{"id":"F2006B11252","name":"AD/M20/47 - Rudder Static Balance","slug":"ad-m20-47-rudder-static-balance","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56972,"registerId":"commonwealth-F2006B11252-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/M20/47 - Rudder Static Balance","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nMooney M20 Series Aeroplanes\n\nAD/M20/47 Rudder Static Balance 6/92 TX\n\nApplicability: Model M20J with S/Nos. 24-3201, 24-3218 to 24-3238, 24-3240 to 24-3250 and 24-\n\n3252 to 24-3256.\n\nRequirement: 1. Fabricate and install in clear view of the pilot a placard stating “MAXIMUM GROSS WEIGHT REDUCED TO 1243 kg (2740 lb)”.\n\n2. Inspect the aircraft to ensure that the rudder static balance is within the required limits in accordance with paras. 1 to 3 of the instructions section of Mooney Aircraft Corporation Service Bulletin M20-252 dated 6 April 1992. After inspection and rectification as necessary, remove placard.\n\nNote: FAA Telegraphic AD 92-08-15 refers.\n\nCompliance: 1. Before further flight after 15 April 1992.\n\n2. Within 15 hours time in service after 15 April 1992.\n\nBackground: FAA advise that the limitations are necessary to prevent rudder imbalance, leading to aerodynamic problems and possible loss of control.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD sets a temporary operational restriction (reduced maximum gross weight via a pilot-visible placard) and requires inspection and any necessary rectification of rudder static balance for the listed M20J serial numbers. The text delegates technical detail to the referenced Mooney Service Bulletin and prescribes specific deadlines. There is no indication in the AD text that the scope was altered from its original stated measures; it confines action to the listed serial numbers and the two required steps (Requirement 1–2; Applicability; Compliance 1–2)."},"complexity_factors":["Narrow applicability to specific M20J serial numbers reduces breadth but requires checking serial numbers (Applicability).","Two-step prescriptive action: immediate placard+weight restriction, then inspection/rectification per manufacturer SB (Requirement 1–2).","Short compliance window (placard before next flight after 15 April 1992; inspection within 15 hours TIS) concentrates logistical effort (Compliance 1–2).","Technical compliance depends on external document (Mooney Service Bulletin M20-252 paras. 1–3) — following that SB may require specialised skills and parts (Requirement 2).","No alternative compliance route or discretionary relief is provided in the AD text, so operators must follow the specified steps (Requirement 2)."],"plain_english_summary":"What this instrument does\n\n- Applies to Mooney M20J aeroplanes with the specific serial numbers listed in the Applicability clause. (Applicability)\n- Requires the owner/operator to make and display, in clear view of the pilot, a placard reading: “MAXIMUM GROSS WEIGHT REDUCED TO 1243 kg (2740 lb)”. (Requirement 1)\n- Requires the owner/operator to inspect the rudder static balance and, if necessary, make repairs so the rudder balance meets the limits set out in paragraphs 1–3 of the Instructions section of Mooney Aircraft Corporation Service Bulletin M20-252 dated 6 April 1992. After inspection and any rectification, the placard is to be removed. (Requirement 2)\n- Sets timing: the placard must be installed before the next flight after 15 April 1992; the inspection/rectification must be completed within 15 hours time-in-service after 15 April 1992. (Compliance 1–2)\n- Records the FAA’s stated reason that the measures are to prevent rudder imbalance and the aerodynamic problems and possible loss of control that imbalance could cause. (Background; Note: FAA Telegraphic AD 92-08-15 refers.)\n\nWho is affected and who decides\n\n- Affected parties: the registered owner/operator of the listed Mooney M20J aeroplanes. (Applicability)\n- Decision / action required from the owner/operator: fabricate and install the placard, arrange and carry out the inspection per the referenced service bulletin, perform any corrective work required, and remove the placard once the aircraft meets the balance limits. (Requirement 1–2; Compliance 1–2)\n- The regulator (the AD issuer) sets the mandatory steps and deadlines; the operator pays for and executes the physical work. (Requirement 1–2; Compliance 1–2)\n\nKey operational mechanics, costs and trade-offs (source-cited)\n\n- Immediate operational limit: while the placard is displayed the aircraft must operate subject to a reduced maximum gross weight of 1243 kg (2740 lb). That reduces allowable payload or fuel if the operator complies with the placard instruction. (Requirement 1)\n- Timing pressure: the inspection and any rectification must be completed within a short window (15 hours time-in-service) after 15 April 1992, which concentrates labour and logistics demand into that interval. If the inspection identifies out-of-limits conditions, additional parts, skilled labour or grounding time may be required. (Requirement 2; Compliance 2)\n- Technical specification: the inspection and limits to be used are those set out in paragraphs 1–3 of the Instructions section of Mooney Service Bulletin M20-252 (dated 6 April 1992). The AD therefore delegates technical detail to the manufacturer’s service bulletin and makes compliance contingent on those procedures. (Requirement 2)\n- Temporary vs permanent effect: the placard and weight restriction are temporary — the placard must be removed after the inspection and any rectification. The AD therefore imposes a temporary operational constraint until the specified balancing check and any required fixes are done. (Requirement 1–2)\n- Reference to other authority: the AD notes a related FAA telegraphic AD as a reference point, indicating coordination or a common technical trigger for the measure. (Note)\n\nCompliance burden and implementation risk\n\n- Who pays: the aircraft owner/operator pays for fabricating and installing the placard, performing the inspection to the service bulletin standard, and paying for any rectification work (Requirement 1–2).\n- Compliance burden: requires access to the specified Mooney service bulletin, skilled personnel or maintenance facility to carry out the rudder static-balance inspection and any necessary adjustments, and time in service to complete the work within 15 hours after the specified date. (Requirement 2; Compliance 2)\n- Discretion: the AD prescribes specific actions and deadlines; it does not provide alternative compliance pathways in the text. The technical method is defined by the referenced manufacturer service bulletin, not by discretionary regulatory guidance in this AD. (Requirement 2)\n\nStated purpose vs concrete costs and incentives\n\n- Stated purpose: to prevent rudder imbalance and the resulting aerodynamic problems and possible loss of control, per the FAA information cited. (Background; Note)\n- Concrete costs and incentives: operators face short-term operational restrictions (reduced allowable gross weight while the placard is displayed), direct maintenance and labour costs for inspection and possible rectification, and scheduling constraints to meet the 15-hour inspection window. The manufacturer service bulletin sets the technical compliance standard and therefore shapes the required work and potential parts costs. (Requirement 1–2; Compliance 1–2)\n\nSource citations\n\nAll statements above are based on the text of AD/M20/47: Applicability; Requirement 1–2; Compliance 1–2; Note; Background."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific airworthiness issue (rudder static balance) in a limited fleet of aircraft. The scope remains precisely focused on the original safety concern identified by the FAA and adopted by CASA."},"complexity_factors":["Very short document — approximately 150 words","Only 2 substantive requirements with clear sequential steps","Single defined applicability (specific serial number ranges)","No nested exceptions or conditional logic","One external reference (FAA AD and Mooney Service Bulletin) but clearly identified","Simple compliance timeline: immediate + 15 hours time in service"],"plain_english_summary":"This is an **Airworthiness Directive** — essentially a mandatory safety fix issued by Australia's aviation safety regulator for specific aircraft.\n\n**What it does:**\nOrders owners of certain **Mooney M20J aeroplanes** (specific serial numbers listed) to take immediate safety action due to a **rudder balance problem**. An unbalanced rudder can cause dangerous aerodynamic issues and potentially lead to loss of control.\n\n**Who it affects:**\nOwners and operators of Mooney M20J aircraft with these specific serial numbers: 24-3201, 24-3218 through 24-3238, 24-3240 through 24-3250, and 24-3252 through 24-3256.\n\n**What must be done:**\n1. **Immediately** — Install a visible cockpit placard reducing the maximum weight limit to 1,243 kg (2,740 lb). This temporary restriction keeps the aircraft safe to fly while awaiting proper inspection.\n2. **Within 15 flight hours** — Have a mechanic inspect the rudder's static balance following specific manufacturer instructions (Mooney Service Bulletin M20-252). If repairs are needed, do them. Once fixed, remove the temporary weight-limit placard.\n\n**Why it matters:**\nThis is a **flight safety issue**. The US Federal Aviation Administration (FAA) identified that these aircraft could develop dangerous rudder imbalance. The directive prevents accidents by forcing immediate temporary restrictions followed by proper inspection and repair."}},"importantCases":[],"_links":{"self":"/api/acts/ad-m20-47-rudder-static-balance","history":"/api/acts/ad-m20-47-rudder-static-balance/history","analysis":"/api/acts/ad-m20-47-rudder-static-balance/analysis","conflicts":"/api/acts/ad-m20-47-rudder-static-balance/conflicts","importantCases":"/api/acts/ad-m20-47-rudder-static-balance/important-cases","documents":"/api/acts/ad-m20-47-rudder-static-balance/documents"}}