{"id":"F2006B04080","name":"AD/BEECH 60/19 - Moisture Barrier Fuselage Station 306.421","slug":"ad-beech-60-19-moisture-barrier-fuselage-station-306-421","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43746,"registerId":"commonwealth-F2006B04080-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 60/19 - Moisture Barrier Fuselage Station 306.421","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)  Beechcraft 60 (Duke) Series Aeroplanes\n\n \n\nAD/BEECH 60/19 Moisture Barrier Fuselage Station 306.421 11/72\n\nApplicability: All models.\n\n \n\nRequirement: To prevent possible interference with elevator movement, accomplish the following:\n\n \n\nStarting at the cutout for the elevator bell crank, slit the moisture barrier vertically upward using a knife, razor blade or similar tool. Extend this cut through the “velcro” strip which attaches the moisture barrier to the front spar of the horizontal stabiliser.\n\n \n\nNote: In making the slit do not damage the spar.\n\n \n\nCompliance: Within 25 hours’ time in service after 3 November 1972 unless already accomplished.\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":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive's scope is a narrowly prescribed physical modification to the moisture barrier intended to prevent possible elevator interference (Requirement). The text applies to all Beechcraft 60 models and sets a single, short compliance deadline; it does not expand or narrow that instruction compared with the stated purpose in the instrument itself. No additional obligations, ongoing inspections, or broader structural changes are introduced in the text (Applicability; Requirement; Compliance; Note)."},"complexity_factors":["Simple, single-step physical action (cutting a moisture barrier) reduces procedural complexity (Requirement).","Short compliance window (25 hours’ time in service) creates scheduling urgency but not technical complexity (Compliance).","High operator discretion on tools and technique increases execution variability and risk of spar damage (Requirement; Note).","No follow-up inspection, acceptance criteria, or restoration instructions specified increases uncertainty about verification and long-term effect on the moisture barrier (Requirement; Note).","Applicability to all models is broad but does not introduce model-specific variation in the text (Applicability)."],"plain_english_summary":"What this directive does (mechanics)\n\n- Applies to: All Beechcraft 60 (Duke) series aeroplanes (Applicability).\n- The required physical change: beginning at the existing cutout for the elevator bell crank, make a vertical slit upward in the moisture barrier using a knife, razor blade or similar tool. Extend that cut through the Velcro strip that fastens the moisture barrier to the front spar of the horizontal stabiliser (Requirement). The directive warns not to damage the spar while cutting (Note).\n- Timing: the work must be done within 25 hours’ time in service after 3 November 1972, unless it has already been done (Compliance).\n\nWhy the directive is issued (stated purpose)\n\n- The directive states its purpose explicitly: to prevent possible interference with elevator movement (Requirement). That is the claimed safety rationale for creating the slit.\n\nPractical consequences, who pays and who decides\n\n- Who pays and arranges the work: the aircraft owner/operator must cause the work to be done because the applicability covers all aircraft and the compliance clause sets the deadline (Applicability, Compliance). The actual cutting is a maintenance action that will normally be carried out by maintenance personnel qualified to work on the aircraft.\n- Decision discretion: the directive allows the choice of cutting implement (“knife, razor blade or similar tool”) and leaves the exact execution to the person performing the task (Requirement). It does not prescribe a particular repair procedure beyond making the slit.\n\nCosts, incentives and trade-offs\n\n- Direct cost and time: the physical task is a one-off, manual cut. No replacement parts are specified; the material and labour cost are therefore likely to be small. The directive gives a short compliance window (25 hours’ flight time), which creates an incentive to schedule the work promptly so the aircraft remains lawful to operate (Compliance).\n- Compliance burden: there is an operational burden to locate the cutout, perform the cut without damaging the spar, and record compliance in maintenance records. The instrument does not specify any follow-up inspections, sealing, or restoration of the moisture barrier after cutting.\n- Implementation risk and discretion: the only explicit safety warning is not to damage the spar (Note). Because the tool and exact technique are left to the maintenance person, there is discretion about method and care; improper execution risks damaging the spar (Note) or otherwise altering the moisture barrier. The directive does not specify acceptance criteria for the cut or require verification beyond performing the cut.\n\nOperational effects on aircraft and operators\n\n- The action modifies the moisture barrier by creating a vertical slit through the barrier and its Velcro attachment. The directive’s stated aim is to remove a possible source of elevator interference (Requirement). The directive does not add ongoing inspection or maintenance steps tied to the changed barrier.\n\nSummary statement\n\n- Mechanically, the directive requires a simple, specified cut in the moisture barrier at a named location. The stated rationale is to prevent possible interference with elevator movement. The owner/operator bears the cost and responsibility to schedule and perform the work within the short compliance window. The instrument leaves the choice of tool and technique to maintenance personnel, warns against spar damage, and does not prescribe follow-up restoration or inspection requirements (Applicability; Requirement; Note; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-purpose airworthiness directive from 1972 addressing one specific mechanical defect in one aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific mechanical modification with clear physical instructions","Only 2 defined applicability criteria (aircraft model and 'all models')","Simple conditional: compliance required within 25 hours time in service after fixed date, with single exception ('unless already accomplished')","No cross-references to other legislation or regulations beyond basic citation","One cautionary note embedded in requirement, not nested exceptions","Total length: approximately 150 words of substantive content"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of **Beechcraft 60 (Duke) series aeroplanes** to make a physical modification to prevent a dangerous safety problem. Specifically, they must cut a vertical slit in a moisture barrier (a protective layer inside the aircraft) near the tail section. This prevents the moisture barrier from interfering with the **elevator** — the movable part of the tail that controls whether the plane pitches up or down.\n\n**Who it affects:**\nAnyone who owns, operates, or maintains any model of the Beechcraft 60 (Duke) aircraft.\n\n**Why it matters:**\nIf the moisture barrier isn't modified, it could physically block the elevator from moving properly. This could cause loss of pitch control — meaning the pilot might not be able to make the plane climb or descend safely, potentially leading to a crash.\n\n**What must be done:**\n- Make a vertical cut in the moisture barrier starting at the elevator bell crank (a mechanical linkage) cutout\n- Extend the cut through the Velcro strip attaching the barrier to the horizontal stabiliser's front spar (the fixed wing at the tail)\n- **Important:** Don't damage the spar (the main structural beam) while cutting\n- **Deadline:** Within 25 hours of flight time after 3 November 1972, unless already done\n\n**Key terms explained:**\n- **Elevator:** The hinged part of the tail that makes the plane go up or down\n- **Fuselage Station 306.421:** A specific location measurement along the aircraft's body (like a coordinate system for planes)\n- **Time in service:** Actual flying hours, not just calendar time"}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-60-19-moisture-barrier-fuselage-station-306-421","history":"/api/acts/ad-beech-60-19-moisture-barrier-fuselage-station-306-421/history","analysis":"/api/acts/ad-beech-60-19-moisture-barrier-fuselage-station-306-421/analysis","conflicts":"/api/acts/ad-beech-60-19-moisture-barrier-fuselage-station-306-421/conflicts","importantCases":"/api/acts/ad-beech-60-19-moisture-barrier-fuselage-station-306-421/important-cases","documents":"/api/acts/ad-beech-60-19-moisture-barrier-fuselage-station-306-421/documents"}}