AD/F100/66 - Wing Rear Spar Lower Girder

The directive is built on a small number of concrete regulatory concepts and textual hooks. These are the concepts an operator or maintainer must translate into action.

• Applicability. The AD explicitly limits its scope to "All Model F28 Mk 0070 and F28 Mk 0100 aircraft" (Applicability). The precise model identifiers are the controlling threshold for whether the directive applies to a particular airframe.

• Mandated technical method by reference. The AD does not set technical inspection detail in the body of the directive. Instead, it mandates compliance with Parts 1 and 2 of Section 3 of Fokker Services Service Bulletin F100-57-038 dated 15 April 2005, or a later CAA-NL approved revision (Requirement 1 and 2). The directive thereby incorporates the SB by reference as the required procedural standard for inspection and corrosion removal.

• Threshold-based outcomes. The directive contains a decision tree governed by measured "damage limits". If corrosion is found, the operator must remove corrosion, measure the resulting damage, and compare that measurement to defined limits in the referenced SB. If the damage is within those limits, the aircraft may return to service after restoration of surface protection (Requirement 2). If the limits are exceeded, the operator must contact Fokker Services and follow repair advice (Requirement 3). The directive therefore delegates substantive repair criteria to the SB and to Fokker Services' repair advice.

• Reporting obligation. Irrespective of whether corrosion is found or whether repairs are necessary, the AD requires that "report all findings to Fokker Services" (Requirement 4), and sets a seven-day window for that report (Compliance 4). The report obligation creates a data flow from operators to the manufacturer.

• Timing constraints. The AD sets both a mileage/usage window and calendar bounds: inspect at next scheduled or unscheduled maintenance within 4,000 flight hours after 7 July 2005, but not later than 15 April 2007 (Compliance 1). Corrective actions where required must be completed "before further flight" (Compliance 2 and 3). These timing rules impose both a maximum delay and a strict grounding requirement where damage limits are exceeded.

• Cross-reference to another regulator. The AD explicitly notes that "Netherlands CAA AD NL-2005-006 refers" (Requirement Note). The SB revision acceptance is conditioned on CAA-NL approval, and the AD refers to an AD issued by the Netherlands CAA, which is relevant to traceability and possible parallel directives.

These concepts define the operational steps and the delegated decision points: the SB and Fokker Services determine inspection detail, corrosion removal procedure, damage limits, and repair advice; the directive imposes timelines, reporting, and the obligation to follow the SB or later CAA-NL approved revisions. The operator must therefore combine its maintenance scheduling, the SB procedures, and the reporting flow to meet the AD.

The directive names its affected fleet explicitly: "All Model F28 Mk 0070 and F28 Mk 0100 aircraft" (Applicability). That is the textual scope; any airframes of those models in an operator's fleet are captured. The AD also identifies several named institutional actors:

• Aircraft operators and maintainers responsible for inspection and repair. The AD requires inspection, corrosion removal, measurement, repair where damage limits are exceeded, and reporting; those tasks are operational responsibilities that fall to the operator or its contracted maintenance organisation. The actions specified are standard maintenance and repair activities as defined in the SB reference; the AD imposes them as mandatory duties.

• Fokker Services. The SB referenced is a Fokker Services Service Bulletin (SB F100-57-038, dated 15 April 2005). The AD requires operators to follow the SB instructions and, where damage limits are exceeded, to "contact Fokker Services and repair in accordance with the repair advice as provided by Fokker Services" (Requirement 3). The AD therefore makes Fokker Services the recipient of reports and the primary technical adviser for repairs beyond the SB's damage limits.

• Civil Aviation Safety Authority (CASA) through its delegate. The document is signed by David Villiers, Delegate of the Civil Aviation Safety Authority (signature block and date 19 May 2005). The AD is an instrument issued under CASA authority, so regulatory compliance and recordkeeping will be monitored under CASA's oversight framework.

• Netherlands CAA. The AD explicitly refers to "Netherlands CAA AD NL-2005-006" (Requirement note) and conditions revision acceptance to "later CAA-NL approved revision", linking the technical standard and revision control to the Netherlands CAA process.

Who pays: the directive text does not explicitly allocate costs, but it places operational duties (inspection, corrosion removal, measurement, repairs, reporting) on operators and maintainers. Consequently, the financial outlays for inspections, materials, labour, potential repairs, and reporting are obligations that operators and their maintenance providers will incur if the AD applies to their aircraft. The AD itself does not offer financial assistance or exemptions.

Who decides: technical decisions are split. The SB sets inspection and removal procedures and damage limits for return-to-service, while Fokker Services is the contact point for repair advice if limits are exceeded. The regulatory decision to require these steps, to set timelines and to require reporting, is exercised by CASA (the signing delegate). The directive therefore creates a hybrid decision architecture where field-level technical judgments reference the SB and Fokker Services, and regulatory enforcement rests with CASA delegation.

The AD sets out a concise set of duties for operators and maintainers, and a limited set of implied rights.

Primary duties (as written in the AD)

• Inspect the structure. Requirement 1 mandates inspection "between STA 8700 and STA 9200" of the wing rear spar lower girder, following Part 1 of Section 3 of SB F100-57-038, dated 15 April 2005, or a later CAA-NL approved revision. This is a prescriptive duty to use the SB methodology.

• Corrosion removal and measurement. Requirement 2 requires that, if corrosion is found, it be removed in accordance with Part 2 of Section 3 of the SB, and that the damage be measured. Operators must determine whether the measured damage exceeds the SB's damage limits and either return the aircraft to service (if limits are not exceeded) after restoring surface protection, or proceed to further steps.

• Repair where limits exceeded. Requirement 3 requires contact with Fokker Services and repair in accordance with Fokker Services' repair advice where damage limits are exceeded. The AD thereby delegates repair design and approval to the manufacturer.

• Reporting. Requirement 4 mandates that "irrespective of the results, report all findings to Fokker Services." Compliance requires submission within seven days of inspection (Compliance 4).

Timing duties

• Inspection window. Compliance 1 imposes a timing duty to inspect "at the next scheduled or unscheduled maintenance check within 4,000 flight hours after 7 July 2005, but not later than 15 April 2007." Operators must schedule or expedite inspections accordingly.

• Immediate action before further flight. Compliance 2 and 3 require that corrective actions (removal and repair where applicable) be completed "before further flight." Where damage limits are exceeded this creates an immediate grounding requirement until repair actions per Fokker Services are completed.

Rights and mechanics implied by the AD

• Right to use later approved revisions. The AD permits the use of "later CAA-NL approved revision" of the SB as the accepted method. This grants operators the right to rely on updated SB instructions provided those revisions have CAA-NL approval.

• Procedural reliance on the SB and Fokker Services. The AD delegates technical content to the SB and to repair advice from Fokker Services; operators have the right to rely on those documents and the manufacturer’s repair instructions as the accepted compliance path.

• Reporting channel. Operators must report to Fokker Services; the AD creates a direct communication channel that operators will use to discharge the reporting duty.

Duties not specified

• The AD does not specify record retention durations, sanctions, or the administrative process for CASA oversight in this text. It also does not specify a particular form or content for the report to Fokker Services. Those procedural details are not in the AD's text and therefore must be followed as required by the SB, by Fokker Services' instructions, or by CASA guidance where applicable.

In short, the AD imposes mandatory inspection, corrective and reporting duties, gives operators the procedural option to use later CAA-NL approved SB revisions, and places the manufacturer as the technical adviser for repairs where damage limits are exceeded.

The AD text itself does not set out penalties, fines, or explicit enforcement processes. The document sets mandatory actions and timelines (inspect within the specified flight hours or by calendar date; correct defects before further flight; report within seven days), but it contains no section describing penalties for non-compliance, administrative sanctions, or criminal liability. The AD was executed by a CASA delegate (signature block: David Villiers, 19 May 2005) and therefore operates as a regulatory instrument; the text prescribes duties but is silent on enforcement mechanisms in the document.

Because the AD requires specific maintenance actions and sets "before further flight" constraints where damage limits are exceeded, the practical enforcement mechanism is operational: non-compliant aircraft would not meet the AD's return-to-service conditions. The AD leaves technical thresholds (damage limits) and repair methods to the referenced SB and to Fokker Services' repair advice. Compliance assessment will therefore depend on whether the operator followed the SB and contacted Fokker Services where the SB's limits were exceeded.

Reporting obligations are explicit: operators must "report all findings to Fokker Services" within seven days. Failure to report is a breach of the AD's requirements as written, but the AD does not spell out the administrative or statutory consequences of such a breach within this text.

The document's note that "Netherlands CAA AD NL-2005-006 refers" suggests coordination with an AD issued by another jurisdiction, but the AD does not set out mechanisms for cross-jurisdictional enforcement. There is no mention of inspector powers, audits, or penalty schedules within the AD text.

Practically, enforcement and penalties would be expected to be administered through CASA's regulatory framework, not through this AD's text; however, the AD does not itself specify that framework or identify the specific enforcement steps. The reader must therefore look beyond the AD text, to CASA's general enforcement procedures and to organisations' obligations under applicable aviation safety legislation, for the concrete enforcement instruments and penalty regimes.

The AD references and therefore interacts with at least one foreign regulator's directive and embeds reliance on a manufacturer service bulletin. Interactions expressly present in the text are limited to these cross-references:

• Netherlands CAA. The AD explicitly notes that "Netherlands CAA AD NL-2005-006 refers" (Requirement note). The reference creates a linkage to that other regulator's finding or instruction. The SB acceptance mechanism is also conditioned on "later CAA-NL approved revision", which makes the Netherlands CAA the approving authority for any later revisions of the referenced SB that will be treated as compliant under this AD.

• Manufacturer service bulletin. The AD requires execution "in accordance with Part 1 of Section 3 Accomplishment Instructions of Fokker Services Service Bulletin (SB) F100-57-038, dated 15 April 2005, or later CAA-NL approved revision" (Requirement 1), and references Part 2 for corrosion removal. By mandating the SB, the AD effectively incorporates its technical content into the regulatory requirement. This produces an interaction between regulatory law and industry technical standards: the SB is the technical method of compliance.

The text does not set out interactions with domestic statutes, administrative processes, or specific CASA enforcement instruments. The AD is signed by a CASA delegate (19 May 2005), which shows it is issued under CASA authority, but the AD does not recite the underlying enabling statute or administrative procedures in the text supplied. There is therefore an implicit interaction: the AD sits within CASA's broader regulatory authority and enforcement framework, but the AD itself does not spell out how it sits within that legislative architecture.

The AD also delegates some technical decision-making to Fokker Services (repairs where damage limits are exceeded, and receipt of reports). That connection creates a de facto regulatory-manufacturer interaction, where the manufacturer provides repair advice that operators must follow to meet the AD's requirements.

Absent from the AD text are references to record-keeping statutes, export/import rules, airworthiness certificate conditions, or commercial contract law. The directive does not mention how compliance affects continuing airworthiness certificates or whether compliance must be recorded in particular maintenance logs; these are not in the AD itself. Operators will therefore need to align the AD's duties with any broader legal requirements governing maintenance records, certificate endorsements, or national administrative procedures outside this text.

In short, the AD references and depends on a specific manufacturer SB and a Netherlands CAA AD, and it is issued by CASA. Other statutory interactions are not specified in the directive's text.

The AD text provides limited, specific information relevant to amendment and revision processes.

• Dates and effective date. The AD is labelled "AD/F100/66", with the date marker "7/2005" in the header. The face of the document records that the AD "becomes effective on 7 July 2005" (Compliance note) and bears the signatory block "David Villiers, Delegate of the Civil Aviation Safety Authority, 19 May 2005." These dates record issuance and the effective date.

• Incorporation of later revisions. The AD expressly permits operators to follow "Part 1 of Section 3 Accomplishment Instructions of Fokker Services Service Bulletin (SB) F100-57-038, dated 15 April 2005, or later CAA-NL approved revision" (Requirement 1) and similarly for Part 2 (Requirement 2). That phrasing is the operational mechanism by which later technical revisions to the SB, once approved by the Netherlands CAA (CAA-NL), become acceptable means of complying with the AD. This provides a channel for technical amendments without amending the AD text itself: the referenced SB can be updated, and, if that update is approved by CAA-NL, the newer SB revision is acceptable under the AD.

• Reference to Netherlands CAA AD. The AD notes "Netherlands CAA AD NL-2005-006 refers." That cross-reference suggests that the Netherlands CAA's AD content is part of the historical and potentially evolving regulatory context relevant to AD/F100/66. Any amendment or revocation of the Netherlands AD, or any changes to CAA-NL approval practice, could affect which SB revisions are accepted under the AD.

• No listed domestic amendments. The document as supplied does not list subsequent amendments, revocations, supersessions, or corrigenda within its text. There is no schedule of amendment history or version log in the instrument itself beyond the effective date and allowance for later CAA-NL approved SB revisions.

Mechanically, therefore, the AD allows amendment of the technical compliance route through updated SB revisions (subject to CAA-NL approval), but the AD's own text does not specify processes for formal amendment, extension, or revocation of the AD itself. The AD's effective date and issuance date are recorded, but no subsequent changes are recorded in the supplied text.

Operators and maintainers seeking to rely on later SB revisions must ensure that those revisions are "CAA-NL approved" as specified in the AD's text; approval by another authority is not identified in this AD as sufficient. Any revision history of the AD itself would need to be checked against CASA records outside the AD text supplied.

The supplied AD text contains no litigation history, judicial references, or mentions of legal challenges. There are no cited cases, appeals, or tribunals noted in the document. The AD refers to a Netherlands CAA AD NL-2005-006 and to Fokker Services SB F100-57-038, but it does not mention any disputes, enforcement actions, or court proceedings arising from its issuance.

Because the AD text does not document any legal proceedings, no litigation outcomes, case names, or appeals are available within this instrument. Any inquiry about litigation related to this AD or to the underlying safety issue would require consulting external legal databases, administrative records, or CASA case files; those sources are not part of the AD text provided.

Consequently, within the limits of the supplied text, there is no recorded litigation history and no judicial interpretation of the AD to summarise.

The AD's concise format leaves several practical pitfalls and attention points that operators and maintainers should note. These are drawn strictly from the text.

• Narrow applicability language. The AD applies to "All Model F28 Mk 0070 and F28 Mk 0100 aircraft" (Applicability). Small transcription differences in model identifiers could matter when matching records. Confirm the model designation used in the operator's maintenance and registration records exactly matches the phraseology in the AD.

• Inspection scope defined by station limits. The required inspection is confined to the wing rear spar lower girder "between STA 8700 and STA 9200" (Requirement 1). Maintenance planners must ensure inspection teams inspect the correct structural stations; misidentifying the station band could lead to incomplete compliance.

• Mandatory use of a specific SB version unless CAA-NL approves a later revision. The AD expressly ties compliance to SB F100-57-038 dated 15 April 2005, "or later CAA-NL approved revision" (Requirement 1). That means a later SB revision must be approved by the Netherlands CAA to be accepted under this AD. Using a later SB without that CAA-NL approval is not authorised by the AD as written.

• Timing pitfalls: two-step timing rule. Compliance 1 requires inspection "at the next scheduled or unscheduled maintenance check within 4,000 flight hours after 7 July 2005, but not later than 15 April 2007." Operators must ensure they do not mistakenly treat the 4,000 flight-hour window as the only constraint; the calendar cap (15 April 2007) is an absolute backstop. Planning must account for both hour-counts and calendar deadlines.

• "Before further flight" obligations. Compliance 2 and 3 mandate that removal of corrosion and repair where damage limits are exceeded must be completed "before further flight." In practice this means if corrosion removal reveals damage beyond specified limits, the aircraft cannot resume flight until repair advice from Fokker Services is followed and repairs completed. Operators should ensure they have processes to handle aircraft being grounded pending manufacturer repair advice.

• Damage limits located in SB. The AD requires measurement and comparison against damage limits, but those damage limits are not printed in the AD , they are in the SB. Failure to use the correct SB revision or to identify the correct damage limit table in the SB could cause incorrect return-to-service decisions.

• Reporting timing: seven days. The AD requires reporting "irrespective of the results" and sets a seven-day window for reporting findings to Fokker Services (Compliance 4). Operators must have reporting workflows that meet this timeframe. The AD does not prescribe the format or content of the report, creating potential ambiguity about what constitutes an acceptable report.

• Reliance on manufacturer for repair advice. Requirement 3 requires operators to "contact Fokker Services and repair in accordance with the repair advice as provided by Fokker Services" where damage limits are exceeded. Operators should be prepared for variability in turnaround time for manufacturer repair advice and for potential logistical constraints if repairs necessitate specialised parts or procedures.

• No enforcement details in the AD text. The AD does not list specific enforcement mechanisms or penalties for non-compliance. That absence does not mean non-compliance is without consequence; however, the AD text provides no administrative guidance on notices, audits, or penalties.

• Cross-jurisdictional approval requirement. The acceptability of later SB revisions depends on "CAA-NL approved revision" status. For operators in other jurisdictions, this means checking Netherlands CAA approval status rather than relying solely on local approval listings.

Operators should treat the AD as a compact, mandatory instruction set that references external technical documents and a foreign regulator's approval. Missing any of the external links (SB revision, CAA-NL approval, Fokker Services communications) would create compliance risk.

The AD sets a specific procedural sequence. The following is a step-by-step compliance checklist distilled from the AD text. Each step cites the AD's numbered requirements and compliance instructions.

1. Confirm applicability. Verify whether each airframe is a "Model F28 Mk 0070" or "F28 Mk 0100" as specified in the Applicability section. If an airframe matches those model identifiers, the AD applies.

2. Identify the inspection area. The affected structure is the wing rear spar lower girder "between STA 8700 and STA 9200" (Requirement 1). Ensure maintenance documentation and technicians use the correct station reference during inspection.

3. Obtain the correct SB revision. Acquire Fokker Services Service Bulletin F100-57-038 dated 15 April 2005. If there is a later SB revision, confirm whether it is "CAA-NL approved," because only approved later revisions are acceptable under the AD (Requirement 1).

4. Schedule the inspection within the AD timing. Arrange the inspection "at the next scheduled or unscheduled maintenance check within 4,000 flight hours after 7 July 2005, but not later than 15 April 2007" (Compliance 1). If an aircraft is within that flight-hour window or approaching the calendar cap, prioritise the inspection accordingly.

5. Perform the inspection per Part 1, Section 3 of the SB. Carry out the inspection procedures set out in Part 1 of Section 3 of the SB. Document findings; maintain records consistent with the SB and the operator's maintenance control procedures (Requirement 1).

6. If corrosion is found, execute corrosion removal per Part 2. Follow Part 2 of Section 3 of the SB for removal of corrosion and then measure the damage as required by the SB (Requirement 2). Do not perform ad hoc removal methods that depart from the SB unless authorised by CAA-NL or Fokker Services.

7. Compare measured damage to SB damage limits. Use the damage-limit criteria in the SB to determine whether the damage exceeds allowable limits. If damage limits are not exceeded, restore surface protection in accordance with the SB, and the aircraft "may be returned to service" after that restoration (Requirement 2).

8. If damage limits are exceeded, contact Fokker Services immediately. Requirement 3 mandates contacting Fokker Services and repairing "in accordance with the repair advice as provided by Fokker Services." Do not return the aircraft to service until repairs per the manufacturer's advice are completed (Compliance 3, which requires action "before further flight").

9. Grounding decisions. Where the measurement indicates limits are exceeded, do not allow further flight until repairs are carried out per Fokker Services' instructions. The AD specifies that remedial actions constrained by damage limits must be completed "before further flight" (Compliance 2 and 3).

10. Report all findings to Fokker Services within seven days. Irrespective of whether corrosion was found or repairs were necessary, submit a report to Fokker Services within seven days of inspection (Requirement 4; Compliance 4). Because the AD does not specify report content or form, align the report with any Fokker Services reporting templates or guidance, and keep copies in the maintenance file.

11. Record-keeping and traceability. Although the AD does not spell out specific record-retention requirements, maintain clear maintenance records showing the inspection date, SB revision used, findings, measurements, corrosion removal actions, repairs undertaken, and the report submitted to Fokker Services. These records will be relevant if CASA requests evidence of compliance.

12. Use approved SB revisions only. If relying on a later SB revision, confirm CAA-NL approval status before performing the work. Keep documentation of that approval alongside the maintenance workpack to show the AD-compliant technical method was used.

13. Liaise with maintenance control and regulatory affairs. Inform regulatory and technical management of any aircraft grounded pending Fokker Services repair advice, so that operational and regulatory reporting obligations are coordinated.

14. Monitor for follow-up directives. The AD references Netherlands CAA AD NL-2005-006. Operators should monitor communications from Fokker Services and CASA for any follow-up airworthiness directives or updated instructions that might change the inspection method, damage limits, compliance windows, or reporting procedures.

Who bears cost and responsibility. The AD places operational duties on the operator/maintainer and requires contact with Fokker Services for repair advice. As such, the operator is responsible for scheduling and paying for the inspection, corrosion removal, measurement, any required repairs, and for preparing and sending the report to Fokker Services.

Practical tips. Ensure the inspection team has access to the correct SB and understands how to measure damage against the SB's limits. Establish an escalated communication path to Fokker Services to reduce turnaround time if the damage exceeds limits. Finally, maintain clear documentation of the inspection and any repairs, and preserve evidence of the SB revision used and the seven-day report submission to Fokker Services.