AD/F50/79 Amdt 4 - Control Surfaces Leading Edge Attachment

The AD organises airworthiness corrective action around two central concepts: recurring inspections with corrective action, and a one‑time terminating modification.

1. Recurring inspection and corrective action. Requirements 1-3 direct maintenance personnel to check the torque value of the leading edge attachment screws for the elevator, rudder and aileron respectively, and to take corrective action if necessary. Each check is to be performed "in accordance with the Accomplishment Instructions" of the specified Fokker SBs (F50‑55‑007 Rev 2; F50‑55‑009 Rev 2; F50‑57‑020 Rev 2, all dated 17 June 2002). The AD sets initial deadlines and maximum recurring intervals for these checks, and explicitly conditions their continuance "until compliance with Requirement 4." The structure makes the inspections a temporary recurring burden pending the terminating modification.

2. Terminating modification. Requirement 4 prescribes installation of "additional locking devices" on the flight control leading edge attachments, with separate service bulletin instructions for rudder, ailerons and elevators (F50‑55‑010 Rev 2; F50‑57‑021 Rev 2; F50‑55‑008 Rev 3). Note 1 defines the legal effect: completing Requirement 4 terminates the ongoing repetitive check requirements. Thus the AD creates a trade: perform periodic checks indefinitely (within prescribed intervals) until undertaking a one‑off modification that removes the recurring obligation.

3. Source documents as normative instructions. The AD does not set out method details itself; instead, it mandates compliance "in accordance with the Accomplishment Instructions" of the listed Fokker SBs and cites specific revision numbers and dates. Those manufacturer documents are therefore incorporated by reference into the AD’s required method and technical content.

4. Phased tightening of intervals. The Background and Amendment 4 state that the AD is a product of successive amendments that expanded scope and adjusted intervals. Amendment 4 specifically "reduces the intervals for inspection and re‑tightening of the flight control surfaces leading edge attachment screws" and introduces a hard time‑since‑new limit for completing the modification. The AD therefore both tightens interim surveillance and sets a definitive deadline for terminating action.

5. Authority and notification. The AD is issued by a CASA delegate under subregulation 39.1(1) of CAR 1998 and was notified in the Commonwealth of Australia Gazette. It also references a related Netherlands CAA AD (2000‑131/2), signalling an interaction with foreign regulatory action.

These elements create a prescriptive compliance regime that assigns technical method to manufacturer SBs, sets time windows and intervals for inspection and corrective work, and specifies a single modification that, once accomplished, removes the repetitive inspection obligation.

The AD nominally affects the owners and operators of Model F27 Mk 050, Mk 0502 and Mk 0604 aircraft, across all serial numbers, because those aircraft are included in the Applicability paragraph. The text makes several practical allocations of responsibility and decision rights.

• Operators/owners. The AD obliges action "in relation to the aircraft" and sets deadlines and intervals for inspections and modifications. That places operational responsibility (scheduling, funding, arranging work) with the aircraft owner/operator who must ensure the aircraft are maintained in compliance with the AD. The AD’s compliance windows reference both calendar time and flight hours for Requirement 2, making operator flight activity relevant to scheduling.

• Maintenance organisations and authorised maintenance personnel. The AD requires that torque checks and corrective action be performed "in accordance with the Accomplishment Instructions of Fokker Service Bulletin..." The entity capable of performing those instructions in a compliant manner will typically be the aircraft operator’s maintenance organisation or an appropriately authorised third‑party maintenance provider. The AD does not itself authorise who may carry out the work; it prescribes the SB methodology that maintenance personnel must follow.

• The Civil Aviation Safety Authority and its delegate. The AD is issued by a CASA delegate under CAR 1998 subregulation 39.1(1). The delegate’s signature appears on the document and the AD revokes the previous Amendment 3. That indicates the CASA delegate and CASA as regulator decide the legal requirement, the applicability and the compliance timetable.

• International regulator interaction. The AD references Netherlands CAA AD 2000‑131/2 (Note 2) and states Amendment 4 was issued in response to a new issue of that related CAA‑NL AD. This implies that regulators and potentially operators subject to both jurisdictions may coordinate, and that SBs and the AD’s technical content respond to findings from another state of design or certification authority.

• Maintenance programmes and record-keepers. Because Requirement 4 is terminating, the operator who completes the modification must update the aircraft maintenance records and maintenance programme to remove the recurring inspection requirements. The AD does not give a form for record updates, but the legal requirement to have the inspections cease after modification means maintenance records must reflect the modification work in order to demonstrate compliance.

• Aircraft with different ages and utilisation profiles. The AD sets differing compliance triggers that depend on calendar age ("15 years time‑since‑new" in Compliance 4) and usage (4,000 flight hours or 24 calendar months in Compliance 2). Thus older airframes and higher‑utilisation aircraft are affected differently for scheduling and prioritisation.

The AD does not list exemptions, alternative methods of compliance, or appeals in its text. The document does not set out who pays for parts, labour or downtime; however, because it places the obligation on aircraft to be inspected and modified "in relation to the aircraft", the practical burden of cost and scheduling falls on the aircraft owner/operator and their maintenance providers.

Key duties

• To inspect and correct torque values. Requirements 1-3 impose mandatory duties to "check the torque value" of the leading edge attachment screws for elevator (Req 1), rudder (Req 2) and aileron (Req 3), and to "take corrective action, as necessary" per the Accomplishment Instructions of the specified Fokker Service Bulletins (each cited by number, revision and date). The Accomplishment Instructions are incorporated into the AD as the required method.

• To carry out the terminating modification. Requirement 4 requires modification "by installing additional locking devices" on the leading edge section attachments for rudder, ailerons and elevators, again in accordance with the specific Fokker SBs cited with revision numbers and dates.

• To meet specified compliance times and recurring intervals. The AD sets concrete timing obligations:

  • Requirements 1 and 3: initial compliance within six months after 31 October 2002 or at expiry of the previous 12‑month interval required by the prior issue of the Directive, whichever occurs first; thereafter at intervals not to exceed six calendar months; until Requirement 4 is complied with.
  • Requirement 2: initial compliance within 12 months after 31 October 2002 or at expiry of the previous 4,000 flight hours or 24‑month interval required by the prior issue, whichever occurs first; thereafter at intervals not to exceed 12 calendar months; until Requirement 4 is complied with.
  • Requirement 4: within 24 calendar months after 31 October 2002 or by 15 years time‑since‑new of the aircraft, whichever occurs first.

• To follow the exact SB Accomplishment Instructions. The AD specifies the SBs by number, revision and date; maintenance must follow those instructions to meet the AD.

• To treat Requirement 4 as terminating action. Note 1 makes it a duty to recognise that once Requirement 4 is completed, the recurring checks required by Requirements 1-3 are no longer required.

Key rights and legal features

• The AD is issued under statutory authority. The opening paragraph states it is issued by the CASA delegate "under subregulation 39.1(1) of CAR 1998." That provides the legal basis for the directive and indicates the delegate’s decision‑making power to revoke the prior amendment and impose new requirements.

• Termination right of modification. Operators have a concrete legal right, created by the AD, to eliminate the recurring inspection duty by complying with Requirement 4; Note 1 makes this explicit.

• Reference to foreign regulator. Note 2 refers to Netherlands CAA AD 2000‑131/2. While the AD does not confer rights under that foreign AD, the reference signals that the AD’s content is related to obligations or findings adopted elsewhere; operators may have corresponding duties under other jurisdictions if they operate internationally.

Matters not specified in the AD

• The AD does not set out exemptions, alternative methods of compliance (AMOCs) or administrative appeal rights within its text. It also does not specify penalties, nor does it set out in‑house approval requirements for maintenance organisations. Those matters, if available, will be found in the statutory scheme (CAR 1998) and CASA administrative practice rather than inside this AD document.

• The AD does not provide explicit instructions for recordkeeping, although standard airworthiness practice requires maintenance records to show compliance. The AD does state when actions must occur, implying that demonstrable records will be necessary to evidence compliance.

The AD itself does not list specific penalties or enforcement mechanisms. It states that it is issued under the authority of the CASA delegate pursuant to subregulation 39.1(1) of CAR 1998 and that the AD requires the listed action be taken "in relation to the aircraft ... in accordance with the instructions ... at the time mentioned in the compliance section." The document was notified in the Commonwealth of Australia Gazette and became effective on 31 October 2002.

What is in the instrument

• Legal authority. The AD explicitly declares its statutory foundation in CAR 1998 subreg 39.1(1). That identifies the legal power used to require the inspections and modification.

• Notification and effectivity. It states the effective date (31 October 2002) and that it was notified in the Commonwealth Gazette on 9 October 2002. Publication in the Gazette is the administrative step used to notify regulated parties.

What the AD does not state

• No penalties detailed. The AD does not specify fines, licence sanctions, or criminal penalties for non‑compliance. It likewise does not describe CASA enforcement processes or consequences for operating an Aeroplane that has not complied with the AD.

• Enforcement is left to the regulatory framework. Because the AD derives from CAR 1998, enforcement and penalties would arise from the wider regulatory framework (for example, provisions in CAR 1998 governing contravention of airworthiness directives or operation of non‑airworthy aircraft). Those provisions are not reproduced in or summarised by the AD, and therefore this AD does not itself define specific sanctions.

Practical enforcement implications that follow from the AD text

• The AD creates an obligatory technical standard. Operators must perform the checks and modifications according to the specified SBs and within the set time windows. Compliance will be demonstrable by maintenance records showing torque checks, corrective actions, and the installation of the locking devices. The AD’s requirement that actions be taken "in accordance with" the SBs makes the SB instructions the relevant compliance standard.

• CASA delegate authority. The signature of the CASA delegate signals administrative enforceability; the AD revokes the prior amendment and restates required action under the delegate’s authority. Enforcement in practice will follow CASA’s enforcement regime under the CAR 1998 framework, even though specific penalties are not stated in this AD.

Because the AD does not list penalties, practitioners should consult CAR 1998 and CASA enforcement policy and guidance to understand the concrete legal consequences of non‑compliance and the processes for any administrative or legal action.

The AD cites and uses regulatory and international reference points that create interactions with other legal instruments.

Statutory foundation

• CAR 1998. The AD is issued under subregulation 39.1(1) of CAR 1998. That establishes a direct interaction between this AD and the Civil Aviation Regulations framework. The AD therefore functions as an enforceable direction within the CAR 1998 scheme, and any broader legal consequences (for example, penalties for contravention) will be governed by CAR 1998 and related regulatory instruments. The AD itself does not reproduce the substance of those other provisions.

Interaction with prior ADs and amendments

• Revocation and continuity. The AD expressly revokes AD/F50/79 Amdt 3 and replaces it with Amendment 4. The compliance paragraphs make repeated references to "the previous issue of this Directive" for the purpose of calculating the "expiry" of intervals. That means operators must cross‑reference the prior AD texts to determine exact prior intervals and expiry points. The AD therefore interacts operationally with the prior Directive by tying some initial compliance triggers to the schedule in the prior issue.

Interaction with manufacturer service bulletins

• Service Bulletins as incorporated method. The AD requires actions "in accordance with the Accomplishment Instructions" of specific Fokker SBs cited by revision and date. These SBs are de facto incorporated by reference into the AD as the normative technical instructions for compliance. The AD creates an obligation to follow manufacturer SB methods; thus, it interacts with the legal status of SBs: although SBs are typically non‑mandatory manufacturer guidance, incorporation in an AD makes the SB instructions mandatory for compliance with the AD.

International regulatory interaction

• Netherlands CAA AD 2000‑131/2. Note 2 references this CAA‑NL AD and the Background states Amendment 4 was issued in response to a new issue of that related CAA‑NL AD. That reference indicates cross‑jurisdictional regulatory influence: findings and requirements from the Netherlands CAA informed CASA’s decision to change intervals and introduce a limit for modification compliance. For operators that also operate internationally, there may be parallel obligations under the Netherlands CAA AD or other foreign directives; the AD does not displace those obligations but signals consistency with actions taken by the state of design or certification authority.

Administrative publication requirements

• Gazette notification. The AD was notified in the Commonwealth of Australia Gazette on 9 October 2002 and became effective on 31 October 2002. Gazette publication interacts with administrative law and public notice requirements: it serves as the formal notification mechanism in Australian administrative practice for the imposition of airworthiness directives.

Gaps and implied interactions

• Penalties and enforcement. The AD does not specify penalties; enforcement therefore defaults to the wider CAR 1998 enforcement provisions and CASA policy. Any procedural rights (such as review or appeal of CASA decisions) will also arise under the general administrative law and CAR 1998 framework, not the AD itself.

• Maintenance approvals and recordkeeping. The AD requires actions in accordance with SBs but does not specify who may perform them. Interaction with CAR 1998 maintenance authorisation provisions, maintenance organisation approvals and licence rules is implied: compliance must be demonstrably performed by appropriately authorised personnel and recorded in maintenance logs, as required under the broader regulatory framework.

In summary, the AD sits within the CAR 1998 regime, incorporates manufacturer service bulletins as mandatory instructions, cross‑references an overseas CAA AD, revokes the prior amendment and relies on Gazette publication for formal notification. Legal consequences and procedural rights beyond the technical requirements will be determined by CAR 1998 and CASA practice rather than by the AD text itself.

The AD text explicitly records the lineage of the directive and the changes made at each stage. Below are the amendments and the specific changes stated in the document.

• Original issue (effective 10 September 1999). The AD’s original issue became effective on 10 September 1999. The document does not reproduce the full original text here, but records that date as the initial effective date.

• Amendment 1 (effective 12 August 1999). The AD states "Amendment 1 expanded the AD inspection to include attachment screws of the rudder and aileron leading edges." The effective date is recorded as 12 August 1999. The AD text shows that Amendment 1 broadened the scope of the inspection requirements to include control surfaces beyond the elevator.

• Amendment 2 (effective 30 December 1999). The AD states "Amendment 2 expanded the compliance requirements for the rudder leading edge attachment screws; as a result of a recent evaluation which concluded that the rudder is of less airworthiness concern than originally envisaged, and the requirement for rudder removal to accomplish the task." In other words, Amendment 2 modified the compliance approach for the rudder: changing the scope/timing and removing the prior requirement to remove the rudder to accomplish the task. The effective date is recorded as 30 December 1999.

• Amendment 3 (effective 22 March 2001). The AD states "Amendment 3 required modification action by installing additional locking devices; which terminates the on‑going repetitive check requirements." Thus Amendment 3 introduced the terminating modification (additional locking devices) as a formal requirement, with the stated legal effect of ending the need for repeated inspections after modification. Amendment 3 became effective on 22 March 2001.

• Amendment 4 (issued 19 September 2002; effective 31 October 2002). This document is Amendment 4. The Background sets out the reasons for Amendment 4: it was issued in response to a new CAA‑NL AD which reduced inspection intervals and introduced a new limit for compliance with the required modification. It was prompted by operator reports, including an in‑flight vibration and the subsequent discovery of a loose elevator leading edge that had been inspected seven months prior. The AD text states Amendment 4 reduces the intervals for inspection and re‑tightening and introduces a hard limit for when the terminating modification must be accomplished (Compliance 4: within 24 calendar months after 31 October 2002 or 15 years time‑since‑new, whichever occurs first). The AD revokes the previous AD/F50/79 Amdt 3 and issues this Amendment 4 under the CASA delegate’s authority. The document was signed by the CASA delegate, David Charles Punshon, on 19 September 2002 and the AD became effective on 31 October 2002, having been notified in the Commonwealth Gazette on 9 October 2002.

The amendment history as recorded in the AD shows an iterative regulatory process driven by operator reports and by parallel action from the Netherlands CAA. Each amendment either expanded scope (Amendment 1), adjusted compliance technique and requirements (Amendment 2), added a terminating modification (Amendment 3), or tightened inspection intervals and introduced a firm deadline for the terminating modification (Amendment 4).

Practically, the AD requires operators and maintainers to read both the current Amendment 4 text and to cross‑reference prior issues where Compliance paragraphs tie initial actions to "the expiry of the ... interval as required by the previous issue of this Directive." That creates an operational dependency on the prior amendment texts for precise calculation of deadlines for initial repetitive inspections.

The AD document contains no litigation history or references to judicial decisions. It records operator incident reports and administrative amendments but does not cite any court proceedings, appeals or enforcement actions arising from the AD.

What the AD records

• Incident reports that prompted regulatory action. The Background section sets out factual incidents: an after‑landing incident in which elevator control was found binding and a later operator report of in‑flight vibration with discovery of a loose elevator leading edge section. Those operational incidents provided the factual basis for the AD’s issuance and amendment history, but they are not legal cases.

• International regulatory cross‑reference. The AD references Netherlands CAA AD 2000‑131/2, and states Amendment 4 was issued in response to a new issue of that CAA‑NL AD. The AD does not record any legal proceedings arising from the Netherlands AD either.

Absence of litigation references

• No cases named. The document names no cases, no enforcement proceedings, and no appeals. It therefore supplies no primary material on litigation generated by compliance or non‑compliance with the AD.

Implications for legal research

• To identify any litigation that may have arisen from the events or from application of this AD, interested parties will need to search external legal databases, tribunal records or CASA enforcement records. Those searches are outside the four corners of this AD text because the AD itself contains no litigation history.

• The AD’s lack of litigation references does not preclude subsequent enforcement or litigation under CAR 1998; it simply means none are recorded in this instrument.

For present purposes, practitioners should treat the AD as an administrative instrument setting technical obligations and rely on separate legal research to ascertain whether any enforcement notices, prosecutions, civil litigation, or tribunal appeals related to this AD occurred after its issuance.

The AD contains several technical and procedural features that can cause compliance missteps if they are not read carefully. These are specific, source‑grounded practical pitfalls to watch for.

1. Multiple differing compliance triggers and intervals. The AD sets different initial compliance triggers and recurring intervals for Requirements 1, 2 and 3:

   • Requirements 1 and 3: initial compliance "within the next 6 months after 31 October 2002 or at the expiry of the 12 calendar months interval as required by the previous issue of this Directive, whichever occurs first," and thereafter at intervals not to exceed six calendar months. That wording ties initial timing either to the date of the AD or to the expiry of the interval imposed by the previous AD. Operators must therefore check historical maintenance and previous AD compliance to determine whether the expiry of prior intervals occurs before the six‑month window.
   • Requirement 2: initial compliance "within the next 12 months after 31 October 2002 or at the expiry of the 4,000 flight hours or 24 calendar months interval as required by the previous issue of this Directive, whichever occurs first," and thereafter at intervals not to exceed 12 calendar months. This mixes flight‑hours and calendar time as triggers. Operators with high utilisation may find the 4,000 flight‑hour trigger first; low‑utilisation aircraft may find the 24‑month calendar trigger or the AD’s 12‑month window first.

   Gotcha: Reliance on "the previous issue of this Directive" means you must consult the prior AD text to compute the relevant expiries. Failure to do so risks missing an earlier expiry date.

2. Termination after modification. Note 1 states that compliance with Requirement 4 "constitutes terminating action for the actions required by Requirements 1, 2, and 3." Gotcha: that is a legal switch. After installing the locking devices, the recurring checks stop. Operators must ensure maintenance records and maintenance programmes are updated to show Requirement 4 has been completed; otherwise, auditors or inspectors may still expect recurring checks.

3. Hard deadline tied to aircraft age. Compliance 4 requires the modification "within the next 24 calendar months after 31 October 2002 or 15 years time‑since‑new of the aircraft, whichever occurs first." Gotcha: older aircraft with time‑since‑new close to 15 years may have a much earlier effective deadline than the 24‑month window, and operators must calculate which occurs first. It is not simply "24 months from effective date" for all aircraft.

4. SB revision and date specificity. Each requirement references a specific Fokker SB by number, revision and the date 17 June 2002 (except F50‑55‑008 is Revision 3 dated 17 June 2002). Gotcha: the AD requires compliance "in accordance with the Accomplishment Instructions" of the specified SB revisions. Using an incorrect SB revision or a different date may not meet the AD’s strict wording. Operators must obtain and use the exact SB revision cited.

5. The AD revokes Amendment 3. The opening paragraph says the CASA delegate "revokes Airworthiness Directive (AD) AD/F50/79 Amdt 3 and issues the following AD." Gotcha: because Amendment 4 revokes Amendment 3, operators must ensure the actions taken under Amendment 3 are reconciled with the new Amendment 4 obligations, particularly where Amendment 4 changes intervals or introduces new deadlines.

6. The AD does not specify who may perform the work or recordkeeping format. Gotcha: while the AD mandates the technical actions and references SB instructions, it does not state whether a particular licence category or maintenance organisation approval is required. Operators must rely on CAR 1998 maintenance authorisations and approved maintenance organisation rules to determine who may perform the work.

7. No penalties specified in the AD. Gotcha: the absence of penalties in the AD text does not mean there are none under CAR 1998. Operators should not assume non‑compliance is consequence‑free; the AD imposes obligations within the CAR 1998 legal framework, which governs enforcement and sanctions elsewhere.

8. Cross‑reference to overseas AD. Note 2 refers to Netherlands CAA AD 2000‑131/2. Gotcha: for operators with international operations or records, parallel obligations under other states’ ADs may apply. Cross‑jurisdictional differences in timing or required methods may create complex compliance schedules.

9. Differing treatment of rudder. The Background records that Amendment 2 changed the requirement for the rudder: "as a result of a recent evaluation which concluded that the rudder is of less airworthiness concern than originally envisaged, and the requirement for rudder removal to accomplish the task." Gotcha: earlier AD versions may have required rudder removal. Maintenance planners must confirm whether rudder removal is still necessary for their chosen SB method; the present AD’s SBs and Accomplishment Instructions should be followed.

10. Dependence on operator reporting history. The AD’s genesis is operator incident reports (elevator binding after landing; in‑flight vibration). Gotcha: the AD therefore addresses observed operational failure modes. Maintenance planners should be alert that the inspections are risk‑based around loose attachment screws and binding; absence of visible damage does not eliminate the AD obligations.

In short, the principal source of compliance error is misreading the timing triggers, failing to use the exact SB revisions and dates, failing to update maintenance records after completing the terminating modification, and not cross‑referencing prior ADs where initial intervals depend on the previous issue.

This section sets out a practical, source‑grounded checklist of steps, derived directly from the AD’s Requirements and Compliance paragraphs. The AD prescribes work "in accordance with the Accomplishment Instructions" of the specified Fokker Service Bulletins; compliance requires following those SB instructions precisely and observing the AD’s timing rules.

Step 1 , Determine applicability and aircraft status

• Confirm the aircraft model and serial number fall within the Applicability: Model F27 Mk 050, Mk 0502 and Mk 0604 aircraft, all serial numbers. If in doubt about model designation, consult the aircraft records.
• Determine the aircraft time‑since‑new and accumulated flight hours to compute which compliance trigger (calendar or flight hours) applies, particularly for Compliance 2 and Compliance 4.

Step 2 , Obtain the mandated Service Bulletins

• Acquire the exact Fokker Service Bulletins specified by the AD, including the exact revision and date listed:
  • F50‑55‑007 Revision 2, dated 17 June 2002 (elevator torque check) , Requirement 1.
  • F50‑55‑009 Revision 2, dated 17 June 2002 (rudder torque check) , Requirement 2.
  • F50‑57‑020 Revision 2, dated 17 June 2002 (aileron torque check) , Requirement 3.
  • F50‑55‑010 Revision 2, dated 17 June 2002 (rudder locking device installation) , Requirement 4(a).
  • F50‑57‑021 Revision 2, dated 17 June 2002 (aileron locking device installation) , Requirement 4(b).
  • F50‑55‑008 Revision 3, dated 17 June 2002 (elevator locking device installation) , Requirement 4(c).
• Note that the AD requires compliance "in accordance with the Accomplishment Instructions" of these SBs. Using a different SB revision without regulatory approval may not satisfy the AD.

Step 3 , Schedule and perform the initial checks

• For elevator (Requirement 1) and aileron (Requirement 3): perform the torque checks within six months after 31 October 2002 or at expiry of the prior 12‑month interval required by the previous issue of the Directive, whichever occurs first, and thereafter at intervals not exceeding six calendar months until Requirement 4 is completed.
• For rudder (Requirement 2): perform the torque check within 12 months after 31 October 2002 or at the expiry of the prior 4,000 flight hours or 24 calendar months interval required by the previous issue of the Directive, whichever occurs first, and thereafter at intervals not exceeding 12 calendar months until Requirement 4 is completed.
• Execute the torque checks and corrective action strictly following the Accomplishment Instructions in the relevant SB. If corrective action is necessary (for example, re‑torqueing or replacement of fasteners), perform the corrective measures as prescribed.

Step 4 , Repeat inspections until modification

• Continue to carry out the repetitive torque checks at the specified maximum intervals (6 months for elevator and aileron; 12 months for rudder) until the terminating modification has been completed on the aircraft.
• Keep clear records of each inspection, torque measurements, and any corrective actions taken, preserving the evidence needed to show compliance with the AD.

Step 5 , Plan and perform the terminating modification

• Schedule installation of the additional locking devices (Requirement 4) per the specified SBs and within the deadline in Compliance 4: "within the next 24 calendar months after 31 October 2002 or 15 years time‑since‑new of the aircraft, whichever occurs first."
• Use the Accomplishment Instructions in the cited SBs (F50‑55‑010 Rev 2, F50‑57‑021 Rev 2, F50‑55‑008 Rev 3) to perform the modification. Ensure that maintenance personnel and facilities performing the work are authorised under CAR 1998 provisions to carry out such modifications.

Step 6 , Update maintenance programme and records

• Once Requirement 4 has been accomplished, treat that action as terminating for Requirements 1-3, per Note 1. Update the aircraft maintenance programme and maintenance records to reflect that the additional locking devices have been installed and that the repetitive torque checks are no longer required.
• Retain documentation that shows compliance with Requirement 4 , service bulletin compliance data, who performed the work, date, parts installed, and any certification paperwork required by CAR 1998.

Step 7 , Cross‑reference prior AD and related CAA AD

• For initial scheduling and interval calculations tied to "the previous issue of this Directive," consult the prior AD texts to determine when the previous intervals expire. The AD requires aligning initial checks with the earlier schedule where applicable.
• Note the reference to Netherlands CAA AD 2000‑131/2 (Note 2). If operating internationally, ensure any corresponding obligations under foreign ADs are understood and met.

Step 8 , Preserve traceability and regulatory evidence

• Maintain clear traceability that all actions were performed "in accordance with the Accomplishment Instructions" of the specified SBs, noting revision numbers and dates.
• Keep records of torque values and corrective work where performed, and document the parts and locking devices installed during the terminating modification.

Step 9 , Anticipate inspection and enforcement checks

• Be prepared to present maintenance records showing compliance with the AD during regulatory inspections. Although the AD does not set out penalties, the AD’s obligations exist within the CAR 1998 framework and regulators will expect demonstrable compliance.

Step 10 , Seek clarification or approvals if necessary

• The AD does not specify alternative methods of compliance in its text. If an operator wishes to propose an alternate technical solution or use a different SB revision, they should follow the appropriate CASA procedures (outside the AD text) to obtain approval or an accepted alternative method of compliance. The AD itself does not detail that route.

In practical terms, compliance requires three linked actions: (a) precise reading of the AD timing language and cross‑reference to prior AD intervals where relevant; (b) performance of torque checks and corrective actions exactly as prescribed by the listed SB Accomplishment Instructions; and (c) completion of the terminating modification within the prescribed time‑since‑new or calendar deadline and proper recordation of that work so the recurring checks can be removed from the maintenance regime.

By following the steps above and retaining documentary evidence of SB compliance and timing, operators will meet the AD’s requirements as stated in AD/F50/79 Amdt 4.