{"id":"F2007L01561","name":"AD/AT 600/7 - Horizontal Stabiliser Brace Tube Assembly","slug":"ad-at-600-7-horizontal-stabiliser-brace-tube-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":66062,"registerId":"commonwealth-F2007L01561-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Airtractor 600 Series Aeroplanes","sectionType":"division","heading":"Airtractor 600 Series Aeroplanes","content":"### Airtractor 600 Series Aeroplanes\n\n| AD/AT 600/7 | Horizontal Stabiliser Brace Tube Assembly | 7/2007 |\n| ----------- | ----------------------------------------- | ------ |\n\n| Applicability: | Model AT-602 aircraft, with serial numbers up to and including 602-0695, fitted with a part number 30012-7 horizontal stabiliser brace tube assembly.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. In accordance with Snow Engineering Co. Service Letter No. 235, dated25 August 2004, revised 24 October 2006, or later FAA approved revision, accomplish the following:a. Install access holes for visual inspection of the part number 30012-7 horizontal stabiliser brace tube assembly (tube assembly).b. Conduct a detailed visual inspection for cracks in the part number 30012-7 tube assembly.2. Replace the part number 30012-7 tube assembly with a new design part number 30766-1 tube assembly in accordance with Snow Engineering Co. Service Letter No. 129A, dated 7 August 2004, revised 15 November 2005; Service LetterNo. 235, dated 25 August 2004, revised 24 October 2006; and Drill Template -602, Drawing No. SL129-602, dated 2 August 2004.3. A part number 30012-7 tube assembly shall not be installed on any aircraft.Note 1: Replacement of the part number 30012-7 tube assembly with a new design part number 30766-1 tube assembly is terminating action for the repetitive inspection requirement of this Directive.Note 2: FAA AD 2007-10-01 Amdt 39-15042 refers. |\n| Compliance:    | 1. Upon accumulating 2,000 hours time in service or within 60 days after 5 July 2007, whichever occurs later. Inspect thereafter at intervals not to exceed 100 hours time in service; until a part number 30766-1 tube assembly is installed.2. Before further flight after any Requirement 1 inspection where cracks are found.3. As of 5 July 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n|                | This Airworthiness Directive becomes effective on 5 July 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n\n| Background: | The FAA received two reports of Model AT-602 aircraft with cracked horizontal stabiliser brace tube assemblies. Undetected cracks could result in failure of the horizontal stabiliser, and could affect the ability to control pitch with consequent loss of control. |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n16 May 2007","sortOrder":0},{"sectionNumber":"AD/AT 600/7","sectionType":"part","heading":"AD/AT 600/7","content":"## AD/AT 600/7","sortOrder":1},{"sectionNumber":"Horizontal Stabiliser Brace Tube Assembl","sectionType":"part","heading":"Horizontal Stabiliser Brace Tube Assembly","content":"## Horizontal Stabiliser Brace Tube Assembly","sortOrder":2},{"sectionNumber":"7/2007","sectionType":"part","heading":"7/2007","content":"## 7/2007","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":4,"scope_assessment":{"changed":false,"description":"The directive's scope aligns with its stated safety trigger: addressing cracked horizontal stabiliser brace tube assemblies on a defined subset of AT‑602 aircraft. It prescribes inspection, modification (access holes), and mandatory replacement with a specified new part, plus a prohibition on reinstalling the old part. The instrument does not expand beyond that technical remedy and therefore does not appear to change scope from its stated purpose in the document."},"complexity_factors":["Narrow applicability but precise serial-number cutoff (Applicability): limits affected fleet to AT‑602 aircraft with serials up to 602‑0695 — simplifies target population but requires accurate records.","Dual procedural requirements (Requirement 1): installing access holes and performing detailed visual inspections increases workmanship steps and may need minor structural work.","Mandatory replacement with specific new part and referenced technical documents (Requirement 2): replacement must follow Snow Engineering Service Letters No. 129A and 235 and Drill Template SL129‑602, creating dependency on external documents and parts procurement.","Termination and prohibition mechanics (Note 1 and Requirement 3): installing part 30766‑1 is terminating action for repetitive inspections and part 30012‑7 is thereafter forbidden, creating a clear compliance end-state but requiring verification of part numbers.","Compliance timing rules (Compliance 1–3): initial inspection at 2,000 hours TIS or within 60 days after 5 July 2007, recurring every 100 hours until replacement, and immediate grounding if cracks found — enforces frequent checks and potential aircraft downtime.","Reference to FAA approval and AD (Requirement 1 and Note 2): use of 'later FAA approved revision' and cross-reference to FAA AD 2007‑10‑01 ties acceptance to external regulator approvals and updates.","Operational cost and logistics: access hole installation, inspections, and mandatory replacement imply direct costs to owners/operators (parts, labour, downtime) and possible supply-chain timing risks.","Inspection standard ambiguity: 'detailed visual inspection' relies on operator/maintainer judgment and may require repeated inspections or specialist skills to detect cracks reliably."],"plain_english_summary":"This directive requires owners/operators of Airtractor AT‑602 aircraft (serial numbers up to and including 602‑0695) fitted with part 30012‑7 horizontal stabiliser brace tubes to add access holes, carry out repeated visual inspections for cracks, and replace the 30012‑7 with redesigned part 30766‑1. Inspections continue at short intervals until replacement; fitting the new part stops the repeating inspections. The measure aims to address reports of cracked tubes that could lead to loss of pitch control."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted airworthiness directive addressing a specific safety defect in a specific aircraft component. The scope remains tightly focused on the horizontal stabiliser brace tube assembly issue as originally identified."},"complexity_factors":["Multiple cross-referenced external documents (Snow Engineering Service Letters No. 235 and 129A, Drill Template Drawing)","Conditional compliance deadlines ('whichever occurs later', 'before further flight')","Specific part number tracking required (30012-7 vs 30766-1)","Nested requirements: inspection required until terminating action (replacement) is completed","Serial number applicability cutoff (602-0695) creates boundary condition issues"],"plain_english_summary":"This AD mandates owners/operators of Air Tractor AT-602s (serials up to 602‑0695) fitted with the older horizontal stabiliser brace tube (P/N 30012‑7) to drill access holes, perform an initial and recurring visual inspection for cracks, and replace the part with the improved P/N 30766‑1. It follows reports of cracking that could cause loss of pitch control; the old tube is prohibited from installation from 5 July 2007."}},"importantCases":[],"_links":{"self":"/api/acts/ad-at-600-7-horizontal-stabiliser-brace-tube-assembly","history":"/api/acts/ad-at-600-7-horizontal-stabiliser-brace-tube-assembly/history","analysis":"/api/acts/ad-at-600-7-horizontal-stabiliser-brace-tube-assembly/analysis","conflicts":"/api/acts/ad-at-600-7-horizontal-stabiliser-brace-tube-assembly/conflicts","importantCases":"/api/acts/ad-at-600-7-horizontal-stabiliser-brace-tube-assembly/important-cases","documents":"/api/acts/ad-at-600-7-horizontal-stabiliser-brace-tube-assembly/documents"}}