AD/LYC/116 - ECi Connecting Rods

The AD introduces several specialised concepts that are critical for understanding the scope and obligations:

Time-in-service (TIS): This refers to the total accumulated hours the connecting rod has been in operation since it was first installed. The AD uses TIS as the primary trigger for differentiating compliance deadlines - rods with 2,000 or more hours TIS must be replaced before further flight (effectively grounding the aircraft), while rods with fewer than that threshold may be replaced at the next overhaul or accessibility, but capped at 2,000 hours TIS. Note that the TIS clock runs on the connecting rod itself, not the engine or airframe. This means if the rod was replaced at some point, its TIS starts from installation of that rod, not from engine manufacture.

Connecting rod accessibility: The AD defines this as "any maintenance action in which a cylinder assembly is removed for maintenance." This is a crucial concept because it provides an intermediate compliance event for rods with fewer than 2,000 hours TIS. An operator who must replace a cylinder for any reason (e.g. cylinder replacement, cylinder head work, piston replacement) must also replace the connecting rod at that time, even if the rod's TIS is still well below 2,000 hours. This provision effectively accelerates compliance for engines that undergo major cylinder maintenance before the rod reaches its TIS limit.

Lot number and serial number: The affected rods are identified by a specific lot number (54) and serial numbers 6 and below. The AD explains that "54 is the lot number and 7 is the serial number of the ECi connecting rod." The critical cut-off is lot 54, serial 7 and above are not affected, while lot 54, serial 6 and below are affected. This is an extraordinarily narrow identification - only the first six rods from lot 54 are captured. The AD also references "forging P/N AEL11488" which is raised lettering on the web of the beam between the big and small ends of the connecting rod, providing a physical identification check beyond just the part number.

Parts Manufacturer Approval (PMA): The background section notes that Airmotive Engineering Corp (Division of ECi) holds the PMA for the affected parts. PMA is a US FAA approval that allows a manufacturer to produce and sell replacement parts for type-certificated aircraft engines. In the Australian context, the AD treats these PMA parts as subject to the same airworthiness requirements as OEM parts. This concept is relevant because the AD does not ban all ECi connecting rods - only those with lot 54, serial 6 and below, which are presumably from a specific production run that had manufacturing quality issues.

Airworthiness Directive (AD): This is the regulatory instrument itself. Under the Civil Aviation Act 1988 and Civil Aviation Safety Regulations 1998 (CASR Part 39), an AD is a legally enforceable notice requiring inspection, modification, or replacement of aircraft components to address an unsafe condition. Non-compliance renders the aircraft unairworthy and subjects the operator to enforcement action. The AD is issued by a delegate of CASA - in this case James Coyne, a Delegate of CASA. The AD takes precedence over any maintenance manuals or manufacturer's instructions if they conflict with the directive's requirements.

The AD affects a narrow but specific population of engine owners, operators, maintenance organisations, and parts vendors. The primary subjects are:

Engine owners and operators of aircraft with Lycoming 360 and 540 series reciprocating engines that have been overhauled or repaired since new. The AD explicitly exempts engines that have never been overhauled or repaired - these engines, even if equipped with ECi connecting rods P/N AEL11750 from the factory, do not require any action. This distinction creates a peculiar asymmetry: a pristine original engine is safe, but an engine that received the same rod as a replacement part during an overhaul is subject to mandatory replacement. This likely reflects that the defective rods were only sold as replacement/spare parts through ECi's PMA, not installed during original manufacture by Lycoming.

Maintenance facilities and repair stations that performed overhauls or repairs on Lycoming 360/540 series engines between January 2002 and January 2004 are indirectly affected because their work may have introduced the affected rods. Such facilities may be on notice to assist owners in identifying whether ECi rods were installed. However, the AD does not impose obligations on the past repair facility - the duty falls on the current operator.

Used engine and parts market participants: The prohibition on installing any ECi rod with lot 54/serial 6 or lower into any engine after the effective date means that dealers, brokers, and rebuilders cannot buy or sell these specific rods for installation. This effectively destroys the residual value of those parts and creates a potential liability for anyone who sold them previously without disclosing the AD risk.

Specific engine models: The AD lists an exhaustive table of affected engine models covering a wide range of variants within the Lycoming 360 and 540 series, including carbureted (O-), fuel injected (IO-), geared (GIO-), supercharged (TIO-), and aerobatic (AEIO-) versions. The full list includes dozens of suffixes. Notably, some engine types that might be expected (e.g. certain LIO- or HIO- models) are included, but the AD does not include the 320 series engines - only 360 and 540. Owners must check if their specific engine model appears on the list.

Private aircraft owners and commercial operators: Small general aviation operators (including owner-pilots flying light aircraft such as Cessna 172s, Piper Arrows, Beechcraft Bonanzas, or experimental amateur-built aircraft that use these Lycoming engines) are directly affected. Commercial operators (charter, flight training, aerial work) face additional operational disruption because compliance deadlines are short: rods with 2,000+ hours TIS must be replaced before further flight, potentially grounding an aircraft.

The compliance burden falls disproportionately on owners whose engines have accumulated high time since the last overhaul, especially those nearing or exceeding 2,000 hours TIS on the connecting rod. For those with fewer than 2,000 hours TIS, the directive provides some flexibility but still requires action before the rod reaches 2,000 hours, at the next overhaul, or whenever the cylinder is removed - whichever comes first. This uncertainty imposes a monitoring obligation on owners to track rod TIS accurately.

The AD establishes clear, mandatory duties on the person responsible for the aircraft's airworthiness - typically the registered operator or the pilot in command. The duties are set out in the "Requirement" column and are binding under the Civil Aviation Act.

Duty to inspect records: Before further flight after 31 May 2006, the operator must inspect the maintenance records and engine logbook to determine whether any overhaul or repair facility used ECi connecting rods P/N AEL11750. This is a desk exercise unless the engine logbook is missing records, in which case the operator may need to physically inspect the connecting rod to identify it by forging number and serial number. The AD does not prescribe a method of inspection if records are incomplete, creating a practical difficulty.

Duty to replace (conditional): If the connecting rod meets the criteria (ECi P/N AEL11750, forging P/N AEL11488, serial 54/6 or lower), the operator must replace it:

• Before further flight if the rod has 2,000 or more hours TIS.
• At the next engine overhaul, or at next accessibility (if cylinder is removed for maintenance), but in any case before the rod reaches 2,000 hours TIS.

Note that "no later than 2,000 hours TIS" is a hard deadline. An operator who delays overhaul past 2,000 hours while the rod is untouched would be in violation because the rod would exceed 2,000 hours TIS without being replaced. This implicitly requires the operator to schedule an overhaul or accessibility before that threshold.

Duty not to install: After the effective date, no person may install an affected ECi rod into any engine. This creates a permanent ban on installation of those specific parts, effectively making them scrap. This duty applies to all persons, not just operators - including maintenance organisations, parts suppliers, and private individuals.

Rights: The AD does not explicitly grant rights, but certain rights are implied by the structure of compliance:

• The right to use alternative connecting rods that are not affected by the AD (i.e., with lot 55 or higher, or different part numbers).
• The right to defer compliance for rods with fewer than 2,000 hours TIS until the next scheduled maintenance event, provided the 2,000-hour cap is not exceeded.
• The right to apply for an alternative means of compliance (AMOC) under CASR Part 39 - though the AD does not mention this, it is a standard provision in Australian AD practice. The AD references the FAA AD, and operators who have an FAA-approved AMOC may be able to use it in Australia if CASA determines it to be compatible.

The AD also implicitly acknowledges the operator's right to keep the aircraft grounded until the rod is replaced - that is a practical option, though an expensive one. There is no right to continue flying with an affected rod that has reached 2,000 hours TIS; the AD mandates replacement before further flight at that point.

One subtlety: the AD says "If your engine has not been overhauled or had any repair since new, no further action is required by this AD." This implies that the original engine with ECi rods from the factory is fine. But if that original engine was produced between January 2002 and January 2004 with ECi rods (which would be unusual given the rods were sold as PMA parts), the operator would still be exempt. The duty only triggers if the engine has been overhauled or repaired. This creates an incentive for operators of original engines to avoid any repair that might disturb the connecting rods, because after a repair, the AD would then apply.

The AD itself does not specify monetary penalties or imprisonment terms - those are set out in the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998 (CASR). However, the enforcement framework is well understood in Australian aviation law.

Criminal liability: Operating an aircraft in contravention of an airworthiness directive is an offence under section 20A of the Civil Aviation Act 1988. The maximum penalty for an individual is 50 penalty units (currently $11,000 as of 2024 when one penalty unit is $222). For a corporation, the penalty can be up to $55,000. Additionally, if the contravention results in a safety incident, the operator could face more serious charges under the Criminal Code or the Transport Safety Investigation Act 2003.

Civil liability: Non-compliance with an AD can result in cancellation or suspension of an Airworthiness Certificate, which effectively grounds the aircraft. CASA can issue a verbal or written directive to the operator to ground the aircraft until compliance is achieved. Continued operation without compliance can lead to enforcement action including seizure of the aircraft (section 30 of the Civil Aviation Act).

Pilot licensing consequences: A pilot who operates an aircraft known to be non-compliant with an AD may face action against their pilot licence under regulation 202 of CASR. The pilot has a duty to ensure the aircraft is airworthy before flight - if they have knowledge of the AD and the affected rod, they could be held personally liable.

Enforcement by CASA: The AD is a mandatory instrument. CASA delegates can issue directions under regulation 14A of the Civil Aviation Regulations 1988. Failure to comply with a direction can lead to higher penalties. CASA also coordinates with the Australian Transport Safety Bureau (ATSB) if an accident or incident occurs involving a connecting rod failure. The AD's background notes that its intent is to prevent fatigue failure and uncommanded engine shutdown - such a failure could be catastrophic.

Practical enforcement difficulties: The AD requires inspection of maintenance records; if an operator fails to perform that inspection and simply continues flying, the breach may not be detected unless CASA conducts an audit or until an incident occurs. The AD does not require reporting of compliance to CASA - the obligation is self-enforcing. This places a premium on good recordkeeping and operator integrity. Maintenance organisations may also be required to report compliance within their internal systems, but there is no central database tracked by CASA for this specific AD.

Interaction with insurance: Non-compliance with an AD could void hull and liability insurance policies. Most aviation insurance policies require the aircraft to be maintained in compliance with all applicable ADs. An accident caused by a connecting rod failure while the AD was not complied with could result in the insurer denying coverage, leaving the operator exposed to significant financial loss.

Consequences for maintenance organisations: A repair facility that installs an affected ECi connecting rod after the effective date would be in breach of the AD. This could result in loss of CASA-approved maintenance organisation certification (such as Part 145 approval) and potentially civil penalties.

Regulatory guidance: The AD references FAA AD 2006-10-21, indicating that the US FAA took a parallel approach. In Australia, CASA delegates have enforcement discretion, but given the safety justification, compliance is expected to be strictly enforced.

This Airworthiness Directive operates within a broader legal framework of aviation safety regulation in Australia and interacts with both domestic and international law.

Civil Aviation Safety Regulations 1998 - Part 39: CASR Part 39 is the specific regulation under which this AD is issued. Part 39 sets out the legal effect of ADs, the process for issuing them, and the obligations for operators. The AD is one of hundreds issued by CASA under this part. Operationally, Part 39 requires that each AD be recorded in the aircraft's maintenance records and that compliance be attested by the person performing the work. The AD does not repeat those general requirements, so operators must comply with the broader record-keeping obligations of Part 39.

Civil Aviation Regulations 1988 - Regulation 42ZF: Under the older Civil Aviation Regulations (CAR), regulation 42ZF required that airworthiness directives be complied with. However, the modern CASR regime has superseded many CAR provisions. Operators must understand which set of regulations applies to their aircraft type (e.g. experimental aircraft have different requirements). This AD refers to "CASA" powers under the Act, indicating it is made under the current legislative framework.

FAA AD 2006-10-21: The AD notes that it refers to FAA Airworthiness Directive 2006-10-21 (Amdt 39-14604 dated 12 May 2006). This cross-reference is significant because it means CASA harmonised its directive with the US airworthiness authority. For imported aircraft (especially those from the United States), the FAA AD would also apply if the aircraft is on the US register. In Australia, CASA's AD takes precedence for Australian-registered aircraft. However, if an aircraft operates under a foreign registration (e.g., N-registered aircraft in Australia), the operator must comply with both the FAA AD and any applicable CASA requirements - though typically CASA recognises FAA AD compliance. The AD does not specify whether compliance with the FAA AD is sufficient to meet CASA requirements, but given the nearly identical language, it likely is.

Airworthiness certificates and maintenance regulations: The AD interacts with the requirements for continued airworthiness. Under CASR Part 42 (continuing airworthiness) and Part 43 (maintenance), the operator must ensure that any mandatory directive is complied with. Failure to do so renders the airworthiness certificate invalid. The AD also affects the return-to-service procedure: after a rod replacement, a licensed aircraft maintenance engineer (LAME) must endorse the logbook and file the relevant form.

Type certificate data sheets: The AD does not modify or supersede the Lycoming engine type certificate. The affected engines still have their type certificate, but this AD imposes additional inspection requirements that are not in the original type design. For experimental aircraft that use Lycoming engines, the AD still applies because the aircraft is operating under a Special Certificate of Airworthiness that requires compliance with ADs unless specifically exempted.

State and territory laws: No interaction directly, but workplace health and safety laws in each jurisdiction require maintenance organisations to ensure safe work practices during rod replacement. The process of removing cylinders and replacing connecting rods involves standard maintenance procedures that must also comply with occupational health and safety regulations.

International agreements: Australia is a signatory to the Convention on International Civil Aviation (Chicago Convention). Under Annex 8 (Airworthiness of Aircraft), CASA is required to ensure that aircraft on its register meet airworthiness standards. This AD helps Australia meet its international obligations. There is no direct provision for extraterritorial application - the AD applies to Australian-registered aircraft wherever they are in the world.

Product liability and consumer law: The AD does not modify product liability laws. If an ECi connecting rod fails due to the condition identified (excessive variation in circularity of the journal bores), the manufacturer may be liable for damages under tort law. The AD's issuance could be used as evidence of a known defect in product liability litigation. Interestingly, the AD does not require ECi to take any action - the burden is entirely on aircraft owners.

The source text does not contain any amendment history. This compiled version of AD/LYC/116 is dated 24 May 2006, with a stated effective date of 31 May 2006. The AD does not reference any earlier versions, amendments, or superseded directives for this specific subject matter.

However, we can infer from the document structure that this is likely the original issuance of the AD. The reference to FAA AD 2006-10-21 indicates that CASA acted after the FAA issued its directive on 12 May 2006. Given the urgent safety nature (connecting rod failure risk), it is unlikely that there were earlier versions.

In the broader context of CASA AD practice, ADs can be amended or superseded by later directives. AD/LYC/116 is one of a series of Lycoming engine ADs bearing the prefix "LYC". There are other ADs in the LYC series addressing different issues (e.g., crankshaft cracks, cylinder hold-down nuts, etc.). This particular AD has not been supplemented by any later amendments in the available text.

It is possible that CASA later issued a superseding AD that revised the compliance deadlines or added new serial numbers. A diligent reader should check the current status of AD/LYC/116 on the CASA website to see if it remains current or has been withdrawn, amended, or superseded. The typical lifecycle of an AD is that it remains in effect until the unsafe condition is no longer present (e.g., all affected parts are removed) or a design change makes it obsolete.

The AD does not include a sunset clause or expiry date. It is intended to remain in effect indefinitely until withdrawn by CASA. If the connecting rod issue was limited to a specific production batch, once all rods of lot 54/6 and below have been replaced, the AD becomes effectively dormant but remains legally in force for any later-discovered engines.

For completeness, the AD's format (table with Applicability, Requirement, Compliance) is standard for CASA ADs issued in 2006. Since then, CASA has moved to a digital system and different formatting, but the legal effect is the same. The absence of amendment history in the source means that any analysis of later developments must be obtained from updated CASA records.

The source text does not mention any litigation related to this AD. No court decisions, administrative appeals, or tribunal rulings are referenced. The AD was issued in May 2006, and it is possible that no legal challenges were filed against it.

Airworthiness directives are rarely litigated in Australia because they fall within the broad regulatory discretion of CASA as the aviation safety regulator. The Civil Aviation Act provides CASA with the power to issue ADs without prior notice or consultation if safety is at imminent risk. The AD in question was likely issued under such expedited procedures. Judicial review is possible under the Administrative Decisions (Judicial Review) Act 1977, but applicants must show that the decision was unreasonable, procedurally unfair, or beyond power.

Given the technical nature and the safety justification (preventing connecting rod fatigue failure), a challenge would be difficult to sustain. The cost of litigation - likely exceeding the cost of compliance for most operators - also discourages challenges.

There is no reported case law of any party challenging this specific AD. A search of Australian legal databases would likely yield no results. The AD has been on the books for 18 years with no recorded judicial consideration. This does not mean there have been no legal disputes - there may have been disputes over compliance, insurance coverage, or liability after an incident, but those would be private law matters not involving the validity of the AD.

One potential area of litigation is product liability: if a connecting rod failed and caused an accident, the injured party might sue Lycoming, ECi, or the maintenance facility. The AD would be relevant evidence that the defect was known and that the part should have been replaced. However, that is not litigation against the AD itself.

In summary, the litigation history is effectively nil. The AD has been quietly complied with by the affected fleet. The absence of litigation may indicate that the directive was narrowly targeted, clearly justified, and compliance was achievable, so no party found it worthwhile to challenge.

The AD contains several traps that could catch an unwary operator or maintenance organisation:

The repair/overhaul trigger: The AD says if your engine has not been overhauled or had any repair since new, no further action is required. This seems straightforward - but the definition of "repair" is not defined in the AD. If the engine had a cylinder replaced due to leakage, is that a repair? Likely yes, because it involves removal of the cylinder assembly, which defines "connecting rod accessibility". A literal reading suggests any maintenance that physically disturbs the connecting rod would trigger the inspection requirement. However, if a cylinder was removed for a top overhaul (which may include piston ring replacement but not connecting rod work), the operator might argue that was not an overhaul. The AD does not distinguish between major and minor repairs. The cautious approach: if any maintenance work involving cylinder removal has ever been performed on the engine since new, the operator should assume the AD applies and inspect the records.

The 2,000-hour TIS clock: This runs on the connecting rod, not the engine. If the rod was replaced at some point (even with a non-affected rod), the TIS on that rod starts from installation. This is critical: an engine with 3,000 hours total but with a rod installed at 2,500 hours would have only 500 hours TIS on the rod. Conversely, an engine with 1,500 hours total time could have a rod with 1,500 hours TIS if it was the original rod. The AD does not require calibration of TIS - the operator must determine the rod's TIS accurately, which may be difficult if the logbook records are incomplete.

The accessibility trap: The AD says for rods with fewer than 2,000 hours TIS, replace "at the next engine overhaul, or next accessibility of the connecting rod, but no later than 2,000 hours TIS on the connecting rod." If an operator schedules a cylinder replacement for maintenance purposes (e.g., to fix a suspected leak) at 1,200 hours TIS, they must replace the connecting rod at that time even though they had planned to wait until the 2,000-hour overhaul. This could add unexpected cost to a routine maintenance event. The definition of "accessibility" is broad - any removal of a cylinder assembly. Operators must consider this whenever they have cylinder work.

The interaction with the FAA AD: The AD notes it refers to FAA AD 2006-10-21. An Australian-registered aircraft operating in the United States (or US-registered aircraft in Australia) must comply with both ADs. If the FAA AD has different compliance deadlines (e.g., a later effective date or different hour thresholds), the more stringent requirement applies. The source text does not reproduce the FAA AD, so operators should cross-check both.

The exemption for no prior overhaul: This might lead an operator to skip inspection and later discover that the engine received a repair that was not properly recorded. For example, a previous owner might have had a cylinder replaced at a repair station without it being documented as an overhaul. If the logbook does not show any repair, the operator relies on that; but if later an inspector finds evidence of repair (e.g., a cylinder with different serial number), the operator could be deemed non-compliant from the date the repair was actually done. The safe course is to physically inspect the connecting rod forging number and serial number, but the AD does not mandate that - it only requires inspection of records.

The prohibition on installation: This is absolute. Even if you have an affected rod in a crate that has never been used, you cannot install it. The rod has no value for installation. You might sell it as a paperweight only. But note that the prohibition applies to "any engine" - not just Lycoming 360/540 series. It could be used in a non-aviation application (e.g., stationary engine), but if used in any aircraft engine, it is banned.

Time limit for replacement: For rods with fewer than 2,000 hours TIS, the replacement must be done "no later than 2,000 hours TIS." If you have 2,000 hours exactly, you must comply before further flight - the AD does not give a grace period. Accurate hour tracking is essential.

Multiple rods affected: The AD applies to each connecting rod individually. An engine may have multiple rods (typically 4 or 6 cylinders). The inspection must identify each rod's serial number. It is possible that only one rod in an engine is affected while the others are not. The AD requires replacement of only the affected rod(s) - but the compliance deadline for that rod applies to the whole aircraft. So the operator must replace the affected rod according to its TIS, but the unaffected rods remain. The condition is not that all rods are affected.

Compliance with AD/LYC/116 requires a systematic approach that tracks the condition of each connecting rod in the engine. The following steps are based on the source text and standard aviation procedures:

Step 1: Determine if the AD applies to your aircraft.
Check if the aircraft has a Lycoming 360 or 540 series engine as listed in Table 1. If the engine is of a different series (e.g., 320, 580), the AD does not apply. Also check the engine model designation - the list includes many suffixes but is exhaustive. If your model appears, proceed.

Step 2: Determine if the engine has been overhauled or repaired since new.
Examine the maintenance records and engine logbook. If the logbook shows no overhaul or repair since the engine was first installed (i.e., it is original build), no further action is required. Keep the records showing this to prove compliance. If there is any record of an overhaul or repair, proceed.

Step 3: Inspect records for ECi connecting rods P/N AEL11750.
Look in the logbook for entries that identify the connecting rods installed. If the overhaul or repair facility used connecting rods from any manufacturer other than ECi (e.g., Lycoming OEM, Superior Air Parts, etc.), or if the part number is not AEL11750, no further action is required. If the records show ECi P/N AEL11750, proceed.

Step 4: Identify the serial number of the connecting rod.
The serial number is located on the connecting rod. If records are insufficient, you must physically inspect the rod by removing a cylinder assembly (which itself triggers the accessibility compliance for low-TIS rods - a catch-22). The forging P/N AEL11488 is raised letters on the web of the beam. The serial number follows the format "54/X" where X is the individual rod serial number. If the serial number is 54/7 or higher (lot 54, serial 7 and above), no further action is required. If the serial number is 54/6 or below (i.e., 54/1 through 54/6), the rod is affected.

Step 5: Determine time-in-service (TIS) on the affected connecting rod.
Calculate hours since the rod was installed. If the rod was installed during an overhaul, TIS starts from that overhaul date. If the rod was replaced later, TIS starts from that installation. Check the logbook for hour records at installation and current hours. If the rod has 2,000 or more hours TIS, action is immediate.

Step 6: Compliance actions based on TIS.

• If TIS >= 2,000 hours: The aircraft cannot be flown again until the affected connecting rod is replaced. Ground the aircraft. Schedule replacement immediately using a connecting rod with lot 55 or higher, or a different part number (e.g., Lycoming OEM). After replacement, a licensed aircraft maintenance engineer must endorse the logbook and record compliance with AD/LYC/116.
• If TIS < 2,000 hours: The rod does not need to be replaced immediately. However, you must replace it at the earliest of:
  • The next engine overhaul.
  • The next time a cylinder assembly is removed for any maintenance (accessibility event).
  • Before the rod reaches 2,000 hours TIS (whichever comes first).
    Mark the logbook with the remaining TIS allowable and set a reminder at 1,800 hours to schedule replacement.

Step 7: Prohibition on installation.
Do not install any ECi connecting rod P/N AEL11750 with SN 54/6 or lower into any engine after 31 May 2006. Dispose of such parts by mutilating them (cutting, crushing) to prevent inadvertent use. Record the disposal in the parts usage log if you are a maintenance organisation.

Step 8: Recordkeeping.
Ensure that all inspections, determinations, and replacements are documented in the engine logbook. Include:

• Date of inspection.
• Part number and serial number identified (or statement that not ECi AEL11750).
• TIS at time of determination.
• If replacement performed: part number and serial number of new rod, hours TIS at replacement, and signature of LAME.

Step 9: Consider alternative means of compliance.
If you cannot source a compliant rod within the required timeframe, apply to CASA for an alternative means of compliance under CASR Part 39. This may involve a risk assessment and engineering justification. Given that the AD has been in effect for many years, most affected rods have been replaced; historical compliance is expected.

Step 10: Recurring compliance.
This AD is a one-time action per affected rod. After replacement, the rod is no longer subject to the AD. There is no recurring inspection. However, if you sell the aircraft, disclose AD compliance in the logbook to avoid future disputes.

The compliance burden is primarily the cost of new connecting rods and labour (cylinder removal and rod replacement). Owners should budget for this and plan maintenance to coincide with other engine work to minimise downtime. The AD does not require a full overhaul - only rod replacement, but accessibility to the rod requires cylinder removal, which is a significant labour item.