{"id":"F2007L01253","name":"AD/BELL 407/29 - Horizontal Stabiliser Skin at the Tailboom Attachment Inserts","slug":"ad-bell-407-29-horizontal-stabiliser-skin-at-the-tailboom-attachment-inserts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":65391,"registerId":"commonwealth-F2007L01253-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bell Helicopter Textron Canada (BHTC) 40","sectionType":"division","heading":"Bell Helicopter Textron Canada (BHTC) 407 Series Helicopters","content":"### Bell Helicopter Textron Canada (BHTC) 407 Series Helicopters\n\n| AD/BELL 407/29 | Horizontal Stabiliser Skin at theTailboom Attachment Inserts | 7/2007 DM |\n| -------------- | ------------------------------------------------------------ | --------- |\n\n| Applicability: | Model 407 helicopters.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Verify the serial number of the horizontal stabiliser in accordance with Part I of BHTC Alert Service Bulletin (ASB) 407-06-72 original issue, or later Transport Canada approved revision.If the horizontal stabiliser installed on the helicopter has a serial number listed below, accomplish Requirement 2.Affected Serial Numbers:BP725, -750, -751, -752, -753, -756, -758, -760, -765, -769, -770, -771, -775,-776, -778, -779, -780, -781, -785, -787, -788, -789, -790, -795, -796, -797, -800, -801, -802, -803, -805, -829.2. Inspect the affected parts in accordance with Part II of ASB 407-06-72 original issue, or later Transport Canada approved revision.If damaged parts are detected during any inspection, replace the parts before further flight. If parts are not damaged, repeat the inspection.3. Replace the affected horizontal stabiliser in accordance with Part III of ASB407-06-72 original issue, or later Transport Canada approved revision.Note: Transport Canada AD CF-2007-03 refers. |\n| Compliance:    | 1. Within 100 hours time in service after 8 May 2007, but no later than 8 June 2007; unless already accomplished.2. Initially at the time of Requirement 1 compliance, if affected. Repetitively inspect thereafter at intervals not to exceed 600 flight hours or the annual inspection, whichever occurs first; until accomplishment of Requirement 3.3. No later than 30 September 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n|                | This Airworthiness Directive becomes effective on 8 May 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n\n| Background: | Horizontal stabilisers part number 407-023-801-109 may have manufacturing flaws on the inside surface of the upper and/or lower skin at the tailboom attachment inserts. These flaws may result in cracking of the skin and failure of the horizontal stabiliser. |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n2 May 2007","sortOrder":0},{"sectionNumber":"AD/BELL 407/29","sectionType":"part","heading":"AD/BELL 407/29","content":"## AD/BELL 407/29","sortOrder":1},{"sectionNumber":"Horizontal Stabiliser Skin at theTailboo","sectionType":"part","heading":"Horizontal Stabiliser Skin at theTailboom Attachment Inserts","content":"## Horizontal Stabiliser Skin at the  \nTailboom Attachment Inserts","sortOrder":2},{"sectionNumber":"7/2007 DM","sectionType":"part","heading":"7/2007 DM","content":"## 7/2007 DM","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":"Scope is limited to Model 407 helicopters fitted with the listed horizontal stabiliser serial numbers and prescribes inspection and replacement actions to address identified manufacturing flaws (Applicability; Requirement; Compliance). The Directive does not broaden applicability beyond those specified units but imposes time-bound and recurring maintenance obligations on affected operators."},"complexity_factors":["Serial-number–specific applicability requiring identification of individual stabiliser units (Requirement 1).","Three-step procedural structure: verify serial number, inspect affected parts, and replace the horizontal stabiliser (Requirements 1–3).","Reference to manufacturer Alert Service Bulletin (ASB 407-06-72) Parts I–III and to later Transport Canada–approved revisions, creating cross-regulatory document dependence (Requirement).","Multiple mandatory time constraints and deadlines: initial check within 100 hours or by 8 June 2007, repetitive inspections at ≤600 flight hours or annual, and final replacement by 30 September 2008 (Compliance).","Immediate grounding risk for damaged parts (must be replaced before further flight) which raises operational disruption and potential logistical demand for replacement parts (Requirement 2).","Enforcement and signature by the Civil Aviation Safety Authority delegate, creating regulatory compliance obligations for operators (document footer).","Cross-reference to Transport Canada AD CF-2007-03 and reliance on the manufacturer's ASB increases coordination and record-keeping complexity (Note/Requirement)."],"plain_english_summary":"This Directive requires Bell 407 operators to check horizontal stabiliser serial numbers, inspect any listed units for internal skin flaws, and replace affected stabilisers by set deadlines; inspections repeat until replacement or damage requires immediate replacement (Requirements 1–3; Compliance). Operators pay inspection and replacement costs; the Civil Aviation Safety Authority enforces compliance. Mechanically, it shifts maintenance schedules and imposes recurring inspection burdens (600‑hour/annual intervals) and a final replacement deadline to mitigate risk of skin cracking and stabiliser failure."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive addressing a specific manufacturing defect in a specific aircraft part. The scope remains precisely limited to the identified safety issue without expansion into broader operational or regulatory matters."},"complexity_factors":["Single, specific mechanical issue with clear part numbers and serial numbers","Three distinct requirements with clear sequential logic (identify → inspect → replace)","Simple compliance timeline with specific dates and flight hour thresholds","Only 33 specific serial numbers to check against","References to external technical document (Alert Service Bulletin) but provides sufficient standalone detail","No nested exceptions or conditional logic beyond 'if affected, then inspect'"],"plain_english_summary":"This AD orders operators of Bell 407 helicopters to inspect and ultimately replace certain horizontal stabilisers after hidden manufacturing flaws were found that can cause cracking and in‑flight separation. Affected stabilisers are identified by serial number; if your stabiliser is on the list you must inspect, remove damaged parts before flight, carry out recurring checks, and fit a serviceable stabiliser within the mandated compliance window. CASA enforces the requirement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-407-29-horizontal-stabiliser-skin-at-the-tailboom-attachment-inserts","history":"/api/acts/ad-bell-407-29-horizontal-stabiliser-skin-at-the-tailboom-attachment-inserts/history","analysis":"/api/acts/ad-bell-407-29-horizontal-stabiliser-skin-at-the-tailboom-attachment-inserts/analysis","conflicts":"/api/acts/ad-bell-407-29-horizontal-stabiliser-skin-at-the-tailboom-attachment-inserts/conflicts","importantCases":"/api/acts/ad-bell-407-29-horizontal-stabiliser-skin-at-the-tailboom-attachment-inserts/important-cases","documents":"/api/acts/ad-bell-407-29-horizontal-stabiliser-skin-at-the-tailboom-attachment-inserts/documents"}}