{"id":"F2006B04441","name":"AD/BELL 206/127 Amdt 1 - Main Rotor Hub Trunnion Master Spline","slug":"ad-bell-206-127-amdt-1-main-rotor-hub-trunnion-master-spline","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44278,"registerId":"commonwealth-F2006B04441-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 206/127 Amdt 1 - Main Rotor Hub Trunnion Master Spline","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 206/127\n\nAmdt 1\n\n  \nMain Rotor Hub Trunnion Master Spline 13/94\n\nDM\n\nApplicability: Models 206A; 206B and B-1; and 206L, L-1, L-3 and L-4 fitted with main rotor hub trunnion P/n 206-011-113-103 or P/n 206-011-120-103.\n\nRequirement: Action in accordance with Bell, Alert S.B. 206-93-75, or Alert S.B. 206L-93-90 Rev.\n\nA as applicable.\n\nNote: FAA AD 94-20-03 refers, this supersedes FAA Priority Letter AD 93-22-11.\n\nCompliance: Unless already accomplished, within 50 hours time in service, or 90 days after\n\n19 October 1994, whichever occurs first. The effective date for the initial issue was 15 December 1993.\n\nBackground: The manufacturer has advised that some trunnions may have been manufactured with the master spline located incorrectly. This will result in the pitch change links being mis-aligned.\n\nAmendment 1 requires additional work for 206L models, in that the spline location in Figure 3 of the original Requirement Document was incorrect.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 does not broaden the list of affected aircraft or add part numbers; it corrects an incorrect spline location shown in Figure 3 of the original requirement document and requires additional corrective work specifically for 206L models. In practical terms the scope was narrowly altered to change the required technical action for those variants rather than expand applicability."},"complexity_factors":["Narrow applicability: specific Bell 206 submodels and two exact trunnion part numbers","Relies on external documents (Bell Alert Service Bulletins) for procedural detail","Short compliance window (50 flight hours or 90 days) creates scheduling pressure for operators","Amendment corrects a figure and adds tasks for 206L models, requiring reassessment of prior compliance","Requires certified maintenance action (inspection/realignment/repair) of a safety‑critical rotor component","Cross-references FAA ADs which may affect international operators and record-keeping"],"plain_english_summary":"This airworthiness directive requires operators and maintenance organisations of specified Bell 206 series helicopters fitted with trunnion P/n 206-011-113-103 or P/n 206-011-120-103 to inspect and, if necessary, correct the main rotor hub trunnion master spline in accordance with the applicable Bell Alert Service Bulletin. It addresses mislocated splines that can misalign pitch change links and was to be complied with within 50 flight hours or 90 days of 19 October 1994; Amendment 1 corrects a figure and adds work for 206L models."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD remains tightly focused on its original purpose: correcting a specific manufacturing defect in main rotor hub trunnions. Amendment 1 did not expand scope — it merely corrected an error in the technical instructions for one model variant (206L series). The applicability, core requirement, and safety objective remain unchanged from the initial issue."},"complexity_factors":["Single, specific mechanical defect with narrow applicability (2 part numbers, specific model series)","Clear compliance pathway: reference to existing manufacturer service bulletins (Alert S.B. 206-93-75 and 206L-93-90 Rev. A)","Simple conditional deadline: 'whichever occurs first' logic","Minimal cross-referencing: one FAA AD reference for background context only","Short document (approximately 200 words), no interpretation section with defined terms","One amendment addressing a specific technical correction (Figure 3 error for 206L models)"],"plain_english_summary":"This AD orders mandatory inspection and repair of Bell 206/Agusta-Bell 206 helicopters with specific hub part numbers to correct a manufacturing defect in the main rotor hub trunnion that can misposition the master spline and misalign pitch change links, risking rotor control. It affects owners, operators and maintainers of those models and requires compliance within 50 flight hours or 90 days after 19 Oct 1994. Amendment 1 adds extra work for 206L models due to a wrong diagram."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-127-amdt-1-main-rotor-hub-trunnion-master-spline","history":"/api/acts/ad-bell-206-127-amdt-1-main-rotor-hub-trunnion-master-spline/history","analysis":"/api/acts/ad-bell-206-127-amdt-1-main-rotor-hub-trunnion-master-spline/analysis","conflicts":"/api/acts/ad-bell-206-127-amdt-1-main-rotor-hub-trunnion-master-spline/conflicts","importantCases":"/api/acts/ad-bell-206-127-amdt-1-main-rotor-hub-trunnion-master-spline/important-cases","documents":"/api/acts/ad-bell-206-127-amdt-1-main-rotor-hub-trunnion-master-spline/documents"}}