is low. From a free‑market perspective, the AD imposes a mandatory cost that cannot be avoided by private risk‑management choices; the operator cannot elect to accept a higher risk and bypass the inspection. The penalty structure provides a powerful lever for the regulator, but it also means that a financially constrained operator might be tempted to defer compliance and risk enforcement.

This AD is a CASA instrument that incorporates by reference two external documents: the FAA AD 2007‑08‑03 (Amendment 39‑15020) and Cessna Service Bulletin SB07‑71‑01, Revision 1. The FAA AD is itself an airworthiness directive issued by the US Federal Aviation Administration, which would apply to US‑registered aircraft. However, CASA has chosen to issue its own AD rather than simply adopt the FAA AD automatically. This means that for Australian‑registered aircraft, the CASA AD is the legally binding instrument; the FAA AD is referenced only as background. The AD says “FAA AD 2007‑08‑03 Amendment 39‑15020 dated 5 April 2007 refers” and notes that the FAA AD supersedes an earlier FAA AD 2006‑17‑04. This suggests that CASA has aligned its AD with the latest FAA requirements but has used its own numbering and applicability. The interaction with the Civil Aviation Regulations 1988 (CARs) and Civil Aviation Safety Regulations 1998 (CASRs) is fundamental: compliance with an AD is a condition of maintaining the aircraft’s airworthiness certificate. Under CASR 42, an aircraft must be maintained in accordance with “the instructions issued by the manufacturer” and “any airworthiness directive issued by CASA”. Therefore, this AD sits on top of the general airworthiness obligations. The AD also interacts with the manufacturer’s service documents: although the SB is voluntary when issued by Cessna, its adoption by the AD makes it mandatory. Any later FAA‑approved revision of the SB is automatically accepted by the AD (the text says “or later FAA approved revisions”), so operators do not need a new AD each time the SB is updated. This is a sensible regulatory approach that avoids repetitive amendments. The AD does not explicitly exempt aircraft that hold a special flight permit (e.g., for ferry flights), so a ferry permit might still require compliance if the aircraft is operated within the 5‑hour TIS window. There may be an interaction with state or territory work health and safety laws in that an employer who requires a pilot to fly a non‑compliant aircraft would face WHS prosecution risk. Additionally, the AD interacts with the Competition and Consumer Act 2010 (Cth) to the extent that an operator who markets a compliant aircraft for sale could be liable for misleading conduct if the AD has not been complied with. The AD does not override or replace the requirements of the manufacturer’s maintenance manual; it supplements them. In the event of a conflict between the AD and the maintenance manual (e.g., if the manual suggests a different torque procedure), the AD prevails because it is a mandatory regulatory instrument. The appendix gives specific instructions on what to do if a non‑hose end fitting rotates: stop, disconnect, remove, clean, examine, replace if necessary, and re‑torque. That procedure may not be in the maintenance manual, but it must be followed. The AD also interacts with the International Civil Aviation Organization (ICAO) standards, as Australia is a signatory to the Chicago Convention, but this is a background consideration. For operations conducted under a foreign air operator certificate that operates into Australia, the operator must comply with the requirements of the state of registry; if the aircraft is Australian‑registered, the CASA AD applies regardless of where it operates. In summary, this AD is a mandatory overlay on a complex web of civil aviation safety regulations and imposes its own specific, time‑sensitive procedure that cannot be modified by contract or manual.

AD/CESSNA 206/62 was originally issued with an effective date of 4 September 2006. That original AD applied to a narrower set of serial numbers and likely relied on Cessna SB07‑71‑01 without the detailed appendix. The amendment under review here is Amdt 1, signed by David Villiers on 19 April 2007 and effective 25 April 2007. The amendment makes two substantive changes. First, it expands the applicability by adding additional serial numbers to the existing list. The original AD may have covered only an initial production run; the amendment captures later production aircraft that were delivered after the original AD’s effective date. Specifically, the new serial numbers include T20608664 through T20608697, T20608699 through T20608714, and T20608717 - a block of about 50 to 60 additional aeroplanes. Second, the amendment adds an appendix to the AD that provides detailed inspection instructions. The original AD presumably cross‑referenced the Cessna SB without specifying the step‑by‑step torque procedure; the appendix now acts as a stand‑alone guide that clarifies exactly what the engineer must do, including the critical requirement to stop if a non‑hose end fitting rotates and to replace it. The appendix is likely a response to confusion or inconsistent compliance identified during the initial enforcement period. The amendment also implicitly supersedes the original AD: the compliance date for the expanded applicability is the new effective date (25 April 2007), but aircraft that were already subject to the original AD are not given a fresh time limit; the 5‑hour TIS window is now measured from 25 April 2007, so those aircraft effectively get another 5 hours TIS to repeat the inspection if they already did it under the original AD. This could be seen as a regulatory inefficiency - an aircraft that complied perfectly under the original AD must now re‑inspect within 5 TIS of the new date, incurring additional cost. However, the amendment may be justified by the new appendix, which provides a more rigorous procedure. The AD also notes that it incorporates “FAA AD 2007‑08‑03 Amendment 39‑15020 dated 5 April 2007” and that this FAA AD supersedes FAA AD 2006‑17‑04. That cross‑date alignment suggests CASA intended to harmonise with the latest FAA requirements. The original AD had no stated amendment number; this is the first amendment (Amdt 1). No further amendments are indicated in the source document. The AD form shows “Amdt 1” in the header and the original effective date of 4 September 2006 is mentioned in a separate line. For practitioners, the history matters because any aircraft that was not originally subject to the AD now becomes subject, and any aircraft already subject must confirm that the earlier compliance action matched the revised SB revision (Rev 1) and the new appendix. If an operator in 2006 complied using the original SB (perhaps Rev 0 or a version without the appendix), that compliance is likely no longer sufficient; the operator must perform the inspection again using the updated instructions. The amendment thus imposes retrospective re‑inspection on a fleet that may have already expended resources on the original AD.

The source text for this AD refers to no litigation. No cases are mentioned in the AD itself, nor is there any reference to a court challenge to the validity of the AD or to any enforcement proceedings that might have tested its interpretation. This is typical for a routine airworthiness directive that has a narrow scope and a short compliance window. The AD is a legislative instrument that could theoretically be challenged under the Administrative Decisions (Judicial Review) Act 1977 (Cth) or under the Constitution by a party claiming that it is ultra vires the Civil Aviation Act, but no such challenge appears to have been recorded. The background narrative of four reports of loose fuel lines suggests that CASA (and the FAA) acted on incident data rather than on a full analysis of causation; a litigant might argue that the AD was disproportionate if the loose fittings were attributable to a contractor error rather than a design flaw, but the AD pre‑empts such an argument by making the corrective action relatively cheap and non‑invasive (re‑torquing). In the absence of litigation, the AD has not been judicially interpreted. This means that the meaning of phrases like “any incorrect torque values” and “while using a suitable tool to restrain the other end fitting” has not been tested in court. For compliance professionals, that introduces some ambiguity: what constitutes a “suitable tool”? Is it defined by the manufacturer, or is it left to the engineer’s discretion? If a dispute arose after an engine failure, a court might have to determine whether the engineer exercised due care. Similarly, the requirement to “establish the correct torque values” might be read as a duty to consult the service bulletin and apply the specific value, not to use a generic torque for that size of fitting. Without litigation, the boundaries of compliance remain untested, which creates a degree of legal risk for operators who may deviate from the appendix’s wording, e.g., by using an alternative procedure they believe is equivalent. The absence of litigation also means there is no judicial commentary on the proper method of recording compliance. Since the AD does not specify the logbook entry format, a standard maintenance entry must suffice, but that entry could be scrutinised if an incident occurs. The overall litigation history is a blank slate, which is both a comfort (no adverse precedent) and a risk (no guidance on disputed terms). Operators should err on the side of conservative compliance, given the high economic stakes of a post‑accident investigation.

There are several aspects of this AD that could trip up even experienced operators and engineers. First, the compliance time is extremely tight: within 5 hours TIS of the effective date. For an aircraft that flies a lot (e.g., a charter or agricultural operator), 5 hours could be consumed in a single day, so the inspection must be done before the aircraft flies after 25 April 2007, not five hours into operations. An operator who delays even one flight risks non‑compliance. Second, the AD’s appendix does not say “inspect for correct torque and only re‑torque if necessary”. It says “using a suitable tool loosen the hose end fitting … torque the hose end fitting to the proper torque”. The step effectively mandates re‑torquing every listed fitting, not just checking. An engineer who merely checks torque without loosening and re‑torquing is not following the appendix. However, the requirement text (the AD body) says “Inspect the two end fittings … using the instructions of Cessna SB … and the procedures given in the appendix” and then “If any incorrect torque values are found … establish the correct torque values”. The body appear to allow an inspect‑only approach: if the torque is already correct, no further action is needed. But the appendix’s step 3 (“loosen the hose end fitting”) and step 4 (“torque … to the proper torque”) are written as a universal procedure, not conditional on finding incorrect torque. This creates a direct conflict between the body and the appendix. A court or CASA would likely hold that the appendix governs the inspection method, meaning every joint must be broken and re‑torqued. This is a gotcha: many operators might rely on the body’s conditional language and simply torque‑check with a wrench, but that would be non‑compliant. Third, the AD does not require a run‑up or fuel leak test after re‑torquing. An engineer who re‑torques a fitting may disturb the seal, yet the AD does not require verifying the absence of leaks. A prudent engineer will perform a leak check, but the AD does not mandate it, and failure to do so could lead to a fuel drip that goes unnoticed until engine start. Fourth, the appendix’s requirement to stop if a non‑hose end fitting rotates is absolute: “stop the torque procedure. Totally disconnect the hose end joint and remove any fitting that has rotated.” That means the engineer cannot simply tighten it back and proceed; they must dismantle, clean, inspect, and possibly replace the fitting. This imposes significant additional labour and potential parts sourcing for a problem that might be minor. Fifth, the AD references “any later FAA approved revisions” of the SB. The operator must ensure they use the latest revision, not the one in their maintenance data. If the SB was updated after 16 March 2007, the operator must obtain the latest revision, which may have different torque values or procedures. Sixth, the serial number applicability has gaps: for example, T20608663, T20608698, T20608715, and T20608716 are omitted. Operators of those serial numbers might assume they are not affected, but if there is a typo in the AD or if the actual serial falls within a continuous range, they could be caught. It is essential to check the actual serial number against the list exactly. Seventh, the AD does not specify where in the engine compartment these hoses are located; the engineer must use diagrams from the SB. An engineer unfamiliar with the Cessna 206 fuel system might miss a hose listed under Group 2 if they only reference Group 1. Eighth, the effective date of 25 April 2007 means that if an aircraft was already in the maintenance hangar on that date, the 5‑hour counter starts ticking, so the aircraft cannot be returned to service without the AD being done, even if it was already undergoing other work. Finally, the AD does not provide a means to delegate the compliance check to a pilot or a non‑engineering person; only a properly authorised engineer may perform the work under the maintenance regulations. An owner who thinks they can do it themselves without a licence is mistaken.

Compliance with AD/CESSNA 206/62 Amdt 1 requires a systematic approach that carefully follows the AD text, the referenced service bulletin, and the appendix. The steps are as follows.

Step 1: Verify applicability. Obtain the aircraft’s serial number (found on the data plate) and check it against the list: Model 206H from 20608231 through 20608285, Model T206H from T20608515 through T20608662, then T20608664-T20608697, T20608699-T20608714, and T20608717. If the serial number is not listed (or is one of the omitted numbers), the AD does not apply, and no further action is needed on this basis alone. However, the aircraft may still be subject to the FAA AD if it is US‑registered or operates under a foreign certificate.

Step 2: Determine the group. Check whether the aircraft is equipped with the Garmin G1000 system. If it is, use the Group 2 hose list; if not, use Group 1. Note that turbo‑charged models (T206H is turbocharged) have additional hoses listed under Group 1 (items iii, iv, vi, vii). For Group 2, turbo‑charged models are also listed but the hose list differs; compare carefully.

Step 3: Obtain the required documents. Secure a copy of Cessna Service Bulletin SB07‑71‑01, Revision 1, dated 16 March 2007 (or any later FAA‑approved revision). The service bulletin will contain the exact torque values for each fitting. Also have the AD appendix printed for reference. If the operator does not hold the SB, they must purchase it from Cessna or an authorised distributor.

Step 4: Schedule the inspection within 5 hours TIS after 25 April 2007. For an aircraft that has not flown since that date, the inspection must be performed before next flight or at the next maintenance opportunity, but within 5 flight hours. If the aircraft has already flown more than 5 hours since the effective date, it is technically out of compliance and must be inspected immediately, with no further flight until the inspection is completed and any corrections made.

Step 5: Perform the inspection/torque procedure as per the appendix. The engineer must:

• Remove the upper and side engine cowlings.
• Remove all signs of old torque putty or paint from each hose end fitting joint to be worked.
• For each specified hose, use a suitable tool to loosen the hose end fitting while using another tool to restrain the opposite end fitting (the non‑hose end) to stop the hose from twisting.
• Clean the fitting threads and mating surfaces as needed (the appendix does not mandate cleaning, but it is good practice).
• Apply the correct torque value from the SB to the hose end fitting, again restraining the non‑hose end to prevent rotation.
• After achieving the correct torque, apply fresh torque putty or paint to the joint as a visual indicator.
• If, during any of these steps, the non‑hose end fitting rotates, stop immediately, disconnect the joint entirely, remove the rotated fitting, clean and visually examine it (and/or replace it if damaged), reinstall it, and then repeat the loosening and re‑torquing steps from step 3 of the appendix.

Step 6: Inspect and correct any incorrect torque. The AD’s body says to “inspect” and then “if any incorrect torque values are found, establish the correct torque”. Given the appendix’s mandatory re‑torque language, it is safest to treat every fitting as requiring re‑torque even if the torque is initially within limits. The prudent approach is to break every joint and re‑torque.

Step 7: Reinstall cowlings after all hoses have been re‑torqued and torque paint applied.

Step 8: Perform a leak check. Although not explicitly required by the AD, a fuel system pressure test and visual leak check is essential to ensure no seal damage occurred during re‑torquing. Run the engine and inspect for drips or stains after shut‑down.

Step 9: Record compliance. Make an entry in the aircraft maintenance release (or logbook) stating that AD/CESSNA 206/62 Amdt 1 has been complied with, the date, hours TIS at compliance, the SB revision used, and a statement that all specified hose end fittings were inspected and torqued as required. If a rotated fitting was found and replaced, describe the part number and remedial action. The entry must be made and signed by a person authorised under CAR 42 or CASR Part 42.

Step 10: File copies of the SB, the AD, and the compliance entry in the aircraft records. These must be retained for at least as long as the aircraft is in service. Non‑compliance can be detected years later during a sale inspection, and without proper records the aircraft may be un‑saleable or require repeat compliance.

Step 11: Consider future SB revisions. The AD accepts “later FAA approved revisions” of the SB. If Cessna issues Rev 2, the operator must decide whether it changes the torque values or adds new hoses. If it does, the AD automatically requires following the new revision, but only for aircraft that have not yet complied with the one‑time AD. For aircraft that have already complied, no further action is needed unless the AD is amended again. However, if the new revision contains a different torque value, the operator who complied using Rev 1 should not re‑torque, but a future purchaser or maintainer should check. The ambiguity here is that the AD does not state whether compliance with an earlier revision remains valid if a later revision is issued; the safest approach is to use the latest revision at the time the work is performed.

Step 12: For aircraft outside the serial number range but still fitted with the same hoses, there is no legal requirement under this AD, but the operator may voluntarily adopt the inspection as good practice, given the background of in‑flight failures. That is a commercial decision, not a legal one.