{"id":"F2006B04446","name":"AD/BELL 206/131 - Vertical Fin - External Doubler","slug":"ad-bell-206-131-vertical-fin-external-doubler","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44283,"registerId":"commonwealth-F2006B04446-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 206/131 - Vertical Fin - External Doubler","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters\n\nAD/BELL 206/131 Vertical Fin \\- External Doubler 5/95\n\nApplicability: Bell Model 206A and 206B Helicopters Serial Numbers 4 to 1163 inclusive, with an external doubler (P/N 206-020-113-109) on the left hand side of the vertical fin assembly adjacent to the support forgings.\n\nRequirement: 1. Remove the vertical fin and dye penetrant inspect the inboard and outboard surfaces of the fin attachment forgings. Inspect in accordance with Bell Alert Service Bulletin ASB 206-91-60 Part 1.\n\n2. Prior to re-installing the fin assembly, visually inspect for gaps between the tailboom and the fin mounting inserts. Eliminate all gaps in accordance with Bell Alert Service Bulletin ASB 206-91-60 Part II.\n\nNote: FAA AD 92-09-07 refers.\n\nCompliance: Action in accordance with Requirements 1 and 2 before 27 May 1995 or within 100 hours time in service from 27 April 1995, whichever occurs first.\n\nBackground: The manufacturer has reported that the installation of the external doubler on the fin may require spacers between the fin and tailboom to preclude unacceptable loads on the fin support forgings.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with no indication of scope creep. It addresses a specific manufacturing defect in specific aircraft and does not appear to have expanded beyond its original technical safety purpose."},"complexity_factors":["Single, specific technical requirement with only 2 action items","Limited applicability (specific serial number range and part number)","No defined terms section — uses standard aviation terminology","No cross-references to other legislation (only references manufacturer service bulletins and FAA AD for context)","Clear, unconditional compliance requirement with fixed deadline","Short document (approximately 200 words)"],"plain_english_summary":"This AD required owners/operators of Bell 206A/206B helicopters (S/N 4–1163) with an external left-side vertical-fin doubler to remove the fin, perform dye‑penetrant inspections of the fin attachment forgings, and correct any gaps at the tailboom/fin mounts with spacers. It addressed improper loads from the doubler that could crack or cause loss of the fin in flight. The mandated work was retrospective, due by 27 May 1995 or within 100 flight hours after 27 Apr 1995."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope is limited to Bell 206A/206B helicopters with the specified external doubler and serial numbers 4–1163; the directive prescribes inspection and corrective action for those installations only and does not expand to other models, parts, or serial ranges."},"complexity_factors":["Targeted applicability: specific airframe models, serial number range (4–1163) and a single external doubler part number (P/N 206-020-113-109) narrow the population but require verification of fittings.","Mandatory removal and dye‑penetrant inspection of attachment forgings requires specialist inspection skills and access to the fin assembly.","Repair action (eliminating gaps; installing/removing spacers) may need parts, fitting work and engineering judgement to restore correct load paths.","Normative dependence on manufacturer's Alert Service Bulletin ASB 206-91-60 Parts I & II creates procedural dependencies and possible interpretation issues.","Short compliance window (by 27 May 1995 or within 100 hours from 27 April 1995) may concentrate workload and logistics for operators.","Cross-reference to FAA AD 92-09-07 implies international coordination and potential additional compliance considerations."],"plain_english_summary":"This airworthiness directive requires operators of Bell Model 206A and 206B helicopters (serial numbers 4–1163) fitted with a specific external doubler (P/N 206-020-113-109) to remove the vertical fin, carry out dye‑penetrant inspections of the fin attachment forgings, and, before reinstallation, visually check and eliminate any gaps between the tailboom and fin mounting inserts in accordance with Bell Alert Service Bulletin ASB 206-91-60 Parts I & II. Compliance is required by 27 May 1995 or within 100 hours from 27 April 1995. The directive responds to a manufacturer report that the doubler can change load paths and spacers may be needed to prevent unacceptable loads on the fin support forgings."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-131-vertical-fin-external-doubler","history":"/api/acts/ad-bell-206-131-vertical-fin-external-doubler/history","analysis":"/api/acts/ad-bell-206-131-vertical-fin-external-doubler/analysis","conflicts":"/api/acts/ad-bell-206-131-vertical-fin-external-doubler/conflicts","importantCases":"/api/acts/ad-bell-206-131-vertical-fin-external-doubler/important-cases","documents":"/api/acts/ad-bell-206-131-vertical-fin-external-doubler/documents"}}