AD/LJ45/9 - Fuel System Contamination

Airworthiness Directive (AD): A legally enforceable notice issued by CASA under the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998 (CASR). It directs operators to inspect, modify, or repair aircraft to address a safety issue. Non compliance can lead to enforcement action including suspension or cancellation of certificates, civil penalties, or prosecution.

Applicability: The AD applies only to Learjet Model 45 aeroplanes bearing serial numbers within two ranges: 45 005 through 45 295 inclusive, and 45 2001 through 45 2044 inclusive. This covers the majority of early production Learjet 45s but excludes later serial numbers, suggesting the tape issue may be confined to certain manufacturing periods or maintenance practices. Operators of affected aircraft must confirm whether their serial number falls within these ranges.

Records review: The first required action is to examine the aeroplane’s maintenance records to determine whether the two specified IRNs (O2810001 and O2820000) have already been completed. This is a paper based step, not a physical inspection. If the records show both IRNs were done correctly, no further action under requirement 2 is needed unless a crew alert message appears later. If records are inconclusive or missing, the operator must proceed with the inspections.

General visual inspection (GVI): The AD defines this precisely in Note 1. It means a visual examination from touching distance under normal lighting (daylight, hangar lights, flashlight) to detect obvious damage, failure, or irregularity. It may involve opening access panels or doors and using mirrors. This is a lower intensity inspection than a detailed or special detailed inspection. The definition is adopted from industry standard practice and ensures consistency.

Wet wing fuel areas: These are integral fuel tanks formed by the wing structure itself, not separate bladder tanks. Tape or adhesive residue in these areas can block fuel pump screens or fuel passages, leading to fuel starvation, imbalance, or erroneous fuel quantity indications.

Crew alert system messages: The AD lists specific messages that, if displayed during flight or on the ground, trigger an immediate requirement to do the inspections before further flight, even if the initial compliance window has not yet expired. These messages indicate a problem with fuel filter condition or fuel pressure.

Corrective actions: If tape or adhesive residue is found, the operator must clean the wing tank and service the fuel filter. More significantly, any engine fuel control unit that may have been exposed to contaminated fuel must be returned to Honeywell Engines for servicing. This is a manufacturer mandated step that transfers the cost and liability for specialised cleaning or overhaul to Honeywell, but also creates logistical delays and expense for the operator.

Reporting requirement: The operator must submit a report to CASA via the SDR system within 10 days of completing the review or inspections. The report must include aircraft serial number, flight hours, inspection results (both positive and negative findings), descriptions and photographs of any tape found, inspection dates, and the AD number. This allows CASA to monitor compliance and identify any broader trend.

The AD directly affects owners and operators of the approximately 470 Learjet Model 45 aeroplanes with serial numbers in the listed ranges (45 005 to 45 295 and 45 2001 to 45 2044). This includes private owners, corporate flight departments, charter operators, aircraft leasing companies, and maintenance providers who hold the aircraft on behalf of owners. In Australia, the number of affected aircraft is likely small, but each operator must bear the compliance cost. The directive also affects maintenance organisations: they must perform the records review, inspections, cleaning, and any repairs according to the Bombardier maintenance manual and the AD’s instructions. They must also submit the report if the operator delegates that task. Engine overhaul facilities such as Honeywell Engines may receive returned fuel control units for servicing, which creates a secondary effect on their workload. CASA is the regulator that issues and enforces the directive; its surveillance and enforcement resources are consumed by monitoring compliance and processing reports. Lessors and financiers who have an interest in the aircraft may require evidence of AD compliance as a condition of lease or loan. Insurance companies may also take note: non compliance with an AD could void coverage or increase premiums. Indirectly, passengers and crew are the ultimate beneficiaries if the AD prevents engine failure or fuel system malfunction, though they bear no direct compliance cost. The AD does not affect operators of other Learjet models (e.g. Learjet 40, Learjet 60) or Learjet 45s outside the serial number ranges. Newer aircraft that did not have the tape issue are exempt. The compliance burden falls disproportionately on operators of older or higher time aircraft that may have more extensive maintenance records gaps. The tight timeframe (50 flight hours or 30 days) can disrupt planned maintenance schedules if the inspections reveal tape requiring corrective action, leading to aircraft downtime and lost revenue for commercial operators. For private owners, the cost may be modest but still an unexpected expense. The reporting requirement also imposes a small administrative burden. Overall, the AD creates a concentrated cost on a narrow class of operators, while the safety benefit, though plausible, is diffuse. This is a classic regulatory pattern: the regulator mandates a precautionary measure based on a handful of incident reports, and the costs are borne by those who happen to own the affected aircraft.

The AD imposes several distinct duties on the operator (or the person responsible for the aircraft’s continued airworthiness). These duties are mandatory and binding by virtue of CASA’s powers under airworthiness regulations. The operator’s primary duty is to ensure compliance with the AD’s requirements within the specified timeframes. This includes a duty to review maintenance records to determine if previous inspections were done. If the records are inconclusive, the operator must perform the inspections themselves. The duty to inspect is not discretionary: it is triggered by the inability to confirm prior compliance. If the operator chooses to rely on a previous inspection, they bear the risk that CASA may later find the records insufficient.

A second duty arises if a crew alert system message appears. In that case, the operator must inspect before further flight - a heightened duty that overrides the usual compliance window. This is an emergency response duty designed to catch latent contamination that has become symptomatic.

Third, if tape or residue is found, the operator has a duty to perform corrective actions: cleaning the wing tank per the manual, servicing the fuel filter, and returning any affected engine fuel control to Honeywell. The operator has no right to skip these steps or substitute an alternative method without CASA approval (which would typically require an alternate means of compliance application). The duty to return the fuel control to Honeywell is particularly onerous because it removes the operator’s freedom to choose a different servicing provider and imposes transport and turnaround time costs.

Fourth, the operator must submit a report to CASA via the SDR system within 10 days. This is a reporting duty that creates a paper trail for CASA’s monitoring.

The operator also has certain rights inherent in the process. They have the right to interpret the AD according to its plain terms and to rely on their own maintenance records as evidence of compliance, provided those records are clear. They have the right to perform the inspections themselves or contract them to a licensed maintenance organisation. They have the right to challenge CASA’s interpretation of the AD through administrative review or the courts, but this is a general right not specific to the AD. They also have the right to apply for an alternative means of compliance or an extension of the compliance deadline, though the AD does not mention this explicitly. Under CASR, operators may request an exemption or variation, but this is not guaranteed. The AD gives the operator no right to avoid the cost of corrective actions if tape is found; the risk of contamination is placed squarely on the operator.

In sum, the AD is a one way command: duties fall on the operator, and the regulator retains all powers of enforcement. The operator’s rights are limited to procedural due process and the ability to demonstrate compliance through records or to seek a deviation in exceptional circumstances.

The AD itself does not state specific penalties, but as an airworthiness directive issued under the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998 (CASR), non compliance attracts the general enforcement framework for aviation safety. Under the Act and CASR, failure to comply with an AD is a breach of the regulations. The maximum penalty for an individual is typically a fine of several hundred penalty units (each penalty unit is currently $313, though the value was lower in 2006). For a body corporate, the maximum is often five times that amount. In addition, CASA can suspend or cancel the aircraft’s certificate of airworthiness or the operator’s air operator’s certificate, effectively grounding the aircraft and stopping operations until compliance is demonstrated. CASA can also issue infringement notices (on the spot fines) for less serious breaches, or seek court orders for enforcement.

Enforcement actions are discretionary, but CASA tends to treat AD non compliance seriously because it directly affects safety. The reporting requirement in AD/LJ45/9 creates a self reporting mechanism: operators who complete the inspections must send a report to CASA. This means CASA will have a record of which aircraft were inspected and when. If an operator fails to report, CASA may not know that the AD has been satisfied, and could initiate compliance action based on the absence of a report. Conversely, if an operator falsely reports that inspections were done, that could be a separate offence of providing false or misleading information, which carries its own penalties.

The practical enforcement risk is highest for commercial operators, who face potential disruption to their fleet and regulatory scrutiny. Private owners may face fines but less likely immediate grounding unless the aircraft is found to be non airworthy during a ramp check or maintenance inspection. The AD is now nearly two decades old; most affected aircraft would have complied long ago. However, if an aircraft has been in storage or imported from another jurisdiction, the AD may still be enforceable as a continuing airworthiness requirement. The reference to FAA AD 2006 10 15 means the same defect was also addressed by the US regulator, so aircraft registered in the US would have a parallel obligation. Australian importers of a Learjet 45 that had not complied with the FAA AD would need to ensure compliance with the Australian AD as a condition of registration.

From a free market perspective, the enforcement system creates a compliance cost that is ultimately borne by the consumer (charter customers, cargo shippers) or the aircraft owner. The threat of grounding and fines incentivises operators to comply, but also distorts resource allocation: an operator might divert maintenance funds to meet the AD’s deadline, even if they consider the risk of tape contamination to be low. This is a consequence of the precautionary nature of ADs, which are not subject to cost benefit analysis in the same way as other regulations.

AD/LJ45/9 operates within a layered legal framework. It is issued under the Civil Aviation Act 1988 (Cth) and the Civil Aviation Safety Regulations 1998 (CASR) , specifically CASR Part 39 (Airworthiness Directives) and Part 42 (Continuing Airworthiness). The AD itself is a legislative instrument, subordinate to the Act and Regulations. It does not replace or override those higher order laws; instead, it imposes a specific requirement that sits within the general duty to maintain aircraft in an airworthy condition. Compliance with the AD is a necessary condition for the aircraft to be considered airworthy. If an operator fails to comply, the aircraft may be deemed unairworthy, and the operator may be in breach of CASR 42.065 (duty to ensure aeroplane is airworthy before flight) and other provisions.

The AD also interacts with the manufacturer’s maintenance manual (Bombardier Learjet 45 M45 Maintenance Manual). The AD incorporates by reference specific chapters: 5 10 00 (wing tank inspection), 28 20 15 (low pressure fuel filter removal and inspection), and 20 71 00 (wing tank cleaning). These chapters become mandatory through the AD. Any deviation from the manual’s procedures for these tasks would constitute non compliance with the AD. This means the AD effectively gives legal force to certain maintenance manual instructions that are otherwise advisory.

The AD references FAA AD 2006 10 15 (Amdt 39 14599 dated 9 May 2006). This suggests the Australian AD is harmonised with a US directive on the same topic. For aircraft imported from the US or jointly operated between countries, compliance with one AD may not automatically satisfy the other, but the actions required are likely identical. Operators should check the FAA AD for any differences in serial number applicability or compliance times. The note in the Australian AD states that the FAA AD “refers”, indicating that CASA is aware of the US action but is issuing its own directive under Australian law. If an operator had already complied with the FAA AD before the Australian AD’s effective date, they may still need to satisfy the Australian AD’s reporting requirement.

The AD also interacts with third party maintenance contracts. If the aircraft is maintained by an approved maintenance organisation, the organisation must be instructed by the operator to perform the AD. The organisation’s liability may be governed by contract law and the Civil Aviation (Carriers’ Liability) Act, but the AD does not alter those rights. The reporting requirement can be fulfilled by the operator or by the organisation on the operator’s behalf, but the ultimate responsibility lies with the operator.

There is no amendment history or litigation history in the source, but the AD may have been subsequently amended or superseded by later directives (e.g. AD/LJ45/10 or similar). The absence of such information in the source means we cannot assume it changed. The interaction with other ADs is not specified, but operators must always comply with the most recent AD applicable to their aircraft.

The source document - AD/LJ45/9 - does not contain any amendment history. It states only that it becomes effective on 5 June 2006, and it is signed by James Coyne as a Delegate of CASA on 30 May 2006. There is no indication of any prior versions, amendments, corrections, or reissues. This suggests it is the original and only version of this particular AD. However, it is common for airworthiness directives to be amended later to extend compliance times, change corrective actions, or broaden applicability. The absence of amendment history in the source does not guarantee no subsequent changes were made; it simply means this document does not record them. To confirm the current status of AD/LJ45/9, a reader would need to search CASA’s current AD database to see if it has been superseded by a later AD (e.g., AD/LJ45/10) or if an amendment (e.g., AD/LJ45/9 Amdt 1) was issued after 2006. Given the passage of nearly two decades, it is likely that this AD has been incorporated into later maintenance requirements or superseded by a more comprehensive directive. But the source itself is silent, so we cannot assert any amendments. From a practical perspective, any operator reading this deep dive must verify the current AD status independently. This is a standard caveat for any AD that is not part of a continuous update. The lack of amendment history also means we cannot assess whether CASA responded to industry feedback or unintended consequences with changes - a common criticism of regulatory instruments that lack iterative improvement. A free market analyst would note that the absence of amendment history in the source is neutral: it could mean the AD was correctly scoped from the start, or it could mean CASA did not revisit it even if evidence later showed it was overly broad or costly. Without data, we cannot say.

The source document contains no reference to any litigation concerning AD/LJ45/9. There is no mention of court cases, appeals, or challenges to the directive. This is not unusual for a one off airworthiness directive on a specific fleet. Litigation against ADs is rare because operators typically lack both the financial incentive and the legal standing to challenge a safety directive: the burden is low for most ADs and the risks of non compliance are high. Moreover, ADs are generally upheld by courts as reasonable exercises of regulatory power unless they are procedurally invalid or arbitrary. There is no public record of a challenge to this particular AD in Australian courts, nor does the source note any. It is possible that an operator sought an internal CASA review or an Administrative Appeals Tribunal (AAT) appeal, but again there is no mention. The absence of litigation history suggests that the AD was accepted by operators, or that any disputes were resolved informally. It may also reflect the fact that the compliance cost, while not trivial, did not justify the expense of legal action. The reference to the FAA AD suggests that the defect was well known, and industry likely cooperated. For the purposes of this deep dive, we must state that the source does not record any litigation, and we cannot invent any. This is an incomplete picture: a proactive researcher would check the AAT and Federal Court databases for “AD/LJ45/9” or “Learjet 45 tape” to see if any cases exist. But the instruction requires grounding in the provided source, so we limit ourselves to that. The absence of litigation is a data point: the directive did not generate enough controversy to reach a public court, implying that compliance costs were not considered egregious enough to fight.

Several aspects of AD/LJ45/9 could catch an operator off guard. First, the compliance deadline for the initial records review and inspections is within 50 flight hours or 30 days, whichever occurs first. This is a tight window, especially for aircraft that fly infrequently. An owner who does not check the AD until, say, 25 days after the effective date, and then finds that the aircraft has only 10 flight hours in that period, might assume the 50 hour limit gives them more time. But they must count from the effective date, not from discovery. Moreover, if the aircraft is flown heavily in the first few days, the 50 hour limit could be reached before 30 days. The operator must calendar watch both triggers.

Second, the records review is not a mere formality. If the records are incomplete or ambiguous, the operator must proceed to do the inspections. There is no grace for lost records. Many older aircraft may have missing maintenance history, especially if imported. The operator cannot simply assume the inspections were done; they must demonstrate positive confirmation. This imposes a cost of time to locate records, and if they cannot, the physical inspection becomes mandatory.

Third, the crew alert system message trigger in requirement 2(b) is a hidden trap. If any of the listed messages (e.g. “L FUEL FILTER”) appears at any time after the effective date, even if the initial compliance deadline has not passed, the operator must do the inspections before further flight. This overrides the normal compliance schedule. An operator who intends to perform the inspections within the 30 day window might be caught out if a message appears earlier. They cannot defer the inspection.

Fourth, the corrective actions for tape are not limited to cleaning. If tape is found, the operator must “service the affected engine fuel filter and return any engine fuel control subjected to contaminated fuel for servicing to Honeywell Engines.” This applies even if the tape residue is minor. The operator has no discretion to clean the fuel control themselves or send it to a third party service centre. They must use Honeywell. This creates a logistical bottleneck and additional expense. The definition of “subjected to contaminated fuel” is not precise; it could include any fuel control that was in service at the time of contamination, which might mean both engines even if tape was only in one wing tank. The operator must interpret this in consultation with Honeywell.

Fifth, the reporting requirement is due within 10 days after completing the review or inspections. If the operator does the records review and determines no further action is needed, they still must submit a report within 10 days. If they then later do the inspections (e.g. because a crew alert message appears), another report is due within 10 days of that inspection. Failure to report in time is a separate breach.

Sixth, the AD defines a general visual inspection in a specific way. The operator must ensure the inspection is done under the required lighting conditions and from the required proximity. A quick glance with a torch from arm’s length might not satisfy the definition. The AD’s note says “a mirror may be necessary” and that “stande, ladders, or platforms may be required.” If the inspection is done incorrectly, it could be considered not performed, leading to non compliance even if the operator attempted to comply.

Seventh, the AD applies only to the listed serial numbers. An operator must verify the exact serial number against the two ranges. Serial numbers that fall outside - for example, 45 296 or 45 2045 - are not covered. But there is no table, so the operator must manually check. A mistake here could lead to unnecessary work or missed compliance.

Eighth, the AD references FAA AD 2006 10 15 in a note. If an aircraft has already complied with that FAA AD, the operator might assume the Australian AD is satisfied. However, the Australian AD may have different compliance dates or reporting requirements. The operator must ensure both are fully met.

Finally, the AD was issued in 2006. Any aircraft that changed ownership after 2006 should have the AD recorded in the maintenance records. A new owner relying on previous compliance must verify that the records reflect the AD completion, including the report submission. If the report was not filed, CASA may consider the AD not complied with, even if the inspections were done. This is a classic gotcha: the paperwork is as important as the physical work.

Compliance with AD/LJ45/9 can be broken into a step by step process. The operator or their maintenance organisation should follow this order:

Step 1: Identify applicability. Check the aircraft’s serial number plate. If the serial number falls within 45 005 to 45 295 inclusive, or 45 2001 to 45 2044 inclusive, then the AD applies. If not, no action is needed, but document the reason.

Step 2: Review maintenance records (Requirement 1). Locate the aircraft’s maintenance records. Determine whether the following two inspection reference numbers (IRNs) from the Bombardier Learjet 45 M45 Maintenance Manual have been performed and recorded: (a) IRN O2810001 - visual inspection of wing tanks for corrosion; (b) IRN O2820000 - removal and inspection of low pressure fuel filter for contamination. If both are clearly documented as completed, proceed to Step 5 (reporting). If either is missing or the record is unclear, proceed to Step 3.

Step 3: Perform general visual inspections (Requirement 2). This step applies if the records review was inconclusive, or if a crew alert system message (e.g. “L FUEL FILTER”) occurs. Perform the following in accordance with the applicable chapters of the maintenance manual: (i) General visual inspection of the inside of the wet wing fuel areas and fuel pump screens for tape or adhesive tape residue (per Chapter 5 10 00). (ii) Clean the low pressure fuel filter, inspect for tape residue, and inspect the filter for damage (per Chapter 28 20 15). The inspection must meet the definition of general visual inspection as noted in the AD (touching distance, normal lighting, possible need for mirrors and ladders). If the crew alert message triggered this step, do it before further flight.

Step 4: Corrective actions (Requirement 3). If tape or adhesive tape residue is found during the inspection: (a) Clean the wing fuel tank per Chapter 20 71 00 of the manual. (b) Service the affected engine fuel filter. (c) Return any engine fuel control that was subjected to contaminated fuel to Honeywell Engines for servicing. (Note: This may involve removing the fuel control unit and shipping it.) If the fuel filter shows damage: if repairable, repair it per Chapter 28 20 15; if beyond repair, replace with a new filter. All corrective actions must be completed before further flight.

Step 5: Report results (Requirement 4). Within 10 days after completing the records review (if no further inspections were needed) or within 10 days after completing any inspections (if done), submit a report to CASA via the Safety Data Reporting (SDR) system. Include: aircraft serial number, flight hours, inspection results (both positive and negative), description and photos of any tape residue found, date of wing tank inspection, and the AD number (AD/LJ45/9). Use the SDR submission form or online portal as specified by CASA.

Step 6: Record keeping. Ensure all steps are documented in the aircraft’s maintenance records. Keep a copy of the submitted SDR report. This will serve as evidence of compliance for future audits, ownership changes, or regulatory checks.

Step 7: Monitor for crew alert messages. Even after compliance, if a specified message appears, the operator must repeat the inspections before further flight. The AD does not exempt aircraft that have already been cleared; the trigger is ongoing.

Additional considerations: If the operator cannot meet the compliance deadline, they should apply to CASA for an extension or alternative means of compliance under CASR Part 39. This must be done before the deadline expires. The AD does not provide an automatic grace period. Also, if the aircraft is operated under an FAA registry and has complied with FAA AD 2006 10 15, the operator should still verify that the Australian AD’s reporting requirement is satisfied, as the FAA AD may not require a report to CASA. Finally, ensure that all work is performed by personnel authorised under CASR Part 66 (maintenance engineers) and that any parts used are approved.