AD/F100/93 - On-Ground Wing Leading Edge Heating System

On‑Ground Wing Leading Edge Heating System (OGWLEHS). This is a modification that connects the engine anti‑icing selection to the wing anti‑icing system on the ground. In the standard configuration, the wing anti‑icing system operates only in flight. The OGWLEHS, when installed, activates the wing leading‑edge heating whenever the crew selects engine anti‑icing ON while the aircraft is on the ground. The purpose is to prevent the accumulation of ice, frost or snow on the wing leading edges during ground operations. The source does not describe the system’s design in detail beyond stating that it is a design change. The heat is presumably drawn from engine bleed air, similar to the in‑flight system. Operators must install the system using the service bulletin and the applicable appendix for their specific serial number, which suggests that the physical retrofit differs across aircraft. Notably, the source identifies 13 specific serial numbers (11496, 11518, 11562, 11566, 11567, 11568, 11571, 11572, 11575, 11579, 1581, 11582, 11583) that were delivered with the OGWLEHS already installed, but notes that it may have since been removed or deactivated. Those aircraft are also subject to the directive, implying that if the system was removed, it must be reinstalled.

Clean aircraft concept. This is the regulatory requirement that an aircraft must be free of ice, frost, snow, or other contamination on critical surfaces before take‑off. The source emphasises that the OGWLEHS does not replace the operator’s responsibility to maintain this concept. The operator must still conduct inspections whenever icing conditions exist, apply de‑icing and/or anti‑icing fluids according to an approved winter operation program, and follow the decision logic in that program. The only potential relief, which is highly conditional, is that under certain AFM‑defined conditions, the tactile inspection of the upper surface of the wing leading edge after fluid treatment may be waived if the OGWLEHS was used. The source does not specify those conditions; it refers only to the Approved Flight Manual.

Exemption. The directive permits an operator to apply for an exemption from the installation requirement if they can demonstrate that ground‑icing conditions as defined in the AFM are “completely excluded over the full calendar year and the operator’s complete operating network”. This is a very high bar. It requires not only that the aircraft never operate in environments where icing could occur, but also that the possibility is excluded entirely. An operator who operates only from hangars in a desert climate might qualify, but any operator with seasonal variation or a network spanning different climates would struggle. The exemption process is described only in Note 3; the source does not state the application procedure, fee, or review period. It is left to the operator to seek relief from CASA.

Relationship between design change and operational procedures. A key conceptual issue in the directive is the trade‑off between a hardware mandate and improvements in human procedures. The background states that the events were caused by operational (human) factors, but that a design change is more effective in reducing the potential for further accidents. This implies a belief that the system reduces the consequences of human failure, or that it is harder for crews to make mistakes when the system is automatically heating the leading edges. However, the source also notes that the system “will certainly aid” but does not replace operational procedures. The directive therefore creates a two‑layered risk management: the hardware provides a second line of defence, but the primary line remains the operator’s winter operation program. For operators who already have robust de‑icing and inspection procedures, the marginal safety benefit of the OGWLEHS may be small, while the cost is significant. The directive does not allow operators to choose a different safety investment, such as enhanced training or additional ground equipment, as a substitute.

Tactile inspection relief. The only specific procedural relief that the OGWLEHS can provide, under the AFM conditions, is waiving the tactile (touch) inspection of the upper surface of the wing leading edge after de‑icing or anti‑icing treatment. This is a minor reduction in the inspection burden, not a waiver of any other check. The operator must still conduct all other pre‑take‑off contamination checks. Therefore, the operational benefit is limited to saving a small amount of ground time and effort, and only when the AFM conditions are met. The source does not list those conditions, so operators must review their specific AFM.

Approved Flight Manual (AFM). The AFM is the governing document for each aircraft. The directive refers to it multiple times, particularly for the conditions under which the OGWLEHS can relieve the tactile inspection, and for the definition of ground‑icing conditions used in the exemption criteria. Operators must ensure that the AFM is updated to reflect the OGWLEHS installation and any new operating limitations or procedures.

Aircraft operators. The primary affected parties are the operators of any Fokker F28 Mark 0070 and Mark 0100 aircraft registered in Australia, or any foreign aircraft operated in Australia under Australian airworthiness requirements. The directive applies to all serial numbers, not just those originally delivered without the system. This includes airlines, charter operators, freight operators, private owners, and leasing companies. The compliance burden falls on whoever holds the airworthiness responsibility for the aircraft. For operators with large fleets of these aircraft, the cost of retrofitting multiple aircraft within 24 months may be substantial, particularly if the modification requires significant downtime per aircraft. The directive does not differentiate between operators based on utilisation, route network, or winter climate; a tropical operator that never sees frost is subject to the same mandate as an arctic operator. The only relief is the narrow exemption for operators who can completely exclude ground‑icing conditions year‑round and network‑wide.

Maintenance organisations. Approved maintenance organisations (AMOs) that perform the installation must have the capability to follow the service bulletin instructions and the applicable appendix. They may need to source the kit from Fokker (or its successor) and train technicians. The work likely involves wiring, bleed‑air ducting, and control logic changes, as well as testing and certification. The cost of the installation will be passed on to operators. The directive does not specify any specific approval for the installing organisation beyond the normal Part 145 or equivalent requirements.

Regulators. CASA is the issuing authority, and the directive is made under the Civil Aviation Safety Regulations. EASA approved the original design change, and subsequent revisions to the service bulletin must be approved by EASA. There is also a reference to EASA AD 2009‑0008, meaning that a parallel directive exists in Europe. The directive was signed by James Coyne as Delegate of CASA. CASA will also handle any exemption applications and enforce compliance. The effectiveness of the directive depends on CASA’s ability to oversee the 24‑month compliance window and to take enforcement action against non‑compliant operators.

Aircraft manufacturers and type certificate holders. Fokker Services (or any entity holding the type certificate) created the service bulletin and the OGWLEHS design. The directive relies on the continued availability of the modification kit and the service bulletin. If the manufacturer is no longer supporting the aircraft, operators may face difficulty obtaining the required parts. The source does not address what happens if the kit is unavailable. The directive is dated 2009, so availability may be an issue for operators today.

Aircraft owners and financiers. Owners who lease aircraft to operators may be contractually required to ensure compliance. The retrofit cost may affect the residual value of the aircraft. An aircraft that is not compliant with this AD cannot be operated legally in Australia, and may be difficult to sell or lease to operators in jurisdictions that have adopted similar ADs.

Insurers. The existence of the AD may affect liability and insurance premiums. If an operator fails to comply and then has an icing‑related incident, the insurer could deny coverage or the operator could be found negligent per se. Conversely, compliance may be used as evidence of reasonable care, though the directive itself does not replace operational procedures.

Third parties affected indirectly. Passengers, freight customers, and the general public are ultimately the intended beneficiaries of the safety improvement. However, the cost of compliance may be passed on through ticket prices or freight rates. If the retrofit costs are high enough, some operators may retire the aircraft type earlier than planned, potentially reducing capacity in the market.

Operators who already have the OGWLEHS. Even if the system is already installed, the directive may require checking that it is still operational and that the installation matches the current service bulletin. If the system was later removed or deactivated, the operator must reinstall it. This affects operators who may have thought they were ahead of the requirement.

Duty to install. Every operator of an affected aircraft must install the OGWLEHS within 24 calendar months after 12 March 2009 - that is, by 12 March 2011. The installation must follow the Accomplishment Instructions of Fokker SBF100‑30‑018, Revision 1 or later EASA‑approved revision, and the correct appendix for the aircraft’s serial number. The duty is absolute: there is no provision for extensions based on cost, difficulty, or operational impracticality, except the exemption noted below. The source does not specify a minimum equipment list (MEL) relief; presumably, if the system is not installed, the aircraft cannot be operated.

Duty to maintain the clean aircraft concept. The directive explicitly states that modification does not relieve the operator of the responsibility to maintain the clean aircraft concept. The operator must still perform appropriate inspections whenever icing conditions exist, apply de‑icing and anti‑icing fluids based on an approved winter operation program, and comply with all relevant regulations. The only exception is the possible relief from tactile inspection under AFM conditions. This duty coexists with the OGWLEHS; the system is an addition, not a replacement.

Right to seek exemption. An operator may apply to CASA for an exemption from the installation requirement if they can demonstrate that ground‑icing conditions as defined in the AFM are completely excluded over the full calendar year and the operator’s complete operating network. This is a right, but the burden of proof is heavy. The operator must document that no part of their network ever experiences icing conditions, and that this is true for the entire year. The source does not specify the form of the application, the evidence required, or the processing time. Operators should be prepared for a detailed assessment.

Right to rely on the OGWLEHS for limited procedural relief. When the OGWLEHS is used and the aircraft is operated in accordance with the AFM, the operator may be relieved of the requirement to perform a tactile inspection of the upper surface of the wing leading edge after treatment with de‑icing or anti‑icing fluid. This relief is conditional upon the specific circumstances described in the AFM. The operator has a right to use that relief, but they also have a duty to ensure that all other pre‑take‑off checks are performed.

Duty to update the AFM. The operator must ensure that the AFM reflects the installation of the OGWLEHS and the associated operating conditions. The source does not state who is responsible for updating the AFM - it may be the manufacturer or the operator, depending on the regulatory framework - but the operator is ultimately accountable for having an approved AFM that covers the modification.

Duty to comply with future revisions. The directive requires installation in accordance with Revision 1 or “later revision approved by EASA”. This means that if the service bulletin is revised after the 2009 date, operators may need to update their installation to the later revision to remain compliant. The source does not provide a grace period for future revisions. Operators must monitor EASA approvals for SBF100‑30‑018.

Operator’s right to choose who does the installation. The directive does not mandate that the installation be performed by a specific organisation. Any appropriately approved maintenance organisation can carry out the work, provided they have the capability and instructions. This gives operators some flexibility in managing costs and downtime.

No right to delay for cost reasons. There is no provision in the source for an operator to delay compliance based on financial hardship, parts availability, or scheduling constraints. The 24‑month compliance time is fixed. Operators who cannot achieve compliance within that period would be in breach and could face enforcement action.

Duty to maintain the system thereafter. Once installed, the OGWLEHS must be maintained in airworthy condition. Future maintenance actions, including repairs and component replacements, must continue to meet the approved design standards. If the system fails, the aircraft may still be operated under MEL provisions if the regulations allow, but the source does not discuss that.

The source itself does not specify penalties for non‑compliance with AD/F100/93. That is typical for an airworthiness directive: it is a mandatory requirement under the Civil Aviation Safety Regulations (CASR), and the penalty provisions are contained in the broader regulatory framework, not in the AD itself. For Australian aircraft, failing to comply with an AD is a breach of the airworthiness requirements. Under the Civil Aviation Act 1988 and CASR, the maximum penalties for operating an aircraft not in compliance with an applicable AD can be significant. For an individual, fines may run to tens of thousands of dollars; for a body corporate, the maximum penalties are higher, and may include imprisonment in extreme cases where operations continue despite a known safety risk. The source does not quantify these, so the analysis must note the absence and refer to the general law.

CASA is the enforcement body. It has powers to issue infringement notices, apply to a court for injunctions, suspend or cancel an Air Operator’s Certificate (AOC) or a Certificate of Registration, and take other administrative action. The directive becomes effective on 12 March 2009, and compliance is required within 24 months. After 12 March 2011, any aircraft not modified may not be lawfully operated. If CASA detects an aircraft operating without the OGWLEHS after that date, it could ground the aircraft and take enforcement action.

The source does not discuss a system for self‑reporting or voluntary disclosure. Operators who discover they are non‑compliant may consider using CASA’s voluntary reporting scheme if one exists, but the directive itself offers no leniency. The 24‑month compliance window is generous by AD standards, so CASA would likely treat late compliance as a deliberate breach unless the operator can demonstrate that they were unable to comply for reasons beyond their control, such as parts unavailability or a natural disaster. However, the source does not provide a mechanism for extensions.

In the event of an accident or incident involving ice contamination, non‑compliance with this AD could be used as evidence of negligence or a breach of duty. Even though the directive says the events were caused by operational factors, a prosecutor or civil plaintiff could argue that the operator failed to take a required safety step that could have prevented the accident. This creates a liability risk beyond the direct CASA penalty.

For operators who have already installed the system but later remove or deactivate it, the AD requires that it be present and functioning. Removing it after compliance would also be a breach, unless the operator obtains an exemption.

There is no internal enforcement mechanism within the AD itself, such as a reporting requirement. The AD simply states the requirement and the compliance date. Enforcement relies on CASA’s surveillance and inspection programs. Given that the aircraft type is relatively old, CASA may rely on scheduled maintenance checks and record reviews to confirm compliance.

The background mention that the events were caused by operational factors suggests that CASA may focus on operational compliance as well. However, the AD itself does not mandate any specific operational inspection or training beyond the installation.

EASA AD 2009‑0008. The source notes that EASA AD 2009‑0008 refers, indicating that a parallel directive exists in the European regulatory system. For aircraft that are imported from or operated in Europe, the EASA AD imposes similar requirements. Australian operators who also fly in Europe must comply with both, but the installation requirements are aligned because the source requires installation per a service bulletin approved by EASA. There may be differences in compliance times or exemptions, but the source does not detail them. Operators should check the EASA directive for any additional operational restrictions.

Clean aircraft concept regulations. The source repeatedly emphasises that the OGWLEHS does not relieve the operator from the clean aircraft concept. This concept is embedded in various regulations, including CASR Part 91 (General Operating and Flight Rules) and possibly Part 121 (Air Transport Operations - Aeroplanes) and Part 135 (Air Transport Operations - Helicopters and Small Aeroplanes). The operator must still comply with all applicable rules regarding ground icing, pre‑take‑off inspections, and de‑icing/anti‑icing. The AD does not override those rules; it adds a design feature that may slightly modify the inspection procedure.

Approved Flight Manual (AFM). The interaction with the AFM is direct: the OGWLEHS installation must be incorporated into the AFM. The AFM is an approved document under CASR, and any changes require regulatory approval. The relief from tactile inspection only applies under specific AFM conditions. Therefore, the AD and the AFM must be consistent. If the AFM does not contain the conditions for tactile inspection relief, the operator cannot rely on that relief. Operators must ensure the AFM is revised accordingly.

Winter operation program regulations. The source requires that the operator have an approved winter operation program, with decision logic for de‑icing and anti‑icing. This is likely required by other regulations, such as CASR Part 121 or Part 135, or by the operator’s AOC. The AD does not prescribe the content of that program, but it assumes its existence. The OGWLEHS may be integrated into the program, but the operator has discretion.

Other airworthiness directives. The AD does not mention other ADs, but the aircraft type is subject to many ADs over its life. Compliance with AD/F100/93 must be tracked alongside other ADs. Some ADs may conflict or impose additional modifications that affect the OGWLEHS installation. Operators must maintain a comprehensive AD status for each aircraft.

Part 145 maintenance regulations. Installation of the OGWLEHS is a major modification. It must be performed by an organisation approved under CASR Part 145 (or equivalent foreign approval). The modification likely requires a certified release to service. The AD does not specify any additional approval beyond the service bulletin.

Exemption regulations. The right to apply for an exemption is under the general exemption powers in the Civil Aviation Act 1988. The process, criteria, and timeframes are set out in the Act and regulations, not in this AD. Operators seeking an exemption must follow those procedures.

Liability laws. As noted in the penalties section, non‑compliance may affect civil liability in the event of an accident. This AD interacts with tort law, workers’ compensation, and insurance policies. Operators should ensure that their compliance status is documented and maintained.

International obligations. Australia is a signatory to the Chicago Convention, and CASA’s ADs are part of the state’s safety oversight. Other states may accept this AD as part of their validation of Australian‑registered aircraft. If an Australian‑registered Fokker F100 operates in another country, the local aviation authority may require evidence of compliance with this AD.

Manufacturer’s service bulletins. The AD mandates installation per SBF100‑30‑018, Revision 1 or later. The service bulletin itself is a manufacturer’s document, not a regulation. However, by referencing it, the AD gives it regulatory force. If the bulletin contains errors or becomes obsolete, the operator must use a later revision approved by EASA. This creates a dynamic interaction: the operator must track EASA approvals for bulletins that may not be directly under CASA oversight.

The source itself does not provide any amendment history for AD/F100/93. It appears to be the original issue of the directive, bearing the number AD/F100/93 and the issue identifier 3/2009. The document is dated 27 January 2009 and becomes effective 12 March 2009. There is no mention of previous amendments, revisions, or supersedure. The directive may have been amended or replaced after 2009, but that is not in the source. The source is a single‑page document (plus the image) containing the directive text. The only reference to a revision is in the service bulletin: SBF100‑30‑018 or Revision 1 or later revision. That refers to the manufacturer’s document, not to the AD itself.

Given that the source does not contain an amendment history, any discussion of later changes would be speculation. The deep dive must be grounded in the source. Therefore, this section can only state that no amendment history is provided in the source, and that the directive appears to be the original 2009 version. The user should verify with CASA’s current AD database whether the directive has been amended, reissued, or cancelled. The directive may have been superseded by a later AD that consolidates or modifies requirements, but the source does not indicate that.

Operators who are currently relying on this AD must ensure they have the most current version. The source is dated 2009, and airworthiness directives are frequently amended. CASA’s online AD register would show the current status. The source notes that the service bulletin may have later revisions approved by EASA, which indicates that the design standards can change without amending the AD itself. That creates a form of de facto amendment: if a new revision of the bulletin is approved, the installation standard for future compliance changes, but the AD text remains the same.

The directive also references EASA AD 2009‑0008, which may have been amended in Europe. Australian operators should monitor both jurisdictions.

In summary, the source provides no amendment history for the AD itself. The analysis must acknowledge that limitation and advise readers to verify the current status. Compliance professionals should not rely solely on a 2009 printed copy.

The source does not cite any litigation history related to this AD. It mentions a fatal accident in 1993 and two serious events where aircraft were written off, but those are accident investigations, not court cases. No civil or criminal proceedings are referenced. The directive itself is a regulatory response to those events, but any subsequent legal challenges to the AD, such as judicial review proceedings, are not mentioned.

Given the age of the directive (2009), it is possible that some legal disputes have arisen. For example, an operator could have challenged the AD on procedural grounds (e.g., whether CASA had the power to issue it), or on economic grounds (e.g., an argument that the cost outweighs the benefit, though such challenges rarely succeed). However, the source provides no information about any such cases. The deep dive must not invent cases.

The background statement that the events were “established to have been caused by operational (human) factors instead” of design causes may be relevant in any litigation where the AD is used as evidence of industry practice. In a civil suit arising from an icing accident, a plaintiff might argue that the AD shows that a reasonable operator would have installed the OGWLEHS. Conversely, a defendant operator could argue that the accident was caused by operational failures, not the lack of the system, and that the AD itself acknowledges that the system does not replace operational procedures. The AD’s own language could cut both ways.

There is no mention of any class action or enforcement action by CASA against non‑compliant operators. That does not mean none occurred, but the source does not discuss it.

The directive’s reference to “at least two serious winter operation events” suggests that those events may have been investigated by the Australian Transport Safety Bureau (ATSB) or an equivalent body. The results of those investigations may have been published, but they are not part of the source.

For the purposes of this deep dive, the litigation history section must state that the source does not contain any litigation history. Any further analysis would require external research, which is not permitted under the instructions. The user is a serious researcher and can follow up independently.

The OGWLEHS is not a substitute for operational procedures. The directive explicitly states that the system “does not replace the required procedures to prevent take‑off with contaminated wings”. An operator who relies on the system to avoid de‑icing or inspections is in breach of other regulations. The only procedural relief is a possible waiver of the tactile inspection of the wing leading edge’s upper surface, and that is conditional on AFM provisions. This is a classic regulatory trap: the existence of the hardware may create a false sense of security. Operators must maintain diligence and ensure that crews are trained not to assume the system will clear contamination.

The exemption is nearly impossible to obtain. To qualify, an operator must demonstrate that ground‑icing conditions are “completely excluded over the full calendar year and the operator’s complete operating network”. This means no frost, no snow, no freezing fog, no ice‑forming conditions at any airport the aircraft operates to, at any time of year. For most operators, this is unattainable. Even an operator based in tropical Australia could encounter icing if they fly to a cold climate airport, or if the aircraft is parked overnight in a cold hangar. The exemption may effectively be unavailable, meaning the installation is mandatory for almost all operators.

The 24‑month compliance clock started 12 March 2009. This directive is from 2009. Any operator acquiring an F28 Mark 0070 or 0100 today must ensure it is already compliant. If it is not, the aircraft cannot be operated. The compliance date has long passed. The “gotcha” is that a new owner may assume they have a grace period, but they do not. The aircraft must have been modified before the current owner took possession. If not, the owner must ground the aircraft until the OGWLEHS is installed, which could take weeks or months.

The system may have been removed or deactivated. The directive lists 13 serial numbers that were delivered with the system, but notes that it “may have since been removed or deactivated”. If you own one of those aircraft, and the system is not present or not functional, you are non‑compliant. The system must be restored. Merely having the system installed at manufacture is not sufficient; it must be operational.

The service bulletin is controlled by EASA and may have multiple appendices. The installation must be per SBF100‑30‑018 Revision 1 or later, with the correct appendix for the aircraft serial number. Using the wrong appendix could result in an incorrect installation. Operators must ensure they have the exact revision and appendix specified. The source does not list which appendix applies to each serial number; that is left to the service bulletin. An operator who orders the wrong kit or instructions could waste time and money.

No MEL relief specified. The directive does not state whether the OGWLEHS can be deferred under a Minimum Equipment List. Typically, an AD‑mandated system may be MEL‑able if it is not essential for flight safety under all conditions. But the fact that the AD background says the system is an additional safety feature suggests it might be MEL‑able. However, the source does not include that information. An operator who wants to defer the system after installation should check with CASA and the AFM. It is possible that the system is not required for dispatch, but that risk is not addressed.

The system only activates when engine anti‑icing is selected ON. If the crew does not select engine anti‑icing on the ground, the OGWLEHS does not operate. The directive does not mandate that engine anti‑icing be selected in all ground‑icing conditions. That remains a crew decision. So the system’s effectiveness depends on proper crew action. A crew that forgets to select engine anti‑icing will not benefit from the system.

Coordination with other ADs. The Fokker F100 series is subject to many ADs. This particular AD interacts with others that may affect the same systems. For example, an AD on bleed air valves may affect the OGWLEHS functionality. Operators must manage the cumulative burden of multiple modifications.

Cost of compliance for a single aircraft may be high. The source does not give a dollar figure, but retrofitting a bleed‑air heating system on an older aircraft can involve labour, parts, and certification costs. For an aircraft with low residual value, the cost of this AD might exceed the aircraft’s market value, leading to early retirement. Operators should perform a cost‑benefit analysis before committing, but the AD does not allow an opt‑out.

Recordkeeping. Operators must maintain records of compliance. If the installation was performed using an earlier revision of the service bulletin, but the AD now requires a later revision (approved by EASA), the operator may need to update the installation. The AD states “Revision 1 or later revision”, meaning that if a later revision exists, the installation must be to that revision. An operator who installed per the original SBF100‑30‑018 (not Revision 1) is non‑compliant.

Compliance with AD/F100/93 requires a systematic approach. Given that the directive is from 2009 and the compliance date has passed, the steps below assume an operator is bringing an aircraft into compliance now, or verifying compliance.

1. Determine applicability. Confirm that the aircraft is a Fokker F28 Mark 0070 or Mark 0100, any serial number. Check the aircraft’s type certificate and registration. If the aircraft is one of the 13 serial numbers listed in Note 1, verify whether the OGWLEHS is still installed and functional. If it was removed or deactivated, treat the aircraft as needing installation.

2. Check current compliance status. Review the aircraft’s maintenance records and AD status. Look for evidence that the OGWLEHS was installed in accordance with SBF100‑30‑018, Revision 1 or later revision approved by EASA, with the correct appendix. Verify that the system is operational and that the AFM has been updated accordingly. If there is any doubt, or if the installation was done per an earlier revision, the aircraft may be non‑compliant.

3. Obtain the correct service bulletin and appendix. Contact Fokker Services or the current type certificate holder for the latest revision of SBF100‑30‑018. Identify the correct appendix for the aircraft’s serial number (Roman numerals I through VIII). Ensure the revision is approved by EASA. The directive allows any later revision, so always use the most current.

4. Perform the installation. Engage an approved maintenance organisation with the capability to perform the modification. The work will involve installing the OGWLEHS, likely including wiring, bleed air connections, control logic, and possibly control panel modifications. Follow the Accomplishment Instructions exactly. Use only the approved parts. The maintenance organisation must issue a certified release to service.

5. Update the Approved Flight Manual. After installation, the AFM must be revised to include the OGWLEHS. In particular, the AFM should describe the conditions under which the tactile inspection of the wing leading edge upper surface may be waived. The source says that relief applies only under “certain specific conditions described in the AFM”. The operator must ensure that the AFM contains those conditions and that the flight crew is trained. This may require coordination with the manufacturer or CASA for the AFM revision.

6. Record compliance. Document the AD compliance in the aircraft’s continuing airworthiness record. Include the service bulletin number and revision, the date of installation, and the release to service. This is essential for future audits, transfers, or inspections.

7. Review winter operation program. Ensure that the winter operation program is updated to include the OGWLEHS. The program should specify when the system is to be used, how it interacts with de‑icing and anti‑icing fluids, and the conditions for tactile inspection relief. The program must be approved by CASA if required by the operator’s AOC.

8. Train flight crews. Crews must understand that the OGWLEHS does not replace the clean aircraft concept. They must know when to select engine anti‑icing on the ground to activate the system, and under what AFM conditions they may skip the tactile inspection. Over‑reliance is a risk; training should emphasize that the system is an aid, not a substitute.

9. Consider an exemption if applicable. If the operator can honestly demonstrate that ground‑icing conditions are completely excluded year‑round and across the entire network, apply to CASA for an exemption from the installation requirement. Prepare evidence: climate data, airport reports, operational procedures. The threshold is very high, so this step is not realistic for most operators.

10. Monitor for bulletin revisions. The directive requires installation per Revision 1 or later revision. If EASA approves a later revision after the installation, review whether it imposes any new requirements that must be incorporated. The directive does not give a grace period for future revisions, so operators must stay current.

11. For new acquisitions. Before purchasing or leasing an affected aircraft, verify compliance with this AD. Request records showing the system was installed per the current service bulletin and that the AFM is updated. If the aircraft is non‑compliant, negotiate the cost of retrofit into the transaction or refuse the aircraft.

12. Ongoing maintenance. Include the OGWLEHS in the aircraft’s maintenance program. Ensure routine checks and component replacements are scheduled. If a component fails, repair it promptly or determine if the aircraft can be dispatched under any available MEL relief (although the AD itself does not provide that). Keep the system operational.