{"id":"F2009L00884","name":"AD/F50/98 Amdt 1 - MLG Sliding Member End-stop","slug":"ad-f50-98-amdt-1-mlg-sliding-member-end-stop","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":78176,"registerId":"commonwealth-F2009L00884-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Fokker F50 (F27 Mk 50) Series Aeroplanes","sectionType":"division","heading":"Fokker F50 (F27 Mk 50) Series Aeroplanes","content":"### Fokker F50 (F27 Mk 50) Series Aeroplanes\n\n| AD/F50/98 Amdt 1 | MLG Sliding Member End-stop | 4/2009 |\n| ---------------- | --------------------------- | ------ |\n\n| Applicability: | Model F27 Mark 050, Mark 0502, and Mark 0604 aircraft, all serial numbers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the requirements of EASA AD 2009-0018.Note: Fokker Services Service Bulletin SBF50-32-039 original issue, or later EASA approved revision, and Messier Dowty Service Bulletin SB F50-32-62 original issue, or later EASA approved revision, refer.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of9 April 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n|                | This Amendment becomes effective on 9 April 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background:    | A report was received of an over-extended main landing gear sliding member after landing. Investigation revealed that an end stop had unscrewed, and that no lockwire was present on the two lockbolts which hold the end stop. This condition, if not corrected, could lead to structural damage of the main gear and loss of control of the aircraft during the landing roll.Amendment 1 is issued in response to a new EASA AD. This EASA AD supersedes the previous CAA-NL AD because a change in EASA AD policy now allows the issue of Mandatory Continuing Airworthiness action to require correction of unsafe conditions, resulting from production and/or maintenance deficiencies. There is no change to the technical requirements of this Directive. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n24 February 2009","sortOrder":0},{"sectionNumber":"AD/F50/98 Amdt 1","sectionType":"part","heading":"AD/F50/98 Amdt 1","content":"## AD/F50/98 Amdt 1","sortOrder":1},{"sectionNumber":"MLG Sliding Member End-stop","sectionType":"part","heading":"MLG Sliding Member End-stop","content":"## MLG Sliding Member End-stop","sortOrder":2},{"sectionNumber":"4/2009","sectionType":"part","heading":"4/2009","content":"## 4/2009","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment explicitly states there is no change to the technical requirements. The scope remains limited to the specific landing gear end-stop issue on Fokker F50 aircraft. The amendment only changes the regulatory instrument under which the directive is issued (from CAA-NL to EASA), not the substantive safety action required."},"complexity_factors":["Very short document (approximately 250 words of substantive content)","Only 3 defined applicability criteria (specific aircraft models)","Single requirement referencing external documents (EASA AD and two Service Bulletins)","No nested conditional logic or exceptions","No internal cross-references within the document itself","Straightforward compliance date structure"],"plain_english_summary":"This AD mandates inspection and corrective action on the main landing gear end-stop of Fokker F50 Mark 050, 0502 and 0604 aircraft after reports of an end‑stop unscrewing (due to unsecured lockbolts), which can damage gear and risk loss of control on landing. Owners/operators must follow EASA AD 2009‑0018 and the Fokker SBF50‑32‑039 and Messier Dowty SB F50‑32‑62 service bulletins. Effective 9 April 2009; this amendment only updates the legal basis to EASA—technical requirements remain unchanged."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The amendment does not expand the technical scope of the directive. It adopts a new EASA AD as the mandatory requirement and realigns the legal basis (allowing Mandatory Continuing Airworthiness action to require correction of production/maintenance deficiencies), but explicitly states there is no change to the technical requirements. Therefore the action is procedural/legal in nature rather than an expansion of substantive obligations."},"complexity_factors":["Single substantive requirement delegated to EASA AD 2009-0018 (external document)","References two manufacturer service bulletins (Fokker SBF50-32-039 and Messier Dowty SB F50-32-62) with allowance for later EASA‑approved revisions","Applicability covers three model variants (Mark 050, 0502, 0604) and all serial numbers (broad within model line)","Compliance timing and technical steps are not spelled out in the AD text itself but by the external EASA AD/service bulletins (dependency on external documents)","Administrative change (revised effective date 9 April 2009) and background explanation, but no nested exceptions or multiple conditional branches","Short document with low number of internal defined terms and no cross‑references to other domestic legislation"],"plain_english_summary":"**What this directive does (mechanically)**\n\n- This is an airworthiness directive (AD) that requires operators of certain Fokker F50 (F27 Mk 50) series aeroplanes to carry out the inspections and corrective work described in EASA AD 2009-0018.  The AD points you to two service bulletins for the technical steps: Fokker Services SBF50-32-039 and Messier Dowty SB F50-32-62 (use the original issue or any later EASA‑approved revision).\n- The AD applies to Model F27 Mark 050, Mark 0502 and Mark 0604 aircraft, all serial numbers.  The AD became effective 9 April 2009.\n\n**Who is affected**\n\n- Aircraft owners/operators of the listed Fokker F50 models.  Their maintenance organisations (MROs) and any suppliers of replacement parts are also affected because they carry out the inspections and repairs.\n\n**What you must do**\n\n- Follow the compliance requirements set out in EASA AD 2009-0018 and the referenced service bulletins.  In practice that means inspecting the main landing gear (MLG) sliding member end-stop, checking the end-stop and its lockbolts/lockwire, and carrying out any corrective actions (repair/replace/secure fasteners) that the service bulletins require.\n- Record compliance in the aircraft maintenance log as required by normal continuing airworthiness practice.\n\n**Why it matters (safety risk and trigger for the AD)**\n\n- A report found an over‑extended MLG sliding member after landing where an end-stop had unscrewed and the two lockbolts had no lockwire.  If uncorrected, that condition could cause structural damage to the main gear and loss of control during the landing roll.  The AD addresses that specific unsafe condition.\n\n**Regulatory mechanics and scope**\n\n- The AD does not add new technical work beyond the EASA AD and the service bulletins; it adopts those documents as mandatory.  The amendment reflects a change in regulatory policy (EASA now allows mandatory action to require correction of unsafe conditions arising from production or maintenance deficiencies), but the technical instructions remain the same.\n\n**Who pays, who decides, and what changes in behaviour**\n\n- Who pays: aircraft operators (or their insurers) pay for labour, parts and any aircraft downtime required to perform inspections and repairs. Maintenance providers incur labour and scheduling costs.\n- Who decides: the Civil Aviation Safety Authority (by issuing this AD) enforces the requirement, but the technical content and compliance times are set by the referenced EASA AD and service bulletins.  The AD also allows later EASA‑approved revisions of the service bulletins to be used.\n- Behavioural change: operators must schedule and perform the specified inspections and corrective work on affected aircraft, and maintenance organisations must implement the fixes and maintain records.\n\n**Costs, incentives and trade‑offs**\n\n- Direct costs are concentrated on the affected operators and their maintenance providers: technician hours, possible replacement parts, and aircraft downtime.  Those costs are one‑off per affected aircraft unless repeated inspections are required.\n- Benefits (concentrated on flying safety for that aircraft and its occupants) are the reduction in risk of MLG failure or loss of control during landing roll.\n- Suppliers of parts and maintenance services may see increased business from required repairs—this is an expected market effect from mandatory maintenance.\n- The AD delegates technical detail and compliance timing to external documents (EASA AD and service bulletins). That reduces ambiguity in technical work but imposes a dependency on those external documents for exact scope and timing.\n\n**Implementation and compliance risk**\n\n- Implementation risk is chiefly operational: if operators delay or incorrectly perform the work, the unsafe condition remains.  The AD’s legal force means regulators can require compliance; the AD itself gives no technical leeway beyond using EASA‑approved revisions of the service bulletins.\n- Because the AD covers all serial numbers of the listed models, the requirement is broad within the model line but limited to those aircraft types.\n\n**Source claim and evaluation**\n\n- The AD’s stated purpose is to remove the unsafe condition reported (unscrewed end‑stop and missing lockwire).  That purpose is supported by the background incident described and by the mandatory adoption of the EASA AD and service bulletin instructions.  The amendment’s administrative change (aligning with EASA policy to allow Mandatory Continuing Airworthiness action for production/maintenance deficiencies) is procedural; it does not change the technical tasks operators must perform.\n\n"},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-98-amdt-1-mlg-sliding-member-end-stop","history":"/api/acts/ad-f50-98-amdt-1-mlg-sliding-member-end-stop/history","analysis":"/api/acts/ad-f50-98-amdt-1-mlg-sliding-member-end-stop/analysis","conflicts":"/api/acts/ad-f50-98-amdt-1-mlg-sliding-member-end-stop/conflicts","importantCases":"/api/acts/ad-f50-98-amdt-1-mlg-sliding-member-end-stop/important-cases","documents":"/api/acts/ad-f50-98-amdt-1-mlg-sliding-member-end-stop/documents"}}