{"id":"F2006B06151","name":"AD/PC-6/47 - Horizontal Stabiliser - Trim Warning System","slug":"ad-pc-6-47-horizontal-stabiliser-trim-warning-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46952,"registerId":"commonwealth-F2006B06151-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nPilatus Porter PC-6 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/PC-6/47 Horizontal Stabiliser - Trim ","sectionType":"part","heading":"AD/PC-6/47 Horizontal Stabiliser - Trim Warning System 5/2002","content":"# AD/PC-6/47 Horizontal Stabiliser \\- Trim Warning System 5/2002\n\nApplicability: Pilatus PC-6 Porter aeroplanes, all manufacturers serial numbers (MSN) up to and including MSN 939.\n\nRequirement: 1. Install a horizontal stabiliser trim, visual and audio warning, in accordance with Pilatus PC-6 Service Bulletin 180 Revision 1 dated 27 September 2001.\n\n2. Amend the Aircraft Flight Manual (AFM) by inserting AFM Supplement Report No. 02207 Rev 1 dated 25 March 2002.\n\nNote: Swiss FOCA AD 2002-134 refers.\n\nCompliance: Requirements 1 and 2 – Within 200 hours time in service after the effective date of this Directive, but no later than 31 December 2002, which ever occurs first.\n\nThis Airworthiness Directive becomes effective on 16 May 2002.\n\nBackground: The Swiss Federal Office for Civil Aviation (FOCA) has been advised of several instances of PC-6 aeroplanes taking off with the horizontal stabiliser incorrectly trimmed. When airborne this can result in higher than usual stick forces being required as airspeed increases. Unless prompt and proper pilot action is taken this condition could lead to loss of control, especially for aeroplanes with mechanical stabiliser trim.\n\nThis Directive requires installation of a trim warning system, which gives a visual and audio warning to the pilot when the aeroplane is on the ground and the trim is not in the safe-for-takeoff range.\n\n![Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 3 April 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 24 April 2002.","sortOrder":1}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD implements the corrective action described in the background (install a trim warning and update the AFM) for the defined aircraft population. It mirrors the safety concern reported to Swiss FOCA and does not expand or narrow the stated actions or affected serial-number range beyond those set out in this directive (see Background; Requirement; Applicability)."},"complexity_factors":["Narrow applicability: only Pilatus PC-6 Porter aeroplanes, serial numbers up to and including MSN 939 (Applicability).","Two discrete required actions: (1) install the trim warning per Pilatus PC-6 Service Bulletin 180 Rev 1; (2) insert AFM Supplement Report No. 02207 Rev 1 (Requirement 1–2).","Clear compliance window: within 200 hours time in service after the AD effective date, or by 31 December 2002, whichever is earlier (Compliance).","Dependence on external documents: mandatory work is defined by a manufacturer service bulletin and an AFM supplement (Requirement); the AD also references Swiss FOCA AD 2002-134 (Note).","Implementation needs parts and maintenance labour certified to perform the installation and AFM amendment (implied by installation per service bulletin and AFM change).","Legal basis and enforceability provided by CASA under CAR 1998 subregulation 39.1(1) (preamble), giving the AD regulatory force.","Absent cost, approval or equivalency guidance in the AD — operators must interpret compliance means from the service bulletin and AFM supplement (administrative/compliance uncertainty).","Effective date and notification logistics specified (effective 16 May 2002; Gazette notification 24 April 2002), which place a hard start on the compliance clock (Timing/administration)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Pilatus PC-6 Porter aeroplanes (MSN up to and including 939) to install a horizontal stabiliser trim visual-and-audio warning system and insert a specified AFM supplement. It aims to prevent takeoffs with unsafe stabiliser trim by giving pilots a ground warning; the work must be done to the manufacturer's service bulletin within the stated flight‑time or date limits."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific mechanical issue in a specific aircraft model. It has not expanded beyond its original purpose of mandating a trim warning system installation."},"complexity_factors":["Single, specific aircraft type and serial number range","Two straightforward requirements with clear cross-reference to manufacturer documents (Service Bulletin and AFM Supplement)","Simple compliance deadline (whichever comes first of two dates)","No nested conditions, exceptions, or defined terms section","Background provides clear safety rationale without legal cross-referencing"],"plain_english_summary":"This CASA safety order requires owners/operators of Pilatus PC‑6 Porter aircraft (serials up to 939) to fit a cockpit warning (lights and sound) that alerts pilots if the horizontal stabiliser trim is incorrectly set for takeoff, and to update the Aircraft Flight Manual. Compliance was required within 200 flight hours after 16 May 2002 or by 31 Dec 2002.\n\nIt was issued because several PC‑6s took off with trim mis-set, making controls heavier with speed and risking loss of control; the warning prevents that hazard."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-47-horizontal-stabiliser-trim-warning-system","history":"/api/acts/ad-pc-6-47-horizontal-stabiliser-trim-warning-system/history","analysis":"/api/acts/ad-pc-6-47-horizontal-stabiliser-trim-warning-system/analysis","conflicts":"/api/acts/ad-pc-6-47-horizontal-stabiliser-trim-warning-system/conflicts","importantCases":"/api/acts/ad-pc-6-47-horizontal-stabiliser-trim-warning-system/important-cases","documents":"/api/acts/ad-pc-6-47-horizontal-stabiliser-trim-warning-system/documents"}}