{"id":"F2006B04192","name":"AD/BEECH 77/2 - Rudder and Rudder Trim Tab","slug":"ad-beech-77-2-rudder-and-rudder-trim-tab","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43946,"registerId":"commonwealth-F2006B04192-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 77/2 - Rudder and Rudder Trim Tab","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-description: CASA Airworthiness Directive\nmeta-generator: Aspose.Words for .NET 22.10.0\nmeta-keywords: Issue 4/1980,Aircraft below 5700 kg,Beechcraft 77 (Skipper) Series Aeroplanes,Rudder and Rudder Trim Tab,2\ntitle: Airworthiness Directive - AD/BEECH 77/2 - Rudder and Rudder Trim Tab\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 77 (Skipper) Series Aeroplanes\n\n \n\nAD/BEECH 77/2 Rudder and Rudder Trim Tab 4/80\n\nApplicability: All model 77 with S/Nos. WA-1 to WA-76. Requirement:  Action in accordance with Beechcraft SI No. 1116. Compliance:               Within 25 hours’ time in service after 11 march 1980.\n\nBackground: There is a possibility of water accumulating in the rudder and/or trim tab.\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 discrete, targeted safety directive addressing a specific airworthiness concern on a specific aircraft type. It has not expanded beyond its original purpose of mandating a manufacturer service bulletin to prevent water ingress in control surfaces."},"complexity_factors":["Extremely short document — approximately 150 words total","Only one substantive requirement referencing an external technical document (Beechcraft SI No. 1116)","Simple applicability clause limited to specific serial number range","Single compliance deadline with straightforward calculation (25 hours time in service after fixed date)","No defined terms section, no cross-references to other legislation beyond the enabling regulation (CAR 1998 Part 39)","No conditional logic, exceptions, or nested provisions"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety notice issued by the Civil Aviation Safety Authority (CASA) that requires aircraft owners to fix a specific problem.\n\n**What it does:** It orders owners of certain Beechcraft 77 \"Skipper\" aeroplanes (specifically serial numbers WA-1 through WA-76) to inspect and address a water accumulation problem in the rudder and rudder trim tab. Water getting into these control surfaces can cause corrosion or freezing, which could jam the controls and make the aircraft unsafe to fly.\n\n**What owners must do:** Follow the instructions in Beechcraft Service Instruction No. 1116. This is a technical document from the manufacturer detailing exactly how to inspect, drain, seal, or repair the affected parts.\n\n**When it must be done:** Within 25 hours of flying time after 11 March 1980. So if your plane had flown 100 hours by that date, you had until 125 total hours to comply.\n\n**Who it affects:** Anyone operating or maintaining these specific Beechcraft 77 aircraft in Australia. Non-compliance means the aircraft cannot legally fly.\n\n**Why it matters:** Rudder control is essential for safe flight. Water accumulation could lead to control failure, potentially causing loss of the aircraft and lives. ADs are legally binding — ignoring them grounds the aircraft."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive targets a specific risk (water accumulation in rudder/trim tab) on a defined set of airframes and requires action per Beechcraft SI No. 1116 within a short deadline. There is no text in the instrument that expands or narrows the set of affected aircraft or the mandated corrective approach beyond the stated Applicability and Requirement, so the scope remains as presented (Applicability; Requirement; Compliance; Background)."},"complexity_factors":["Very narrow applicability: applies only to Beechcraft 77 serial numbers WA-1 to WA-76 (Applicability).","Single corrective action is delegated to an external document (Beechcraft SI No. 1116), requiring access to and interpretation of that service instruction (Requirement).","Short compliance window (25 hours time in service after 11 March 1980) increases urgency and scheduling pressure (Compliance).","Operational impacts depend on availability of parts and qualified maintenance personnel; those practical constraints add modest implementation complexity (Requirement; Compliance).","Administrative tasks: identifying affected aircraft, recording compliance, and liaising with regulators increase minor procedural complexity (Applicability; Compliance)."],"plain_english_summary":"- What this instrument does mechanically:\n  - Orders operators/owners of certain Beechcraft 77 (Skipper) aeroplanes to carry out the work described in Beechcraft Service Instruction No. 1116. (Requirement)\n  - Requires that the work be completed within 25 hours time in service after 11 March 1980. (Compliance)\n\n- Who it affects:\n  - All Beechcraft 77 aircraft with serial numbers WA-1 through WA-76. (Applicability)\n  - The people who pay for and perform the work are the aircraft owners/operators and their maintenance organisations. (Requirement; Compliance)\n\n- Why it matters (official reason and practical effect):\n  - The stated reason is the possibility that water can accumulate in the rudder and/or the rudder trim tab. (Background)\n  - Mechanically, the directive forces a mandatory inspection/modification (as specified in SI No. 1116) to address that water accumulation risk. Completing the instruction changes maintenance requirements for the specified aircraft until the condition is resolved as set out in the service instruction. (Requirement)\n\n- Practical costs, incentives and trade-offs:\n  - Direct costs fall on owners/operators: labour, any replacement parts, and aircraft downtime while the work is done. (Requirement; Compliance)\n  - The directive creates an incentive for operators to schedule the required work quickly because of the short compliance window (25 hours TIS). (Compliance)\n  - The text delegates the technical detail to Beechcraft SI No. 1116; operators must obtain and follow that document, which is an additional compliance step. (Requirement)\n\n- Implementation, compliance burden and risks:\n  - Compliance requires identifying affected airframes by serial number and arranging maintenance to the specification in SI No. 1116. (Applicability; Requirement)\n  - Risk factors for implementation include availability of the service instruction, parts or qualified maintenance personnel, and potential temporary grounding of aircraft pending completion. (Requirement; Compliance)\n  - Enforcement and oversight are exercised through the Airworthiness Directive mechanism; the AD sets the mandatory action and deadline but relies on the service instruction for technical steps. (Requirement)\n\n- Who decides and what changes in behaviour:\n  - The Civil Aviation Safety Authority issued the directive; affected owners/operators decide how and when to schedule the work to meet the 25-hour compliance period. (Applicability; Requirement; Compliance)\n  - The immediate behavioural change required is to obtain SI No. 1116 and carry out the described work within the specified timeframe. (Requirement; Compliance)\n\nCited source lines: Applicability; Requirement; Compliance; Background."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-77-2-rudder-and-rudder-trim-tab","history":"/api/acts/ad-beech-77-2-rudder-and-rudder-trim-tab/history","analysis":"/api/acts/ad-beech-77-2-rudder-and-rudder-trim-tab/analysis","conflicts":"/api/acts/ad-beech-77-2-rudder-and-rudder-trim-tab/conflicts","importantCases":"/api/acts/ad-beech-77-2-rudder-and-rudder-trim-tab/important-cases","documents":"/api/acts/ad-beech-77-2-rudder-and-rudder-trim-tab/documents"}}