{"id":"F2006B09779","name":"AD/F28/43 Amdt 1 - Wing Flap Mechanical Actuators - Inspection","slug":"ad-f28-43-amdt-1-wing-flap-mechanical-actuators-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54693,"registerId":"commonwealth-F2006B09779-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F28/43 Amdt 1 - Wing Flap Mechanical Actuators - Inspection","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Fokker F28 Series Aeroplanes\n\n \n\nAD/F28/43\n\nAmdt 1\n\n\nWing Flap Mechanical Actuators - Inspection 3/82\n\n \n\nApplicability: All models with flap actuators modified to Menasco SBs 27-63 or 27-66 but NOT modified to Menasco SB 27-81.\n\n \n\nDocument: 1. Fokker SB No. F28/27-137; or\n\n \n\n2. RLD AD. BLA 80-08-27.\n\n \n\nCompliance: As detailed in requirement document.\n\n \n\nThis Directive has been raised in issue to include reference to Menasco SB No. 27-81, which introduces an improved steel ball return tube no longer subject to repetitive inspection.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a minor amendment to an existing Airworthiness Directive. The scope remains unchanged — it still governs inspection requirements for wing flap actuators on Fokker F28 aircraft. The amendment simply updates the applicability to account for a newer technical standard (Menasco SB 27-81) that eliminates the need for repetitive inspections."},"complexity_factors":["Extremely short document (under 200 words)","Only 3 defined applicability criteria (specific service bulletin modifications)","Single compliance requirement referring to external documents","No nested conditional logic or exceptions beyond the applicability clause","No cross-references to other legislation or regulations within the text itself"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) for **Fokker F28 series aircraft**.\n\n**What it does:**\nIt requires airlines and aircraft operators to inspect the **wing flap mechanical actuators** — the machinery that extends and retracts the flaps on the wings during takeoff and landing.\n\n**Who it affects:**\nOperators of Fokker F28 planes that have had their flap actuators modified according to two specific service bulletins (Menasco SB 27-63 or SB 27-66) **but have NOT** been upgraded to a newer standard (Menasco SB 27-81).\n\n**Why it matters:**\nFlaps are critical for safe takeoff and landing. This directive was updated (Amendment 1) to clarify that aircraft upgraded with a specific improved part (a steel ball return tube) no longer need repeated inspections, while those without the upgrade still do. This helps operators know which planes need ongoing maintenance checks and which are exempt.\n\n**Key point:** If your Fokker F28 has the old modification (SB 27-63 or 27-66) but not the new one (SB 27-81), you must keep inspecting the flap actuators as originally required."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The amendment changes the AD's scope by introducing reference to Menasco SB No. 27-81 and stating that actuators modified to SB 27-81 are no longer subject to repetitive inspection. Previously the AD applied to actuators modified to Menasco SBs 27-63 or 27-66; the amendment excludes those actuators if they have subsequently been modified to SB 27-81, thereby narrowing the set of aircraft/components subject to repetitive inspection. (Applicability; final paragraph.)"},"complexity_factors":["Narrow technical applicability limited to flap actuators modified to specific Menasco Service Bulletins (27-63, 27-66, 27-81) (\"Applicability\").","Reliance on external technical documents (Fokker SB F28/27-137; RLD AD. BLA 80-08-27) for the substantive inspection procedures and intervals (\"Document\"; \"Compliance\").","Ambiguity in on-face AD about exact procedures and intervals because the AD defers details to the referenced documents (\"Compliance: As detailed in requirement document.\").","Operational requirement to verify modification status for each actuator (need to distinguish SB 27-81 from 27-63/66), which increases implementation complexity despite the short AD text (\"Applicability\"; final paragraph).","Regulatory amendment alters scope by reference to a specific modification (SB 27-81) rather than by directly prescribing inspection cessation criteria, requiring cross-referencing and record checks (final paragraph)."],"plain_english_summary":"What this directive changes, mechanically:\n\n- It changes the inspection requirement that applies to the wing flap mechanical actuators on Fokker F28 series aeroplanes by making a specific modification (Menasco SB No. 27-81) the trigger for exclusion from repetitive inspection. In short: actuators modified to Menasco SB 27-81 are no longer subject to the repetitive inspection called out by the AD; actuators modified only to Menasco SBs 27-63 or 27-66 remain within the AD's applicability. (See: \"Applicability\" and final paragraph.)\n\nWhat the document says and why it matters:\n\n- The AD applies to \"All models with flap actuators modified to Menasco SBs 27-63 or 27-66 but NOT modified to Menasco SB 27-81.\" (Applicability.) That defines precisely which aircraft are covered.\n- The AD requires compliance \"As detailed in [the] requirement document.\" The requirement document is one of: Fokker SB No. F28/27-137 or RLD AD. BLA 80-08-27. (Document; Compliance.) Those referenced documents contain the technical inspection steps and intervals the AD enforces.\n- The AD states it was reissued to \"include reference to Menasco SB No. 27-81, which introduces an improved steel ball return tube no longer subject to repetitive inspection.\" That is the stated reason for amending the AD: the SB 27-81 modification is described as an improvement that removes the need for repetitive inspection for that component. (Final paragraph.)\n\nWho pays and who decides:\n\n- The directive is issued under the Commonwealth Civil Aviation Safety Authority schedule of Airworthiness Directives; the regulator is the decision-maker that issued the AD. (Header and schedule reference.)\n- The AD requires compliance \"as detailed in [the] requirement document.\" That places the operational responsibility on aircraft operators/maintenance organisations to follow the inspection steps and intervals in the referenced documents, so they will bear the direct compliance costs (labour, downtime, parts) specified there. (\"Compliance: As detailed in requirement document.\" and \"Document\" list.)\n\nHow behaviour changes and what private agents must do:\n\n- Operators of F28 aeroplanes must identify whether their flap actuators have been modified to Menasco SB 27-63 or 27-66, or to Menasco SB 27-81. If modified to SB 27-63 or 27-66 (and not to 27-81), the AD's inspection requirements in the referenced documents remain applicable. If modified to SB 27-81, the repetitive inspection requirement no longer applies per this AD. (Applicability; final paragraph.)\n\nCosts, incentives, trade-offs and compliance burden (source-grounded):\n\n- The AD reduces the repeating inspection burden for aircraft that have the SB 27-81 modification by removing them from the repetitive-inspection requirement (final paragraph). That creates an incentive for operators to adopt the SB 27-81 modification if they value lowering inspection frequency, subject to the costs of performing the modification (the AD does not state those costs).\n- The AD relies on external technical documents for the detailed inspection steps and intervals (Fokker SB F28/27-137 or RLD AD. BLA 80-08-27). Because the substantive requirements are in those documents, determining exact compliance effort requires consulting them. (Document; Compliance.)\n- The directive transfers some implementation complexity onto operators/maintenance organisations: they must verify modification status (27-63/66 vs 27-81) and follow the referenced documents. The AD text does not itself list inspection intervals or procedures, so operators must obtain and follow the specified SB/AD documents. (Applicability; Document; Compliance.)\n\nImplementation risk and bureaucratic discretion:\n\n- The AD's effect depends on correct identification and record-keeping of which Menasco SB(s) have been applied to each actuator. Misidentification could lead to missed inspections if an actuator is wrongly assumed to be amended by SB 27-81. The AD text does not specify verification procedures. (Applicability; final paragraph.)\n- The regulator amended the AD to add reference to SB 27-81, changing the set of parts/aircraft subject to repetitive inspection. That is an exercise of regulatory discretion to exempt items that meet the new modification standard. (Final paragraph.)\n\nConcentrated benefits, diffuse costs and substitution effects (source-grounded):\n\n- The immediate benefit of reduced inspection frequency accrues to operators whose actuators carry SB 27-81 (a concentrated group). The AD text does not set out broader economic effects or quantify costs saved. (Final paragraph.)\n- The AD creates a substitution possibility: operators may choose between continuing repetitive inspections (if they retain 27-63/66) or installing the SB 27-81 modification to avoid repetitive inspection, depending on relative costs. The AD text does not quantify those trade-offs; it only establishes the regulatory outcome tied to the modification. (Applicability; final paragraph.)\n\nWhere to find the technical requirements:\n\n- The AD points to two documents for detailed requirements: Fokker SB No. F28/27-137 or RLD AD. BLA 80-08-27. Operators must consult those documents for procedural and timing details. (Document; Compliance.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-f28-43-amdt-1-wing-flap-mechanical-actuators-inspection","history":"/api/acts/ad-f28-43-amdt-1-wing-flap-mechanical-actuators-inspection/history","analysis":"/api/acts/ad-f28-43-amdt-1-wing-flap-mechanical-actuators-inspection/analysis","conflicts":"/api/acts/ad-f28-43-amdt-1-wing-flap-mechanical-actuators-inspection/conflicts","importantCases":"/api/acts/ad-f28-43-amdt-1-wing-flap-mechanical-actuators-inspection/important-cases","documents":"/api/acts/ad-f28-43-amdt-1-wing-flap-mechanical-actuators-inspection/documents"}}