AD/F50/94 - Engine Mount Tubing and End Fittings

The AD is focused on detection, reporting and control of internal corrosion in engine mount tubing and end fittings on specified Fokker F50 series aeroplanes. The principal conceptual elements in the document are:

• Inspection mandate and standardisation: The AD prescribes a specific non‑destructive inspection technique (X‑ray) and ties that technique to the accomplishment instructions in a named Fokker Service Bulletin (SBF50-71-047, Section 3). By reference to those instructions the AD standardises the method, scope and likely acceptance criteria (as defined in the bulletin), and requires that any later revisions used be approved by EASA. The inspection mandate is a one‑time mandated action with a fixed compliance window (within two years after 8 June 2006), not an ongoing interval specified in the AD text.
• Reporting obligation: The AD mandates reporting of inspection results to Fokker Services, and prescribes the reporting procedure as set out in the same service bulletin. The reporting requirement is time‑bound (within seven days of completing the inspection). This creates a data flow from operators to the manufacturer (Fokker).
• Spare part control: The AD prohibits the installation of spare engine mounts on any aircraft unless the spare has itself been X‑rayed in accordance with a specific Fokker Component Service Bulletin (F8200-035-71-12), again with an allowance for later EASA‑approved revisions. The prohibition takes effect after 15 June 2006.
• Scope and exception: The applicability is model‑based (F27 Mk 050, Mk 0502, Mk 0604), all serial numbers, subject to the exception that aircraft whose engine mount frames have already been inspected in accordance with MRB Document Task Numbers 712000-00-09 and 712000-00-10 are excluded. That creates a record‑based exemption: previous compliance under specific MRB tasks removes the requirement.
• Regulatory back‑reference to external approvals and foreign AD: The AD requires that the referenced service bulletins used be either the dated versions (15 February 2006) or later revisions that are EASA approved, and it notes a corresponding CAA‑NL (Netherlands) AD NL‑2006‑005. This anchors the AD in a network of manufacturer guidance and European authority approvals.
• Stated technical rationale: The AD includes a brief causal claim that synthetic preservation oil film degradation is considered the cause of the observed internal corrosion, and notes the safety consequence being the potential for engine mounting frame failure if multiple tubes are severely affected.

These concepts combine to produce three mechanisms: detection (X‑ray inspects), information aggregation (reporting to Fokker), and hazard control (preventing uninspected spares being fitted). The AD delegates the technical detail of how to inspect and how to report to the manufacturer’s service bulletins, and it conditions acceptable methods on EASA approval of any later revisions. The AD sets specific, time‑limited obligations rather than an ongoing inspection regime.

The AD identifies a narrow set of regulated parties and reporting recipients. The affected groups in the document are:

• Operators and owners of Fokker F50 aeroplanes of the listed models: The AD applies to Model F27 Mk 050, Mk 0502 and Mk 0604 aircraft, all serial numbers, subject only to the exception where engine mount frames have already been inspected under MRB Document Task Numbers 712000-00-09 and 712000-00-10. Therefore the primary burden is on operators and owners of those aircraft for which the MRB inspection exception does not apply.
• Maintenance organisations and engineers carrying out inspections: The AD requires an X‑ray inspection in accordance with the manufacturer’s service bulletin instructions. That task will be carried out by licensed maintenance organisations or personnel authorised to perform non‑destructive testing and component inspection for these aircraft. The AD indirectly affects them by specifying the inspection technique and the manufacturer instructions that must be followed.
• Suppliers and holders of spare engine mount assemblies: The AD prohibits the installation of spare engine mounts unless the spare has been X‑rayed in accordance with Fokker Component Service Bulletin F8200-035-71-12 (or later EASA approved revision). Holders of spare parts (maintenance providers, spares pools, lessors, repair shops) are therefore subject to an inspection requirement prior to installation.
• Fokker Services as the reporting recipient: Requirement 2 requires reporting all inspection results to Fokker Services, using the procedure in SBF50-71-047. The AD therefore creates a mandatory information stream to the manufacturer.
• Regulatory authority and its delegate: The AD is issued by a delegate of the Civil Aviation Safety Authority (signed by Richard Castles). While the AD does not list enforcement agencies or penalties within its text, it is an instrument issued by the regulator and therefore imposes regulatory duties on the above parties.

Parties not explicitly named but indirectly implicated include lessees, aircraft managers and insurers which may be affected by grounding or maintenance scheduling arising from inspections, because the AD requires actions that can affect aircraft availability. The AD also references EASA approval of later service‑bulletin revisions and a CAA‑NL AD (NL‑2006‑005); this links the operator’s obligations to approvals and directives maintained by other entities. The document does not specify any exemptions based on operation type or geographic region; applicability is expressed by aircraft model and serial number, and by the saved‑exemption for prior MRB inspections. The AD does not set out a process for seeking alternate means of compliance within the text; it only prescribes the service bulletins and EASA approval standard for later revisions.

The AD imposes three duties and creates one negative right (a prohibition). All of these are set out in the Requirements section and compliance timetable.

Duties

1. Duty to inspect (Requirement 1): Operators must "perform an X‑ray inspection on the engine mount tubing and end fittings in accordance with Section 3. Accomplishment Instructions of Fokker Service Bulletin SBF50-71-047, dated 15 February 2006, or later EASA approved revision." This duty is time‑limited: the inspection must be completed within two years after 8 June 2006. The AD makes the service bulletin instructions normative by reference.

2. Duty to report (Requirement 2): Following completion of the inspection required by Requirement 1, operators must "report all inspection results to Fokker Services in accordance with the procedure described in SBF50-71-047." The reporting timeframe is seven days after accomplishment of the inspection. The duty thus requires not only conducting the inspection but also timely transmission of results to Fokker using the bulletin’s prescribed procedure.

3. Duty to ensure spare parts inspection before installation (embedded in Requirement 3): Operators and maintenance organisations must ensure that any spare engine mount intended for installation has itself been X‑ray inspected per Section 3 Accomplishment Instructions of Fokker Component Service Bulletin F8200-035-71-12, dated 15 February 2006, or a later EASA‑approved revision. That duty effectively requires maintenance organisations to control inventory and to verify the inspection status of spares prior to installation. The effective date for that prohibition is "after 15 June 2006."

Negative right / prohibition

• Prohibition on installing uninspected spare engine mounts (Requirement 3): The AD states "No spare engine mount may be installed on any aircraft as a replacement part, unless it has been X‑ray inspected in accordance with Section 3. Accomplishment Instructions of Fokker Component Service Bulletin F8200-035-71-12, dated 15 February 2006, or later EASA approved revision." This creates a ban on installing spares that have not been X‑ray inspected according to the referenced bulletin; the ban takes effect after 15 June 2006.

Rights and exceptions

• Applicability exception: The AD exempts aircraft whose engine mount frames "have been inspected previously in accordance with the Fokker 50/60 MRB Document, Task Numbers 712000-00-09 and 712000-00-10." That creates a right to not perform the AD obligations where earlier MRB inspections, executed to those task numbers, have already been completed and recorded. The operator bears the burden of demonstrating that the prior MRB tasks were performed to claim the exemption.

Standards for acceptable documentation and methods

• The AD requires the use of the named service bulletins and permits the use of later revisions only where they are "EASA approved." Thus, operators must ensure the specific edition of the service bulletin used is either the dated version named in the AD (15 February 2006) or an EASA‑approved later revision. The AD itself does not provide alternative acceptance criteria or an alternate means of compliance within its text.

Timing and notification

• The AD becomes effective on 8 June 2006; the inspection window is within two years after that date; reporting must occur within seven days of inspection; and the spare‑part prohibition is effective after 15 June 2006.

The AD does not specify mechanisms for seeking extensions, relief, or alternative compliance paths within its text. It does not specify record retention periods, nor does it set out administrative processes for demonstrating compliance beyond the reporting requirement to Fokker Services.

The AD text itself contains no penalty clauses, monetary fines, or explicit enforcement procedures. The document is an Airworthiness Directive issued by a delegate of the Civil Aviation Safety Authority (signed "Richard Castles, Delegate of the Civil Aviation Safety Authority", dated 18 April 2006), and it becomes effective on 8 June 2006. The AD sets mandatory technical duties and a prohibition, but it does not include within its text any of the following: specific sanctions for non‑compliance, procedural details for enforcement action, or references to civil or criminal penalty provisions.

Because the AD is a regulatory instrument issued by the aviation regulator (the AD header and signature identify the regulator’s delegate), it functions as a binding directive under the regulator’s authority; however, the AD document does not itself list enforcement powers or the mechanisms by which compliance will be monitored or action taken against non‑compliant parties. The AD does require reporting of inspection results to Fokker Services within seven days, which establishes a reporting trigger that could, in practice, be used to identify non‑compliance if reports are absent, but the AD does not state that directly.

The AD does reference EASA approval for later revisions of the referenced service bulletins and notes a corresponding Netherlands AD (CAA‑NL AD NL‑2006‑005); beyond those references the AD contains no litigation, penalty, or enforcement history. In this document there is therefore no textual authority to describe sanctions or enforcement procedures; the AD only imposes the technical and reporting duties and sets deadlines.

Practically, parties reading the AD should note two things from the text: (1) the AD is issued by the aviation regulator (via its delegate), and (2) it contains a reporting requirement that creates a documented interaction with the manufacturer. The AD leaves unspecified in its text how the regulator will audit, verify or enforce compliance, and it does not itself set out penalty provisions, so anyone requiring clarity about enforcement would need to consult the regulator or the broader regulatory framework outside the AD text.

The AD makes explicit cross‑references to manufacturer service bulletins and to a foreign airworthiness directive; these are the only inter‑instrument references contained in the text.

References in the AD

• Manufacturer service bulletins: The AD requires compliance with Section 3, Accomplishment Instructions, of Fokker Service Bulletin SBF50-71-047 (dated 15 February 2006) for the required X‑ray inspection, and with Section 3 of Fokker Component Service Bulletin F8200-035-71-12 (dated 15 February 2006) for inspection of spare engine mounts. The AD allows later revisions of those service bulletins to be used only if the later revisions are EASA approved. Thus the AD imports technical detail and procedural instructions from the manufacturer’s service bulletins and conditions their acceptability on external approval by EASA.

• EASA approval: The AD repeatedly conditions acceptance of any later service bulletin revisions on EASA approval ("or later EASA approved revision"). This embeds the AD in an approval chain where the technical conforming documents are validated by EASA before they may be relied on for compliance with the AD.

• CAA‑NL AD NL‑2006‑005: The AD notes that "CAA‑NL AD NL‑2006‑005 refers." That shows the AD is linked to a corresponding Netherlands authority directive and therefore sits in a set of international airworthiness directives and responses to a shared technical problem.

Interactions implied by the AD text

• Manufacturer‑driven compliance: By mandating the use of specific manufacturer service bulletins and the reporting of results to Fokker Services, the AD channels compliance activity through manufacturer‑produced documents. The AD does not itself create the inspection procedure; rather, it makes compliance with the manufacturer’s procedures mandatory. The AD therefore creates an interaction where the regulator’s requirement is implemented via manufacturer documentation and EASA approvals.

• Record and proof of prior MRB inspections: The AD exempts aircraft where engine mount frames "have been inspected previously in accordance with the Fokker 50/60 MRB Document, Task Numbers 712000-00-09 and 712000-00-10." That creates a documentary interaction: operators must be able to demonstrate that prior MRB tasks were completed to claim the exemption. The AD does not specify the acceptable documentary proof, but the exemption ties the AD’s applicability to previous compliance with manufacturer MRB tasks.

Limits of what the AD says about law interactions

• The AD does not reference specific domestic legislative provisions, criminal or civil penalties, or administrative enforcement statutes within its text. Nor does it provide a process for seeking an alternative means of compliance within the AD itself. The only approvals and external authorisations mentioned are EASA approvals of service bulletin revisions and the noted CAA‑NL AD.

• The AD does not set storage, record retention, or reporting confidentiality standards, nor does it create obligations under other statutes that are explicit in the text. Any such interactions (for example with broader aviation safety legislation, customs or trade rules for spare parts, or data protection rules for reporting) are not referenced in the AD, and would require consultation of those regimes outside the AD’s text.

In short, the AD integrates with manufacturer documentation and EASA approvals, and it references a comparable foreign AD, but it does not itself cite or specify procedural interactions with domestic enforcement statutes or other laws beyond the service‑bulletin/EASA/CAA‑NL network.

The AD document contains only the following temporal data and no internal amendment log. The AD itself appears as AD/F50/94, dated 6/2006 in the header. The specific dates and sequencing provided in the AD are:

• Fokker Service Bulletin and Component Service Bulletin dates: Both SBF50-71-047 and F8200-035-71-12 are named with the date 15 February 2006. The AD permits later revisions of those bulletins only if the later revisions are approved by EASA.
• Signature and issuance: The AD includes a signature block naming "Richard Castles, Delegate of the Civil Aviation Safety Authority" and is dated 18 April 2006 in the signature block.
• Effective date: The AD states explicitly "This Airworthiness Directive becomes effective on 8 June 2006."
• Compliance windows: The AD specifies compliance timing relative to the effective date: the X‑ray inspection (Requirement 1) must be completed "within 2 years after 8 June 2006"; reporting (Requirement 2) must be completed "within 7 days of accomplishment of Requirement 1 inspection"; the spare spare‑mount prohibition (Requirement 3) is effective "after 15 June 2006."

The AD does not contain any entries describing amendments to the AD itself, nor does it include prior AD numbers that it supersedes or is superseded by. There is no textual indication in the provided document of any later amendments, revocations, or replacement ADs. The AD does not list a registry or history section showing prior or subsequent changes.

The AD does cross‑reference a related foreign AD (CAA‑NL AD NL‑2006‑005) via a note, but it does not document whether that foreign AD predates or postdates this AD, nor does it record any consequential amendments that arose after issuance. The only amendment‑like control in the AD is the allowance for "later EASA approved revision" of the referenced Fokker service bulletins; that phrase is a rolling gateway permitting operators to use newer, EASA‑approved versions of the instructions without the AD needing to be reissued, but the AD itself provides no schedule or list of such later approved revisions.

Therefore, within the text available, the AD has the issuance, effective and compliance dates listed above and no recorded amendment history. Any inquiry about subsequent amendments, supersession, or revocation would require consultation of the regulator’s AD database or other official records outside this single AD text.

The AD document does not include any litigation history, nor does it refer to any judicial decisions, proceedings, or disputes. The AD names no cases, contains no references to litigation, and does not claim to be the subject of judicial review or challenge within its text.

The AD is a regulatory directive issued by a delegate of the Civil Aviation Safety Authority (signed by Richard Castles and dated 18 April 2006). The document contains factual background about the technical problem (internal corrosion discovered during MRB mid‑life X‑ray inspections) and imposes inspection and reporting duties, but it does not recount any enforcement actions, administrative proceedings, adjudications, court rulings, or litigation that arose from the AD. There is therefore no litigation history recorded in this instrument.

If a reader requires whether the AD has been the subject of legal challenge, referenced in case law, or has generated disputes involving operators, manufacturers or regulators, the AD text provides none of that material and does not authorise any conclusions about litigation. Such information would have to be sought from external sources , for example, court records, administrative tribunal files, or regulator archives , which are not part of this AD document.

The AD text contains several specific features and potential traps for operators, maintainers and parts‑holders. The features that create risk of non‑compliance or operational confusion are concrete and derive directly from the AD wording:

1. Applicability exception based on MRB Task numbers: The AD excludes aircraft whose engine mount frames "have been inspected previously in accordance with the Fokker 50/60 MRB Document, Task Numbers 712000-00-09 and 712000-00-10." That creates a records issue: an operator claiming the exemption must be able to demonstrate that those specific MRB tasks were completed. The AD does not specify what documentary form is acceptable for that demonstration; therefore operators risk being treated as subject to the AD if their records are insufficiently specific, even if the physical inspection was done. The requirement to match the exact MRB task numbers is a narrow criterion.

2. Reliance on particular service bulletin sections and EASA approval: The inspection and spare‑part inspection duties are mandatory "in accordance with Section 3. Accomplishment Instructions" of specific Fokker service bulletins. The AD allows use of later revisions only if those revisions are "EASA approved." Two practical risks arise: (a) maintainers must ensure they are using the precise section of the correct service bulletin and correct revision; (b) if a later revision exists but has not yet been EASA‑approved, using that revision would not satisfy the AD. The AD does not provide guidance on acceptable deviations or who can confirm whether a revision is EASA‑approved.

3. Different compliance timing for spares and airframes: The AD sets different effective dates: the AD "becomes effective on 8 June 2006," the main inspection must be done "within 2 years after 8 June 2006," reporting must occur within seven days after inspection, but the spare‑mount prohibition states "After 15 June 2006" no uninspected spare may be installed. Operators must ensure they do not mix up these dates; installing a spare engine mount between 8 June and 15 June 2006 might create confusion. The AD provides no transitional guidance.

4. Reporting to Fokker Services within seven days: The AD requires all inspection results to be reported to Fokker Services "in accordance with the procedure described in SBF50-71-047." The AD does not reproduce the reporting procedure or provide an alternative. If an operator completes the inspection but cannot comply with the bulletin’s reporting procedure (for example if contact details have changed), the AD contains no remedy; failure to report within seven days risks technical non‑compliance. The AD creates a tight reporting window relative to the inspection completion.

5. Spare inventory control: The prohibition on installing spare engine mounts that have not been X‑rayed imposes a duty on parts controllers and maintenance planners to verify inspection status before fitment. That creates potential operational impacts if uninspected spares are in caches or stockpiles; operators must inspect spares or risk non‑compliance. The AD does not discuss the process for handling uninspected spares (for example, mandatory marking, quarantine, or traceability requirements).

6. Narrow technical cause and inspection scope: The AD bases its action on findings from MRB mid‑life X‑ray inspections that found severe internal corrosion in certain tubes. The AD mandates X‑ray in accordance with the specified service bulletin Section 3. If an operator elects a different non‑destructive technique (for example ultrasonic) the AD does not provide for that alternative in its text. Therefore, an operator that wishes to pursue alternative but technically equivalent inspections must resolve that outside the AD text.

7. Absence of enforcement detail in AD text: The AD contains no penalties or enforcement guidance. That lack of explicit enforcement language does not mean enforcement will not occur, but it means that the AD itself provides no procedural steps to follow if a party needs to seek relief, an extension, or to establish an alternative means of compliance. Operators must therefore engage with the regulator or manufacturer if questions arise.

8. Data flow confidentiality and use: The AD requires reporting to Fokker Services, but the AD gives no guidance on how Fokker will use or store the reported inspection data. Operators sensitive about the handling of inspection data (for example commercial or confidentiality concerns) will not find guidance in the AD text.

9. Geographic and regulatory linkage: The AD references EASA approvals and a Netherlands AD. Operators operating in multiple jurisdictions should note that the AD ties acceptable methods to EASA approvals; the AD does not set out domestic alternatives, and it does not specify whether actions already taken to comply with the CAA‑NL AD or EASA directives satisfy the AD unless the MRB Task numbers or EASA‑approved bulletins explicitly match.

10. Record sufficiency for spare‑part inspection: The AD requires a spare engine mount to have been X‑ray inspected "in accordance with" the referenced component service bulletin. The AD does not explain whether proof of inspection by a third party or a previous owner will suffice. Custodians of spares should maintain explicit inspection certificates linking the spare to the component service bulletin Section 3 to avoid ambiguity at fitment.

These items are the concrete operational uncertainties and administrative traps that appear inside the AD’s text. They are not speculative; they follow from the AD’s narrow reliance on exact MRB task numbers, precise service bulletin sections, specific dated bulletins (or EASA‑approved later revisions), strict short reporting windows, and the spare‑fitment prohibition without transition rules.

The AD prescribes a clear procedural route to compliance; below are practical, document‑grounded steps derived from the AD text. Each step cites the relevant requirement or provision of the AD.

1. Confirm applicability for each aircraft in the fleet:

   • Check the aircraft model and serial number against the AD’s applicability: Model F27 Mk 050, Mk 0502, and Mk 0604 aircraft, all serial numbers. (Applicability table.)
   • Determine whether the engine mount frames on the aircraft have been inspected previously "in accordance with the Fokker 50/60 MRB Document, Task Numbers 712000-00-09 and 712000-00-10." If such prior inspections were completed and can be documented, those aircraft are exempt from the AD’s inspection requirement. Make sure the documentary evidence explicitly references those MRB task numbers, because the exemption is expressed in those exact terms.

2. Obtain the mandatory technical documents and check approval status:

   • Acquire Fokker Service Bulletin SBF50-71-047, dated 15 February 2006, and Fokker Component Service Bulletin F8200-035-71-12, dated 15 February 2006. The AD requires compliance "in accordance with Section 3. Accomplishment Instructions" of those bulletins.
   • If you plan to use a later revision of either service bulletin, confirm that the later revision is EASA approved. The AD allows later revisions only if they are "EASA approved revision(s)." Do not use an unapproved later revision.

3. Schedule and perform the X‑ray inspection:

   • The inspection mandated by Requirement 1 must be completed "within 2 years after 8 June 2006." Schedule the X‑ray inspection so it is finished within that two‑year window.
   • Ensure the inspection is carried out in accordance with Section 3 of SBF50‑71‑047. Use qualified maintenance personnel and appropriate non‑destructive testing facilities for X‑ray inspection of engine mount tubing and end fittings.
   • If the aircraft has multiple engine mount frames, ensure each relevant tube and end fitting identified by Section 3 is inspected.

4. Record and report inspection results:

   • Requirement 2 mandates reporting "all inspection results to Fokker Services in accordance with the procedure described in SBF50-71-047." Follow the bulletin’s reporting procedure exactly.
   • The AD requires reporting "within 7 days of accomplishment of Requirement 1 inspection." Prepare the required documentation and submit to Fokker Services within that seven‑day period.
   • Keep a local copy of the inspection records and the proof of transmission to Fokker Services to demonstrate compliance and to support auditability.

5. Manage spare engine mounts:

   • From "after 15 June 2006" no spare engine mount may be installed unless it has been X‑ray inspected in accordance with Section 3 of Fokker Component Service Bulletin F8200‑035‑71‑12 (or later EASA‑approved revision). Before any installation of a spare, verify that the spare has been X‑rayed according to that bulletin.
   • If spares in inventory are not documented as having been X‑rayed per the bulletin, either arrange for the required X‑ray inspection of the spare or mark/quarantine the part to prevent inadvertent installation.
   • Maintain contemporaneous documentation for each spare (inspection certificate referencing the component service bulletin and Section 3) so that installation teams can verify compliance quickly.

6. Maintain documentary proof of compliance for audits:

   • Keep records that show the inspection was performed in accordance with the referenced service bulletin Section 3, the date of inspection, the inspection findings, and the date and method of submission to Fokker Services (to satisfy the seven‑day reporting duty).
   • For aircraft relying on the MRB exemption, retain the MRB task documentation that clearly references Task Numbers 712000‑00‑09 and 712000‑00‑10.

7. Coordinate scheduling to minimise operational impact:

   • The AD’s inspection may require downtime for the aircraft and access to X‑ray inspection facilities. Coordinate inspection scheduling with planned maintenance windows to mitigate aircraft availability impacts.
   • Ensure maintenance control, inventory managers and operations planners are aware of the spare‑part inspection requirement to avoid last‑minute inability to replace an engine mount with an uninspected spare.

8. Confirm who will perform and approve the inspection:

   • Use appropriately authorised maintenance organisations and personnel competent in X‑ray NDT for the engine mount components. The AD mandates the method but relies on the service bulletin for the technical detail; ensure the performing organisation follows Section 3 precisely.

9. Ensure that reporting procedures are current:

   • Follow the reporting procedure in SBF50‑71‑047. Confirm Fokker Services’ contact details and reporting channels (as specified in the bulletin) are current before inspection to avoid missed seven‑day reporting windows.

10. Seek clarification where the AD is silent:

    • The AD does not describe enforcement processes, alternative means of compliance, or how to treat ambiguous prior inspections. If there is uncertainty about whether a particular prior MRB inspection qualifies for the exemption, whether a later revision of a bulletin is EASA approved, or how to handle an unexpected finding in the inspection (for example extensive corrosion requiring repair or part replacement), engage with Fokker Services and the Civil Aviation Safety Authority to obtain formal clarification. The AD itself does not provide an alternative means of compliance within its text.

These steps are derived entirely from the AD’s requirements, references and compliance deadlines. The AD imposes the substantive technical duties by reference to the manufacturer’s bulletins and sets short reporting deadlines; operators should therefore prioritise obtaining the specified bulletins, validating EASA approval status of any later revisions and ensuring reporting channels to Fokker are functional prior to inspection.