{"id":"F2005L02085","name":"AD/AT 800/6 - Horizontal Stabiliser Attachment Eyebolts","slug":"ad-at-800-6-horizontal-stabiliser-attachment-eyebolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":36300,"registerId":"commonwealth-F2005L02085-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Airtractor 800 Series Aeroplanes","sectionType":"division","heading":"Airtractor 800 Series Aeroplanes","content":"### Airtractor 800 Series Aeroplanes\n\n| AD/AT 800/6 | Horizontal Stabiliser Attachment Eyebolts | 9/2005 |\n| ----------- | ----------------------------------------- | ------ |\n\n| Applicability: | Model AT-802 and AT-802A aircraft, with serial numbers up to and including 802A-0188 that have any 7/16-inch eyebolt (part number AN47-30A) installed; aircraft with serial number 802A-0189 and subsequent; and all aircraft that have any 9/16-inch eyebolt (part number 30775-1) installed.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Tighten the four eyebolts that attach the front and rear spar of the horizontal stabiliser to the respective stabiliser strut using the torque values referenced in Snow Engineering Co. Service Letter (SL) No. 129, revised 21 October 2004.2. Replace eyebolts that attach the front and rear spar of the horizontal stabiliser to the respective stabiliser strut, in accordance with SL No. 129, Issued 26 September 1994, Revised 21 October 2004.3. For aircraft with serial numbers up to and including 802A-0188: As an alternative in order to use the increased replacement compliance times in Requirement 2 of this Directive, replace the steel brace assembly inside the stabiliser with a new steel brace assembly with larger bushings, and replace any 7/16-inch eyebolt with the 9/16-inch eyebolt part number 30775-1; in accordance with SL 129A, dated 7 August 2004.Do not install any 5/16-inch eyebolt (part number AN44-17A or AN44-21A), 7/16-inch eyebolt (AN47-22A or AN-47-30A), or 9/16-inch eyebolt (part number 30774-1 or 30775-1) that exceeds the corresponding cumulative hours time in service specified in Requirement 2 or 3 of this Directive.Note: FAA AD 2005-13-12 Amdt 39-14149 refers. |\n| Compliance:    | 1. Within 100 hours time in service or 12 calendar months after 1 September 2005, whichever occurs first, unless already accomplished. Tighten thereafter at intervals not to exceed 12 calendar months.2. Replace initially upon accumulating the applicable number of hours time in service specified in SL No. 129, revised 21 October 2004, or within 50 hours time in service after 1 September 2005, whichever occurs later. Replace thereafter at the intervals specified in SL No. 129, revised 21 October 2004.3. At any time after 1 September 2005. Use the applicable time in SL 129A, dated 7 August 2004. The repetitive replacement of Requirement 2 is still required.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |\n\n|             | This Airworthiness Directive becomes effective on 1 September 2005.                                                                                                                                                                                                                                                                                                                                                                              |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Background: | The FAA has received numerous reports of failures of horizontal stabiliser attachment eyebolts on AT-301, AT-400, and AT-602 aircraft. Engineering analysis concluded that the eyebolts failed as a result of high cycle, low-nominal stress; and most likely due to the loss of torque during service. Failure of an eyebolt could lead to an abrupt change or complete loss of pitch control and/or aircraft departure from controlled flight. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n20 July 2005","sortOrder":0},{"sectionNumber":"AD/AT 800/6","sectionType":"part","heading":"AD/AT 800/6","content":"## AD/AT 800/6","sortOrder":1},{"sectionNumber":"Horizontal Stabiliser Attachment Eyebolt","sectionType":"part","heading":"Horizontal Stabiliser Attachment Eyebolts","content":"## Horizontal Stabiliser Attachment Eyebolts","sortOrder":2},{"sectionNumber":"9/2005","sectionType":"part","heading":"9/2005","content":"## 9/2005","sortOrder":3}],"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":5,"scope_assessment":{"changed":false,"description":"The instrument sets applicability and actions for specified AT-802/AT-802A serials and eyebolt part numbers. The text does not indicate any amendment or expansion beyond the AD as published, so there is no evidentiary basis here to conclude the scope has changed from its original stated applicability."},"complexity_factors":["Applicability varies by model and specific serial-number ranges (Applicability).","Multiple part-number–specific instructions and prohibitions (Requirement).","Alternative compliance path requires fitting a new internal steel brace plus part upgrades for some early serials (Requirement).","Mixed time limits: calendar-based recurring torque intervals and hours-in-service replacement intervals, with initial and repetitive triggers (Compliance).","External references to manufacturer service letters and an FAA AD create cross-document dependencies (Requirement; Note)."],"plain_english_summary":"This directive requires operators of Airtractor AT-802 and AT-802A aircraft (specified serial numbers) to re-torque and regularly re-check four horizontal stabiliser eyebolts, replace eyebolts at specified hours-in-service or upgrade the stabiliser brace and eyebolts for certain early serials, and prohibits fitting certain eyebolt types beyond allowed service hours. It responds to reports of eyebolt fatigue and potential loss of pitch control; operators pay for inspections, torque and replacement work and must meet the AD’s time-in-service and calendar deadlines. (Requirement; Compliance; Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with focused scope on a specific safety-critical component. The original intent was to address eyebolt failures in Air Tractor aircraft, and the directive maintains that narrow focus on horizontal stabiliser attachment hardware. The alternative compliance path (Requirement 3) is an integral part of the safety solution rather than scope creep."},"complexity_factors":["Multiple applicability categories based on serial numbers and installed parts (three distinct groups)","Cross-references to external technical documents (Snow Engineering Service Letters SL No. 129 and SL 129A) without reproducing their full content","Nested compliance timelines with 'whichever occurs first/last' conditional logic","Alternative compliance path (Requirement 3) that modifies the standard replacement schedule but still requires ongoing repetitive replacement","Specific part number references (AN47-30A, 30775-1, etc.) that require technical familiarity","Dual measurement systems (flight hours vs calendar months) creating overlapping deadlines"],"plain_english_summary":"This AD requires owners/operators of Air Tractor AT-802/AT-802A aeroplanes (specific serial ranges and any using part no. 30775-1) to inspect, tighten, and replace the horizontal stabiliser eyebolts and associated fittings to prevent bolt failure from vibration. Failures can cause sudden loss of pitch control. It also bans installation of certain worn bolt part types and became effective 1 September 2005."}},"importantCases":[],"_links":{"self":"/api/acts/ad-at-800-6-horizontal-stabiliser-attachment-eyebolts","history":"/api/acts/ad-at-800-6-horizontal-stabiliser-attachment-eyebolts/history","analysis":"/api/acts/ad-at-800-6-horizontal-stabiliser-attachment-eyebolts/analysis","conflicts":"/api/acts/ad-at-800-6-horizontal-stabiliser-attachment-eyebolts/conflicts","importantCases":"/api/acts/ad-at-800-6-horizontal-stabiliser-attachment-eyebolts/important-cases","documents":"/api/acts/ad-at-800-6-horizontal-stabiliser-attachment-eyebolts/documents"}}