{"id":"F2006B07352","name":"AD/TB20/6 - Autopilot Pitch Servo Cable Guards","slug":"ad-tb20-6-autopilot-pitch-servo-cable-guards","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49452,"registerId":"commonwealth-F2006B07352-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TB20/6 - Autopilot Pitch Servo Cable Guards","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)  Aerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes\n\n \n\nAD/TB20/6  Autopilot Pitch Servo Cable Guards 2/86 DM Applicability:              All model TB20 with KAP 150/KFC 150 autopilot to STC SA 1785CE-D. Requirement:               King SB KS 177/178-3 Note: FAA AD 85-25-02 also refers.\n\nCompliance: Within 10 hours time in service after 16 January 1986.\n\n \n\nBackground: An installation problem has been identified which can result in jamming of primary pitch control. This condition has occurred in service.\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\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, time-bound safety directive from 1986 addressing a specific mechanical defect. It has not expanded beyond its original purpose of mandating a physical modification to prevent control jamming."},"complexity_factors":["Extremely short document (under 200 words)","Only 2 defined applicability criteria (aircraft model + specific autopilot STC)","Single requirement referencing external technical document (King Service Bulletin)","Simple compliance deadline (10 hours TIS after fixed date)","No nested conditions, exceptions, or cross-references to other legislation","Minimal regulatory machinery — essentially a safety notice with legal force"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety fix ordered by Australia's aviation regulator (CASA) for specific aircraft.\n\n**What it does:** Requires owners/operators of certain Socata TB20 Trinidad aeroplanes to install cable guards on their autopilot pitch servo systems. These guards prevent the autopilot cables from interfering with and jamming the primary pitch controls (the controls that make the plane go up or down).\n\n**Who it affects:** Anyone operating a Socata TB20 aircraft equipped with a KAP 150 or KFC 150 autopilot system installed under a specific supplemental type certificate (STC SA 1785CE-D). This is a particular aftermarket autopilot installation, not all TB20s.\n\n**Why it matters:** The background notes that this jamming has already happened \"in service\" — meaning it caused real problems in actual flight. A jammed pitch control is extremely dangerous; the pilot might lose the ability to control the aircraft's altitude. The directive gives a hard deadline: fix it within 10 flight hours after 16 January 1986.\n\n**Key reference:** The actual technical work is specified in \"King SB KS 177/178-3\" — a Service Bulletin from the autopilot manufacturer (King) that tells mechanics exactly what parts to install and how."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive, as published, imposes a corrective action on a defined subset of TB20 aeroplanes to address an identified installation problem that can jam primary pitch control. The text shows no indication that the scope has been expanded or narrowed from the original corrective intent; it specifies the affected installations (STC SA 1785CE-D), the required service bulletin (King SB KS 177/178-3), and a compliance deadline (10 hours TIS after 16 January 1986). (Applicability / Requirement / Compliance / Background)"},"complexity_factors":["Narrow and specific applicability (single model and specific autopilot installation) (Applicability)","Single, externally referenced corrective action (King SB KS 177/178-3) rather than multiple alternatives (Requirement)","Short and fixed compliance window creates operational pressure but simplifies scheduling choices (Compliance)","Safety-critical technical nature requires certified maintenance competence to implement (Background / Requirement)","Cross-reference to related FAA AD adds a layer of external regulatory linkage (Note)"],"plain_english_summary":"If you operate an Aerospatiale (Socata) TB20 with a KAP 150 or KFC 150 autopilot installed under STC SA 1785CE‑D, this directive mandates modifying the aircraft per King Service Bulletin KS 177/178‑3 within 10 hours TIS after 16 January 1986. It was issued to eliminate a reported risk of primary pitch‑control jamming and imposes prompt compliance costs and downtime on owners/operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb20-6-autopilot-pitch-servo-cable-guards","history":"/api/acts/ad-tb20-6-autopilot-pitch-servo-cable-guards/history","analysis":"/api/acts/ad-tb20-6-autopilot-pitch-servo-cable-guards/analysis","conflicts":"/api/acts/ad-tb20-6-autopilot-pitch-servo-cable-guards/conflicts","importantCases":"/api/acts/ad-tb20-6-autopilot-pitch-servo-cable-guards/important-cases","documents":"/api/acts/ad-tb20-6-autopilot-pitch-servo-cable-guards/documents"}}