AD/AMD 50/34 - Ice and Rain Protection - Outboard Leading Edge Slats

The AD rests on three main technical and regulatory concepts set out in its text: (1) model interchangeability and functional equivalence, (2) identification and corrective action for incorrect parts and systems, and (3) staged compliance with terminating actions.

First, the AD highlights that although outboard slats are aerodynamically and mechanically interchangeable across several Dassault models, the hot air anti‑icing systems are not equivalent between MF50 and MF900/F900EX (and the F2000 series, which is noted in the background). The AD states that the wings are "aerodynamically identical on many points" and that "outboard slats on all 5 models have the same external shape and are mechanically interchangeable", while adding that the anti‑icing systems differ so the slats are "functionally not equivalent". This distinction is the technical trigger for the AD because interchange or repair actions could alter an aeroplane’s anti‑icing performance.

Second, the AD treats incorrect installation of slats or anti‑icing manifolds as the risk to be mitigated. It points to misleading identification plates on slats and to authorised interchangeability having been "erroneously authorized in some limited cases". The AD therefore imposes an inspection requirement to check slat type and mandates corrective steps where discrepancies exist: temporary AFM changes for MF50 pending manifold replacement, and manifold repair actions for MF900 and F900EX. It names specific manufacturer documents to perform inspections and repairs (F50‑475, F900‑370, F900EX‑273, SB F50‑478), making those documents normative for compliance.

Third, the AD implements a staged compliance framework with terminating actions. The inspection has an initial compliance window (330 flight hours or 7 months). Where incorrect slats are found, interim mitigations (AFM temporary change) may be required before a terminating repair is completed. For MF50, replacing the anti‑icing manifold per SB F50‑478 is stated to be the terminating action; the AFM temporary change may be removed thereafter. For MF900 and F900EX, repairing the manifold per F900‑370 or F900EX‑273 is stated to be a terminating action. The AD explicitly labels these repairs as terminating actions for the AD for the relevant aircraft.

The AD also cross‑references other regulatory material by noting that EASA AD 2006‑0037 (1 February 2006) is referred to. The background paragraph explains the factual basis for the AD: interchangeability errors and misleading parts plates may have led to installation of slats or manifolds "of the type not adapted to the aircraft model", which "may jeopardize the aircraft, by modifying its anti‑icing performance". That statement frames the safety rationale the AD seeks to remedy.

The AD explicitly applies to specific serial number ranges of Dassault aircraft. The "Applicability" table lists affected airframes as: Mystere‑Falcon 50 aircraft serial numbers 2 to 344; Mystere‑Falcon 900 aircraft serial numbers 1 to 202; and Falcon 900EX aircraft serial numbers 1 to 96 and 98 to 154. Those serial number ranges define the population of aircraft to which the AD’s inspection and corrective requirements apply.

Practically, the AD affects the aircraft operators (airlines, corporate operators, leasing companies) that hold these airframes on their Australian registry or otherwise operate them under the jurisdiction of the issuing authority. It also affects maintenance organisations and engineers responsible for performing the inspections, AFM temporary changes, manifold replacements or repairs, and for recording compliance. The AD mandates actions to be performed "in accordance with the instructions detailed in" the specified manufacturer documents, so organisations that control maintenance data and parts supply must have access to F50‑475, F900‑370, F900EX‑273 and SB F50‑478.

The AD places immediate obligations on operators when incorrect slats are discovered. For MF50 aircraft with incorrect slats, it requires insertion of an AFM Temporary Change No 61 (AFM reference DTM813 or DTM803) or TC No 75 (AFM reference FM813EX) and replacement of the anti‑icing manifold according to SB F50‑478. The AFM TC is an operational limitation or temporary procedure that must be inserted into the AFM and is explicitly permitted to be removed only after the replacement is carried out. For MF900 and F900EX aircraft found to have incorrect slats, the AD requires repair of the manifold per model‑specific instructions; that repair is expressly defined as the terminating action for the AD for those aircraft.

Maintenance control organisations must also deal with parts identification issues that the background highlights. The AD states that the slat part‑number identification plates "appear to be misleading" and that earlier authorisations permitted interchangeability "erroneously" in some cases. That means organisations involved in parts management, logbooks and historical records must check whether slats were exchanged after delivery or whether repairs might have fitted manifolds "not adapted to the aircraft model". Where such exchanges are found, the AD’s repair and AFM TC requirements apply.

The AD notices EASA AD 2006‑0037 as a related instrument, which may be relevant to operators with cross‑jurisdictional operations or maintenance performed under EASA oversight. The AD does not list any exemptions, nor does it set out alternative compliance paths; it prescribes specific inspection and corrective actions for the listed serial numbers.

The AD creates specific duties for operators and maintainers of the affected aircraft. Those duties are set out as numbered Requirements in the AD. Operators must:

• Carry out an inspection of the outboard slats "in accordance with the instructions detailed in F50‑475, F900‑370, or F900EX‑273 as is applicable" (Requirement 1). The compliance time for this inspection is "within 330 Flight Hours (FH) or 7 months, whichever comes first, following the effective date of this AD."

• For MF50 aircraft found to have incorrect slats, insert into the Aeroplane Flight Manual a Temporary Change (TC) No 61 (AFM reference DTM813 or DTM803) or TC No 75 (AFM reference FM813EX) and replace the anti‑icing manifold "according to the instructions in SB F50‑478" (Requirement 2 parts (a) and (b)). The AD states that the AFM TC may be removed after carrying out the manifold replacement, which the AD identifies as "a terminating action for this AD for MF50 aircraft." The compliance timing is split: 2(a) must be done "before further flight" and 2(b) must be done "within 1530 FH following the inspection detailed in Requirement 1."

• For MF900 and F900EX aircraft with incorrect slats, repair the manifold "according to the instructions detailed in F900‑370, or F900EX‑273 as is applicable" (Requirement 3). The AD states explicitly that this repair "is a terminating action for this AD for the relevant aircraft." The compliance entry for Requirement 3 in the AD lists "Before further flight."

These duties impose both immediate and medium‑term obligations: some actions are required before the aircraft may return to flight, and others must be completed within a stated flight‑hour window. The AD identifies the documents and service information that must be used to carry out inspections and repairs; compliance requires access to and adherence to those manufacturer instructions.

The AD also implicitly creates rights relevant to the operator’s compliance posture. It allows removal of the AFM Temporary Change once the terminating action (manifold replacement on MF50) has been carried out, effectively restoring the AFM to its prior state after corrective maintenance. The AD does not specify any alternative methods of compliance or rights to deviate from the prescribed instructions. It cross‑references EASA AD 2006‑0037, which may be consulted for additional information but the AD itself makes the cited manufacturer documents the basis for compliance.

The AD does not set out appeals, review processes, or grace periods beyond the specified compliance windows. It uses the phrase "This is a terminating action for this AD" to indicate completion of the AD’s obligations for that aircraft once the stated repair or replacement is performed. Operators must therefore plan to both perform and to document the actions so that the AD’s requirements can be demonstrated to inspectors or regulators.

The text of the AD does not specify civil or criminal penalties, nor does it set out enforcement procedures in statutory detail. The instrument is presented as an Airworthiness Directive from CASA, dated 17 March 2006 and effective 11 May 2006, signed by James Coyne, Delegate of the Civil Aviation Safety Authority. As issued, the AD prescribes mandatory inspection and corrective work within defined time frames for the listed aircraft serial numbers.

Because the AD itself does not include penalty provisions, enforcement will be through the usual aviation regulatory channels used by CASA for airworthiness directives. The AD makes compliance timeframes and terminating actions explicit; failure to comply with the AD would leave an operator without the AD‑required corrective actions recorded, which in practice can affect continued validity of the aircraft’s airworthiness under CASA oversight. The AD requires insertion of AFM Temporary Changes where specified and records of repair or replacement actions per the referenced service information. Those are steps that CASA or its delegates would normally verify during surveillance, certification or continued airworthiness oversight activities.

The AD also cross‑refers EASA AD 2006‑0037. While the AD itself does not set out enforcement sanctions, non‑compliance with an AD typically exposes an operator to regulatory enforcement action available under the relevant aviation safety legislation, including potential grounding, prohibition from flight, administrative penalties or other corrective enforcement measures. None of those enforcement options are described in the AD’s text.

The AD’s compliance requirements include explicit "before further flight" instructions for certain corrective steps, which operationally mean that unless the required action is completed the aircraft should not be flown. The AD does not describe exceptions, extensions or alternative means of compliance. Practitioners should interpret the AD as creating mandatory duties to inspect and correct in the timeframes given and should expect that CASA will treat an operator’s failure to comply as a matter for its enforcement processes, which sit outside the AD’s text.

The AD references external technical and regulatory materials that become relevant to compliance. It explicitly refers to manufacturer service instructions and AFM Temporary Changes: inspections are to be done "in accordance with the instructions detailed in F50‑475, F900‑370, or F900EX‑273", and replacement or repair actions reference SB F50‑478, F900‑370 and F900EX‑273. Those documents form the technical basis for compliance and, in regulatory practice, are incorporated by reference by the AD. Operators therefore must follow the content of those manufacturer documents in addition to the AD itself.

The AD also notes EASA AD 2006‑0037 dated 1 February 2006. That cross‑reference indicates parallel regulatory action by a European aviation authority and may have implications where aircraft are operated, maintained or registered across jurisdictions. The AD does not reproduce EASA’s text, but by referencing it the AD signals that operators may need to consider both CASA and EASA instruments where applicable.

The AD requires insertion and possible later removal of Temporary Changes to the Aeroplane Flight Manual (AFM). AFM content and any temporary changes are matters that interface with regulatory requirements for operations and documentation; an AFM change will alter the operator’s operational limitations and procedures until a terminating action is completed. The AD makes the AFM TC an interim operational control for MF50 aircraft with incorrect slats, and permits removal of the TC only after the manifold replacement constituting the terminating action is carried out. This creates an interaction between maintenance obligations and operational approval documentation.

Although the AD mentions F2000 and F2000EX aeroplanes in its background as sharing aerodynamically identical wings, the Applicability section does not list those models. That creates a potential interaction issue for operators or maintenance organisations that handle multiple Dassault types: the background observations may be relevant to parts interchange or maintenance carried out under other regulatory approvals, but the AD’s enforceable scope is limited to the serial numbers listed.

The AD does not specify other legislation (for example, specific sections of the Civil Aviation Act or regulations) or provide a procedural avenue for alternative methods of compliance. Therefore practitioners should treat the AD and the referenced manufacturer documents as the operative compliance instruments and consider any broader regulatory requirements for maintenance approvals, recordkeeping and airworthiness certification as applying in the ordinary way under CASA oversight.

The AD text supplied includes the AD designation "AD/AMD 50/34" and a date code "5/2006". The document is signed by James Coyne, Delegate of the Civil Aviation Safety Authority, and dated 17 March 2006. The AD is stated to become effective on 11 May 2006. The only explicit external document referenced for amendment or correspondence is EASA AD 2006‑0037 dated 1 February 2006.

The AD itself does not include a history of prior amendments, earlier versions, supersessions, or later revisions within the supplied text. There are no listed revocation clauses or schedules of previous AD numbers changing this AD, nor are there any footnotes indicating that earlier ADs have been amended by this instrument. The AD’s internal numbering of Requirements 1, 2 and 3 constitutes the operative structure; but no later amendment or corrigendum is shown.

Where the AD mentions that the AFM Temporary Change "may be removed after carrying out the actions detailed in requirement 2(b) of this AD", that constitutes an internal conditional amendment of AFM content tied to completion of the terminating action. However, that is a compliance conditionality rather than an amendment of the AD itself.

Because the supplied text does not include any explicit amendment entries, practitioners seeking any subsequent amendments, revocations or clarifying notices must consult CASA’s official AD database or consult EASA AD 2006‑0037 for related actions. The AD’s effective date (11 May 2006) and the signature date (17 March 2006) are the only temporal markers for the instrument in the text provided.

The supplied text of the AD contains no information about litigation, appeals, judicial review or enforcement actions arising from the AD. It does not record any challenges, court proceedings, administrative appeals, or decisions interpreting the AD’s requirements. The document is an administrative directive from CASA and is presented without any accompanying litigation record.

Because the AD itself is a regulatory measure, any disputes about its validity, interpretation, or application would be pursued through the relevant administrative and judicial channels available under aviation law and administrative law. The AD does not describe any such channels or report outcomes of previous litigation. The only legal or regulatory cross‑reference in the text is to EASA AD 2006‑0037 dated 1 February 2006; that cross‑reference is technical and regulatory, not a litigation history.

Practitioners requiring information about whether this AD has been subject to legal challenge, or whether there have been enforcement actions that generated case law, must consult court records, CASA enforcement notices, or legal databases. None of that material is included in the text provided.

Several potential practical pitfalls arise from the AD text that operators, maintenance organisations and regulators should note.

• Parts identification plates may be misleading. The AD states that "The outboard slats P/N identification plates also appear to be misleading." That increases the risk of misidentification during inspection. Relying solely on visible P/N plates could lead to false negatives or positives; inspectors should follow the AD’s referenced inspection instructions in F50‑475, F900‑370 or F900EX‑273 rather than relying only on plate markings.

• Interchangeability was "erroneously authorized" in some limited cases. The AD’s background notes that interchangeability between MF50 and MF900/F900EX or F2000/F2000EX had been erroneously authorised. Where maintenance logs show parts swaps or post‑delivery exchanges, operators must treat those aircraft as potentially non‑conforming until the inspection confirms correct slat/manifold type.

• Scope versus background mismatch. The background discusses F2000 and F2000EX aeroplanes as sharing wing characteristics, but the Applicability table lists only Mystere‑Falcon 50, Mystere‑Falcon 900 and Falcon 900EX serial numbers. Maintenance organisations responsible for F2000 models should not assume the AD’s requirements automatically apply to those airframes; conversely, the background comment indicates a latent risk that could be relevant outside the AD’s stated applicability and thus warrants checking maintenance history for similar issues on related types.

• Timing complexity. The AD imposes mixed timing obligations: an initial inspection within 330 FH or 7 months; AFM Temporary Changes "before further flight" in certain circumstances; replacing the manifold for MF50 within 1 530 FH after inspection; and manifold repair for MF900/F900EX "before further flight". Practitioners must track both calendar and flight‑hour metrics to ensure compliance. A slip on the "before further flight" requirement in particular may create regulatory exposure because it is operationally limiting.

• Removal of the AFM TC conditional. For MF50 aircraft, the AFM Temporary Change can only be removed after the replacement action in Requirement 2(b) is completed. That creates a compliance sequencing requirement: operators must ensure the AFM TC remains in effect until the terminating manifold replacement is fully documented.

• Terminating action differs by model. The AD specifies different terminating actions depending on the model: for MF50 the manifold replacement per SB F50‑478; for MF900 and F900EX the manifold repair per F900‑370 or F900EX‑273. Applying the wrong service bulletin or the wrong model’s repair procedure could leave the operator non‑compliant despite having performed maintenance.

• Documentation and parts traceability. Given the background about erroneous authorisation and misleading plates, inspectors and maintainers must seek historical records of slat exchanges, repairs and manifold installations. Incomplete or imprecise records will complicate proving compliance.

• Cross‑reference to EASA AD. The AD refers to EASA AD 2006‑0037. Operators with multi‑jurisdictional operations must check whether that EASA AD imposes additional or differing requirements.

• Text formatting and clarity issues. The supplied AD text reproduces some duplicated headings and isolated lines such as "3. Before further flight." Practitioners should consult the original published AD in CASA’s database or the EASA reference to clarify any ambiguity arising from formatting, rather than relying on a possibly garbled reproduction.

The AD states explicit steps and timeframes. A compliant sequence based on the AD text is as follows.

1. Identify applicability. Confirm whether each aircraft is within the serial number ranges listed: Mystere‑Falcon 50 S/N 2 to 344, Mystere‑Falcon 900 S/N 1 to 202, Falcon 900EX S/N 1 to 96 and 98 to 154. If an airframe is not in these ranges, the AD as issued does not list it as applicable, though the background suggests vigilance on related models.

2. Schedule and perform the required inspection. Within 330 flight hours or 7 months from the AD’s effective date (whichever comes first), perform the outboard slat inspection "in accordance with the instructions detailed in F50‑475, F900‑370, or F900EX‑273 as is applicable" (Requirement 1). Ensure maintenance staff have the correct and current versions of those documents.

3. If incorrect slats are found on MF50 aircraft:

   • Before further flight, insert the appropriate Aeroplane Flight Manual Temporary Change into the AFM: TC No 61 (AFM reference DTM813 or DTM803) or TC No 75 (AFM reference FM813EX) as specified in Requirement 2(a). This AFM TC is an interim operational control.
   • Replace the anti‑icing manifold "according to the instructions in SB F50‑478" (Requirement 2(b)). The AD permits removal of the AFM TC only after this manifold replacement has been completed. Requirement 2(b) must be completed within 1 530 flight hours following the inspection detailed in Requirement 1.

4. If incorrect slats are found on MF900 or F900EX aircraft:

   • Repair the manifold "according to the instructions detailed in F900‑370, or F900EX‑273 as is applicable" (Requirement 3). The AD states this repair is a terminating action. The compliance entry for Requirement 3 is "Before further flight", so the manifold repair must be completed prior to returning the aircraft to service.

5. Recordkeeping and AFM updates. Document the inspection findings, the insertion of any AFM Temporary Change, the repair or replacement work performed and the removal of the AFM TC once the terminating action has been completed. Maintain copies of the referenced service bulletins and workpack approvals used to perform the actions. The AD makes these steps determinative of compliance.

6. Use the prescribed service information. The AD makes manufacturer documents normative: F50‑475, F900‑370, F900EX‑273 for inspection, SB F50‑478 for manifold replacement on MF50, and F900‑370/F900EX‑273 for manifold repair on MF900/F900EX. Do not substitute procedures unless an approved alternative method of compliance is obtained from the regulator.

7. Cross‑check maintenance history. Because the AD identifies misleading P/N plates and prior erroneous authorisation of interchangeability, review logbooks and parts records to ascertain whether slat or manifold exchanges or repairs have occurred after delivery. Where records are incomplete, treat the aircraft as potentially affected until inspection confirms correct parts.

8. Consult CASA or manufacturer if unclear. If there is ambiguity about which document applies, or if the inspection reveals complex discrepancies, seek clarification from CASA or the manufacturer. The AD references EASA AD 2006‑0037; consult that instrument for related guidance, particularly for aircraft maintained or certified under EASA procedures.

9. Plan operational impacts. For MF50 aircraft that require an AFM TC, operators must implement the TC into operational documentation and brief crews on the temporary procedures or limitations, until the terminating manifold replacement is complete and the TC can be removed.

10. Verify termination. After completing the specified repair or replacement (the AD’s terminating action), verify that all records are updated and the AFM TC is removed where permitted. Retain documentation demonstrating that the terminating action was performed per the specified service instructions, as evidence of compliance.

Following the AD’s explicit instructions, adhering to the cited service documents, and maintaining clear records will satisfy the instrument’s operational and maintenance requirements. If there is any doubt arising from the reproduced formatting or text ambiguities in this version of the AD, consult the original CASA AD notice and the referenced EASA AD for authoritative detail.