AD/AMD 50/38 - Electrical Power Feeder Inspection

The central concept is the “airworthiness directive” itself, a binding regulatory instrument issued under the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998. An AD is not optional; it is a legally enforceable requirement that overrides any operator’s maintenance schedule or judgment. This particular AD is a “one‑time” directive rather than a recurring inspection, because the defined actions are terminating: once both the inspection and modification (or the modification alone if damage triggers it) are completed, no further recurring checks are mandated by this AD. The terminating action is explicitly tied to implementation of both Dassault Service Bulletins , F900‑358 and F900‑359 for the Falcon 900, or F900EX‑241 and F900EX‑251 for the Falcon 900EX , or later EASA‑approved revisions. This ties the AD to the manufacturer’s engineering solution, meaning the operator cannot substitute its own design or method unless CASA approves an alternative means of compliance (though no such approval is mentioned in the source).

Another key concept is the definition of compliance deadlines. For the initial inspection, the operator must act within either 330 hours time in service (TIS) or seven months after the effective date, whichever comes first. “Time in service” is the standard measure of hours flown, so an aircraft that flies infrequently may still trigger the seven‑month deadline. For the corrective actions if damage is found, compliance is required “before further flight” , a strict grounding provision. For the modification of the partition wall, the deadline is “at the first time the partition wall is removed, but no later than 3,750 flight cycles or 74 months after the effective date”. This creates a situation where an operator who removes the partition wall for any other maintenance reason earlier than those limits must accomplish the modification at that time. Conversely, an aircraft that never has its partition wall removed must comply with the later of the cycle or month limit.

The directive also defines the population by serial number: Falcon 900 serial numbers 188 through 202, and Falcon 900EX serial numbers 82 through 146, with exclusions for aircraft that have already incorporated Dassault Modification M3891 or both of the relevant service bulletins. This means the AD is retrospective in effect: it applies only to aircraft still in the pre‑modification state. Those already modified are deemed compliant, but no grace period is given for aircraft that are partly modified , both bulletins must have been implemented. The concept of “later EASA approved revision” is important because it allows the manual to be updated without a new CASA directive, but it also means the operator must monitor EASA approvals to ensure they are using the correct revision.

Finally, the directive makes no provision for economic hardship or alternative schedules. It is a one‑size‑fits‑all requirement with no exception for operators of low‑utilisation aircraft, small businesses, or charter operators. The cost of compliance , potentially removing the partition wall earlier than planned , is borne entirely by the operator, and there is no mechanism for cost recovery or compensation.

The direct targets are the owners and operators of the 30 specific Mystère‑Falcon 900 aeroplanes (serial numbers 188 through 202) and the 65 Falcon 900EX aeroplanes (serial numbers 82 through 146) that have not already incorporated Dassault Modification M3891 or both of the relevant service bulletins. This is a narrow population, likely comprising corporate flight departments, charter operators, and possibly government agencies. Because these are large business jets, the affected parties are typically entities with sophisticated maintenance departments or contracts with approved maintenance organisations. However, smaller operators may exist, particularly in the secondary market where aircraft are purchased by private individuals or small charter companies. For them, the compliance burden is proportionally greater because they may lack in‑house engineering support and must outsource the work.

Beyond the operators, the directive affects several other classes. Maintenance organisations that hold approvals under Part 145 of the Civil Aviation Safety Regulations will need to have the competence and tooling to carry out the inspection, repair, and modification. The work involves accessing the right side partition wall at frames 22/23, which may require removal of interior trim and electrical disconnection. The directive does not specify whether the inspection can be done by the operator’s own licensed maintenance staff or must be performed by an approved organisation, but in practice the repair and modification likely require a repair organisation approval. Parts suppliers and Dassault Aviation itself are also affected, as the service bulletins are the prescribed means of compliance and the AD drives demand for the specified materials (e.g., protective sleeving, replacement feeder cable, and possibly new partition‑wall components).

CASA is the regulator responsible for issuing and enforcing the directive. The AD was signed by a delegate of CASA, James Coyne, on 15 September 2006. CASA’s enforcement arm may conduct audits or investigate reports of non‑compliance. The directive also affects the insurance industry: an operator’s failure to comply with a mandatory AD could void hull or liability insurance cover, or lead to increased premiums. For aircraft lessors or financiers, compliance with airworthiness directives is typically a contractual requirement, so the directive creates a technical condition that must be satisfied to maintain the asset’s value and legal airworthiness.

From an economic perspective, the AD imposes a compliance cost that is fixed per aircraft, with no economies of scale for multiple aircraft unless the same maintenance organisation performs the work on a fleet. The cost includes labour for removal and reinstallation of the partition, possible temporary loss of revenue while the aircraft is grounded for the inspection and corrective action, and parts cost. For an aircraft operated under a commercial air operator’s certificate, the opportunity cost of downtime may exceed the direct maintenance cost. The AD does not offer any alternative compliance method or extension, so the cost is unavoidable for affected aircraft.

The primary duty is on the operator of each affected aeroplane to ensure compliance before the specified deadlines. This duty is non‑delegable: even if the operator contracts the work to an approved maintenance organisation, the operator remains legally responsible for ensuring the aircraft is airworthy and that the AD is fulfilled. The operator must obtain copies of the applicable Dassault Service Bulletins (or later EASA‑approved revisions), arrange for the inspection of the feeder bundle at the right side partition wall (frames 22/23), and, if damage is found, accomplish all applicable corrective actions as specified in the Accomplishment Instructions of the respective bulletin. The operator must also ensure the modification of the partition wall is carried out either at the first removal of the wall or by the later limit of 3,750 flight cycles or 74 months after the effective date. The directive imposes three distinct tasks for each variant, but the first (inspection) and second (corrective action if damage found) are sequential, while the third (modification) is concurrent but with a later deadline.

There is a right to use later EASA‑approved revisions of the service bulletins rather than the original October 2005 versions. This gives the operator some flexibility to adopt improved instructions that may be easier to perform or involve different materials. The operator also has a right to rely on the terminating action statement: once both the inspection bulletin and the modification bulletin have been implemented (or Modification M3891 incorporated), the AD no longer applies to that aircraft, and no further recurring inspections are required under this directive. This is a one‑off duty, not a continuing airworthiness limitation.

The directive does not explicitly grant a right to request an alternative means of compliance or an extension. In the broader regulatory framework (Civil Aviation Safety Regulations Part 39), such rights exist, but the source document does not mention them. Therefore, for the purpose of this deep dive, we cannot assert that an operator has a right to seek an extension under this specific AD, only that the general law may provide that avenue. Similarly, the source does not grant a right to self‑declare compliance without supporting data; the operator must physically perform the inspections and modifications.

A subtle right is implied by the use of “later EASA approved revision”: the operator may have the right to stop using an earlier revision if a later one is approved, but the operator must also ensure it is still using an approved revision. There is no right to use an unapproved revision or a different engineering solution without CASA acceptance. The duty to accomplish corrective actions “before further flight” after a damaged feeder is found is an absolute prohibition on flight unless the repair is completed. This creates a duty on the pilot‑in‑command not to fly an aircraft that has a known non‑compliance with an AD.

For maintenance organisations, the duty is to perform the work in accordance with the service bulletins and to certify the work in the aircraft maintenance records. There is a duty to record the compliance in a manner that shows the AD has been completed, typically by referencing the AD number and the service bulletin revision.

The source document does not itself specify penalties. However, as a CASA‑issued Airworthiness Directive, AD/AMD 50/38 carries the enforcement weight of the Civil Aviation Act 1988 and the Civil Aviation Safety Regulations 1998. Non‑compliance with an AD is a breach of regulation 39.001 of CASR (if applicable) or, more generally, of the condition that an aircraft must maintain its airworthiness in accordance with its type certificate. The aircraft’s certificate of airworthiness is conditional on compliance with all applicable ADs. Therefore, operating an aircraft that has not complied with this directive within the required time constitutes a breach of the certificate of airworthiness. The penalty for operating an aircraft that is not airworthy can include civil penalties (fines) and criminal prosecution in serious cases. Under the Civil Aviation Act, the maximum penalty for an individual could be up to 50 penalty units (currently A$10,000) or imprisonment, and for a body corporate up to 250 penalty units (A$55,000). CASA may also issue enforceable undertakings, suspension or cancellation of the air operator’s certificate, or grounding directions.

Enforcement is typically undertaken by CASA’s Regulatory Services group, which may conduct ramp checks, surveillance audits, or investigate incidents that reveal non‑compliance. The directive became effective on 26 October 2006, so the compliance deadlines have long since passed. For a historical deep dive, the practical enforcement question is whether CASA now treats this AD as closed for aircraft that are still in service. Any aircraft that has not complied by now would be un‑airworthy, and CASA would likely require grounding until compliance is demonstrated. If an operator was found to have falsified records or omitted the AD from a maintenance schedule, they could face enforcement action even years later, as the duty to comply is ongoing until terminated.

The directive also interacts with international obligations: because the aircraft are subject to the Convention on International Civil Aviation, other states’ airworthiness authorities may refuse entry or permit overflight if an aircraft’s AD compliance status is not current. For an aircraft exported or imported, this AD would be part of the required technical records. The source notes that EASA AD 2006‑0270 refers, meaning the European Aviation Safety Agency has an equivalent directive. Non‑compliance with the CASA directive would likely also be non‑compliance with the EASA directive if the aircraft is registered in a state that implements EASA requirements.

For the maintenance organisation, if it certifies compliance without actually performing the work, it faces penalties under Civil Aviation Safety Regulations for making false statements, as well as potential civil liability for negligence if the defect causes damage. Insurance companies may deny coverage for a loss that results from a known non‑compliance, which is an economic penalty separate from any governmental fine.

This directive explicitly references “EASA AD 2006‑0270 refers”, which acknowledges that the European Aviation Safety Agency issued a parallel airworthiness directive covering the same issue. For an aircraft that is registered in a country that adopts EASA ADs (including many European states and some bilateral partners), compliance with the EASA AD is mandatory. If the aircraft is registered in Australia, the CASA AD is the governing directive, but the operator may also need to check whether the EASA AD imposes additional or different requirements, such as a different effective date or compliance options. The source states that implementation of the service bulletins or later EASA approved revision satisfies the CASA directive, which harmonises the two.

The directive also operates within the broader framework of the Civil Aviation Safety Regulations Part 39 (Airworthiness Directives) and Part 21 (Certification of aircraft and parts). Under Part 39, an AD is issued when CASA determines that an unsafe condition exists and is likely to exist or develop in other aircraft of the same type design. This AD therefore interacts with the type certificate data sheet for the Falcon 900 series, and compliance is mandatory to maintain the aircraft’s type conformity. Any modification (like M3891) is a design change that must be approved by the type certificate holder (Dassault) and accepted by CASA; the AD incorporates that modification by reference.

The directive interacts with the aircraft’s approved maintenance program. Typically, an operator’s maintenance schedule is derived from the manufacturer’s recommendations and regulatory requirements. This AD overrides that schedule by inserting a one‑time task that may not have been part of the original maintenance plan. The operator must revise the maintenance program to include this AD, and once completed, may remove it from future scheduled maintenance unless the AD required recurring actions (which it does not). The directive also interacts with other ADs that may affect the same area of the aircraft; for example, if there is an AD on the partition wall itself, the two may need to be coordinated.

From a contract law perspective, this AD becomes part of the conditions under which an aircraft is operated, leased, or sold. A lessor may require the lessee to demonstrate compliance before delivery, and a purchaser may make compliance a condition of sale. The directive also interacts with insurance policies: most aviation insurance policies require the insured to maintain the aircraft in an airworthy condition and comply with all ADs. Failure to do so may void coverage for claims arising from the defect. This creates an economic incentive to comply even in the absence of direct government enforcement.

The directive does not intersect with workplace health and safety laws directly, but the maintenance work involved may require adherence to electrical safety standards and lifting procedures. It does not impact consumer law, trade practices, or competition law. It is a specialised aviation safety regulation with narrow application.

Based solely on the source document, there is no amendment history provided. The directive is presented as a single, original issue dated 15 September 2006, with an effective date of 26 October 2006. The document identifier is AD/AMD 50/38, and the reference number is 11/2006. The source does not contain any later revisions, amendments, or supersedures. The directive states that implementation of the specified service bulletins “or later EASA approved revision” is considered terminating action, indicating that the engineering instructions may be updated by EASA, but the AD itself is not amended by those updates , rather, the operator may use a later revision of the SB without a new directive.

In the broader context (outside the source), it is possible that CASA later issued a superseding directive, revoked this one, or amended it. However, given the requirement to ground all claims in the source, we can only note that the source shows no amendment. The background suggests the manufacturer advised of the discovery of a potential problem, leading to this immediate action. It was likely a one‑off directive, and since the terminating action is permanent once accomplished, there would be little need for an amendment. The directive also does not specify a review period or expiration.

For a deep dive, it is important to note that the absence of amendment history in the source does not mean no amendments exist; but the analyst cannot fabricate them. The reader should be aware that this directive has likely been superseded or is now of historical interest only, given that the compliance deadlines (7 months or 3,750 flight cycles or 74 months from October 2006) have long passed. Any aircraft that remains in service and still complies with this AD would have had to complete the modification years ago.

The source document contains no reference to any litigation, court cases, or legal challenges concerning this Airworthiness Directive. There is no mention of appeals to the Administrative Appeals Tribunal, judicial review proceedings, or prosecutions for non‑compliance. This is not surprising for a narrow, safety‑driven directive affecting a small number of aircraft. Airworthiness directives are rarely challenged in court because they are technical, time‑sensitive, and based on engineering evidence. Operators typically comply because the cost of litigation outweighs the cost of compliance, and the legal grounds for challenging an AD are limited to procedural error or jurisdictional overreach.

It is possible that EASA AD 2006‑0270 (the European equivalent) was the subject of litigation in European courts, but the source does not mention it. Similarly, the manufacturer Dassault Aviation may have faced liability claims related to the chafing issue, but that is not part of this directive. The absence of litigation history in the source means we cannot report any. We can note that the directive was issued under delegated authority from CASA, and any challenge would have to occur within the statutory time limits prescribed by the Administrative Appeals Tribunal Act 1975 or the Judiciary Act 1903. No such challenge is evidenced in the source.

For a practising lawyer, the lack of litigation history is informative , it suggests the directive was implemented without resistance, likely because the population was small and the fix was straightforward. It also means there is no case law interpreting the scope of this AD or the meaning of “later EASA approved revision” in the context of Australian law. Any future disputes would be resolved on the plain wording of the directive and the incorporated service bulletins.

Several aspects of this directive may trap an operator who does not read carefully. First, the compliance deadlines for the initial inspection use “330 hours time in service or seven months after the effective date, whichever occurs first”. The phrase “time in service” is a defined term in aviation regulations, meaning hours flown. An aircraft that flies only 50 hours per year would hit the seven‑month deadline long before the 330‑hour limit. An operator accustomed to complying by hours alone might miss the calendar limit. Conversely, an aircraft that flies 1,000 hours in six months would hit the hour limit first. The operator must track both.

Second, for the modification requirement, the deadline is “at the first time the partition wall is removed, but no later than 3,750 flight cycles or 74 months after from the effective date”. The directive contains a typographical phrase “after from”, but the meaning is clear: the latest absolute limit is 3,750 flight cycles or 74 months after the effective date (26 October 2006). However, if the partition wall is removed earlier for any reason , such as a cabin refurbishment, repair, or other maintenance , the modification must be accomplished at that time, even if the cycle or calendar limit has not been reached. An operator who schedules a partition removal for an unrelated task must be prepared to also carry out the AD‑mandated modification during that downtime, or else they cannot reinstall the wall without being in violation. This could cause schedule disruption and cost if the necessary parts or service bulletin instructions are not on hand.

Third, the directive excludes aircraft on which “Dassault Aviation Service Bulletins (SB) F900-358 and F900-359 both dated 19 October 2005 have both already been implemented or Modification M3891 has already been incorporated.” The key word is “both”. If an aircraft has implemented only the inspection bulletin (F900‑358) but not the modification bulletin (F900‑359), it is still subject to the directive. Similarly, if the operator has done a home‑grown repair that is not exactly M3891, the aircraft is not excluded. The operator must verify that both bulletins have been accomplished per the original October 2005 issue or an approved revision.

Fourth, the corrective actions for damage are required “before further flight after the Requirement 1.a. inspection”. This means if the inspection reveals damage, the aircraft is grounded until the corrective actions are completed. There is no grace period to acquire parts or schedule a maintenance facility. An operator who inspects and finds damage must have the parts and capability ready, or face indefinite grounding.

Fifth, the directive references “latest EASA approved revision” but does not require CASA to approve each revision. The operator must monitor EASA approvals to stay current. If EASA approves a revision that changes the inspection intervals or procedures, the operator must adopt it, because the directive says “or later EASA approved revision”. Using the October 2005 revision after a later revision has been approved may be non‑compliant.

Sixth, the effective date is 26 October 2006, but the directive was published on 15 September 2006. The operator must plan for the first compliance deadline (330 hours or seven months) from that effective date, not from the date of publication. The seven‑month deadline fell around 26 May 2007.

Seventh, the directive does not address record‑keeping beyond the implicit requirement to log the work. An operator who fails to record which revision of the service bulletin was used may have difficulty proving compliance later, especially if the aircraft is sold or leased.

Eighth, the directive applies only to the right side partition wall at frames 22/23. There may be a symmetrical left side that is not covered by this AD; an operator might mistakenly inspect both and waste resources, or fail to realise that the left side is not required. Conversely, an over‑cautious operator might inspect the left side unnecessarily, but that is not a trap.

Compliance with AD/AMD 50/38 involves a series of defined steps, each tied to the applicable aircraft model. For a Mystère‑Falcon 900 (S/N 188‑202) that has not already implemented SB F900‑358 and F900‑359 or Modification M3891, the operator must:

1. Obtain a copy of Dassault Service Bulletin F900‑358 (or a later EASA‑approved revision). This bulletin contains the inspection and protection instructions for the feeder from the right side partition wall at frames 22/23. The operator must perform the inspection within 330 hours time in service or seven months after 26 October 2006, whichever occurs first. This is a one‑time inspection; no recurrence is required unless the bulletin says otherwise.

2. During the inspection, if the feeder is found damaged (e.g., chafing, abrasion, evidence of arcing), the operator must immediately accomplish all applicable corrective actions specified in the Accomplishment Instructions of SB F900‑359 (or later EASA‑approved revision). This corrective action is required “before further flight” , meaning the aircraft cannot be flown again until the repair is completed. The corrective actions likely involve repairing or replacing the feeder cable and protecting it from future contact with the partition wall.

3. Regardless of whether damage is found, the operator must modify the right side partition wall at frames 22/23 and protect and/or repair the feeder cable as instructed in SB F900‑359. This modification must be done at the first time the partition wall is removed for any reason, but no later than 3,750 flight cycles or 74 months after 26 October 2006. If the partition wall has never been removed, the operator must plan a specific removal to accomplish this task before the later limit. After the modification, the AC can also include any additional repairs needed if damage was found.

4. Record the compliance in the aircraft maintenance records. The record should include the AD number, the service bulletins used (including revision dates), the date of inspection, any damage found and corrective actions taken, and the date of the partition wall modification. This record is evidence of terminating action.

For a Falcon 900EX (S/N 82‑146), the process is identical in structure but uses SB F900EX‑241 (inspection) and SB F900EX‑251 (modification/corrective actions). The compliance deadlines are the same: initial inspection within 330 hours TIS or 7 months; corrective actions before further flight if damage found; modification at first partition wall removal or by 3,750 cycles or 74 months.

The operator must ensure that the maintenance organisation performing the work has the capability to access frames 22/23 on the right side, which may require removal of cabin interior panels and electrical connectors. The operator should coordinate with the maintenance provider to order any necessary parts (e.g., protective sleeving, feeder cable, possibly a new partition wall panel) well before the deadline.

If the operator has already incorporated Modification M3891 at any time before the effective date, no further action is required under this directive. If the operator has only partially implemented the service bulletins, they must complete the missing bulletin(s).

Finally, the operator should check whether any later EASA‑approved revision has superseded the October 2005 bulletins. If so, the later revision must be used for compliance. The operator can confirm current revision status through Dassault Aviation’s customer portal or through EASA’s website. Failure to use the latest approved revision could render the compliance non‑standard and potentially unacceptable in an audit.

After all steps are verified and recorded, the AD is considered closed for that aircraft. The operator should note the compliance in the aircraft’s continuing airworthiness record system, such as a logbook entry or electronic maintenance tracking system, and retain the service bulletins and work orders as supporting documents.