{"id":"F2006B06123","name":"AD/PC-6/20 - Trim Cable Guide Tubes - Inspection","slug":"ad-pc-6-20-trim-cable-guide-tubes-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46891,"registerId":"commonwealth-F2006B06123-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PC-6/20 - Trim Cable Guide Tubes - 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)  Pilatus Porter PC-6 Series Aeroplanes\n\n \n\nAD/PC-6/20 Trim Cable Guide Tubes - Inspection 11/67\n\nApplicability: All models not modified in accordance with Pilatus SB No. 72. Document:  Pilatus SB No. 72.\n\nCompliance: At intervals not exceeding 50 hours time in service after 2 November 1967.\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\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text presents a single, initial airworthiness directive establishing inspection intervals or an alternative modification path. Nothing in the supplied text indicates a change of scope from an earlier or different requirement; the directive itself limits scope to unmodified PC-6 models and prescribes inspections or modification per Pilatus SB No. 72 (Applicability; Document; Compliance)."},"complexity_factors":["Narrow technical scope limited to trim cable guide tubes","Clear recurring compliance interval (50 hours TIS) reduces interpretive ambiguity","Dependence on an external technical document (Pilatus SB No. 72) for procedures and acceptance criteria","Applicability exception (aircraft modified per SB No. 72) requires operators to track modification status","Administrative tracking burden (time-in-service logging) for recurrent inspections"],"plain_english_summary":"What this instrument requires\n\n- This is an airworthiness directive issued under the Civil Aviation Safety Authority (header: \"Civil Aviation Safety Authority\" and \"Schedule of Airworthiness Directives\"). It applies to Pilatus Porter PC-6 series aeroplanes and is titled \"AD/PC-6/20 Trim Cable Guide Tubes - Inspection\" (title and header).\n\nWho is affected\n\n- The directive applies to all Pilatus PC-6 models that have not been modified according to Pilatus Service Bulletin No. 72 (\"Applicability: All models not modified in accordance with Pilatus SB No. 72\") (Applicability).\n\nWhat must be done and when\n\n- Operators/owners must inspect the trim cable guide tubes at intervals not exceeding 50 hours time in service, beginning from 2 November 1967 (\"Compliance: At intervals not exceeding 50 hours time in service after 2 November 1967\") (Compliance).\n\nHow to perform the work\n\n- The directive refers to Pilatus SB No. 72 as the relevant document for the modification/inspection instructions (\"Document: Pilatus SB No. 72\") (Document). The Service Bulletin is the technical reference for the required inspection procedure or the modification that removes the directive's applicability.\n\nWho decides and who pays\n\n- The Civil Aviation Safety Authority issued the directive (header). The economic and operational burden falls on the aircraft owners/operators: they must carry out the inspections at the stated interval or have the modification installed per Pilatus SB No. 72 to avoid the inspection requirement (Applicability; Compliance; Document). Any costs for inspections, repairs or modifications are the responsibility of owners/operators, because the directive requires them to take the action.\n\nPractical mechanics, incentives and trade-offs (source-grounded)\n\n- The directive forces a recurring inspection obligation (50-hour inspection cycle) for aircraft that remain unmodified. This creates ongoing direct costs (inspection labour and any repairs) and recurring aircraft downtime while inspections are performed (Compliance). Installing the Pilatus SB No. 72 modification removes an aircraft from the pool required to do these inspections (Applicability; Document), which creates an incentive to modify if the one-off modification cost is lower than the ongoing inspection-and-repair costs.\n\n- The directive is narrowly targeted: it identifies a particular part (trim cable guide tubes) and a single corrective path (inspection at a set interval or modification per the Service Bulletin). The Service Bulletin contains the technical method and therefore delegates technical detail to the manufacturer document rather than restating it in the directive (Document).\n\nImplementation risks and compliance burden\n\n- The directive sets a clear recurrent interval but does not itself include the step-by-step inspection procedure in the text provided here; the procedure is in Pilatus SB No. 72 (Document). That delegation means compliance requires access to and reliance on the Service Bulletin for the exact inspection steps, acceptance criteria, and any repair instructions.\n\n- The directive contains a date reference (from 2 November 1967) that establishes when the recurring intervals start (Compliance). Operators must track time in service to meet the 50-hour threshold.\n\nSource citations used in this summary: header identifying the Civil Aviation Safety Authority and schedule of Airworthiness Directives (header), \"Applicability: All models not modified in accordance with Pilatus SB No. 72\" (Applicability), \"Document: Pilatus SB No. 72\" (Document), and \"Compliance: At intervals not exceeding 50 hours time in service after 2 November 1967\" (Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a historical airworthiness directive from 1967 (reference number 11/67) addressing a specific mechanical inspection requirement for a single aircraft type. It has not expanded beyond its original narrow scope of ensuring trim cable guide tube integrity in unmodified Pilatus PC-6 aircraft."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 2 defined references (Pilatus SB No. 72, time in service)","No cross-references to other legislation or regulations beyond the enabling authority (Civil Aviation Regulations 1998, Part 39)","Simple conditional logic: applies to all models EXCEPT those already modified per SB No. 72","Single compliance requirement with clear time trigger (50 hours TIS after specified date)","No nested exceptions or sub-conditions"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of **Pilatus Porter PC-6 series aircraft** to inspect the **trim cable guide tubes** (parts that help control the aircraft's pitch trim system) at regular intervals.\n\n**Who it affects:** Anyone operating a Pilatus PC-6 aircraft that has **not** been modified according to Pilatus Service Bulletin No. 72.\n\n**What must be done:**\n- **Inspection required:** Check the trim cable guide tubes\n- **How often:** Every 50 hours of flight time (\"time in service\")\n- **Starting when:** After 2 November 1967\n\n**Why it matters:** Trim cable guide tubes are critical to flight safety. If they fail, the pilot may lose control of the aircraft's pitch trim, making the plane difficult or dangerous to fly. This AD ensures potential wear or damage is caught before it causes an accident.\n\n**Key point:** This is a recurring inspection, not a one-off fix. Operators must keep doing it every 50 flight hours until the aircraft is modified per the manufacturer's Service Bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-20-trim-cable-guide-tubes-inspection","history":"/api/acts/ad-pc-6-20-trim-cable-guide-tubes-inspection/history","analysis":"/api/acts/ad-pc-6-20-trim-cable-guide-tubes-inspection/analysis","conflicts":"/api/acts/ad-pc-6-20-trim-cable-guide-tubes-inspection/conflicts","importantCases":"/api/acts/ad-pc-6-20-trim-cable-guide-tubes-inspection/important-cases","documents":"/api/acts/ad-pc-6-20-trim-cable-guide-tubes-inspection/documents"}}