{"id":"F2006B04450","name":"AD/BELL 206/136 - Hydraulic Servo Actuator Shoulder Bolt","slug":"ad-bell-206-136-hydraulic-servo-actuator-shoulder-bolt","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44287,"registerId":"commonwealth-F2006B04450-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 206/136 - Hydraulic Servo Actuator Shoulder Bolt","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 206/136 Hydraulic Servo Actuator Shoulder Bolt 12/95\n\nApplicability: Bell Model 206A and 206B helicopters fitted with servos which have been overhauled or repaired by a facility not approved by HR Textron.\n\nRequirement: Unless previously carried out action in accordance with Bell ASB 206-95-84.\n\nNote 1. Transport Canada AD CF-95-11 refers.\n\nNote 2. The shoulder bolts called up in the Requirement Document were manufactured without undercut by HR Textron until February 1975. For this reason the absence of undercut should not result in rejection if other inspection criteria are met.\n\nCompliance: Within 50 hours time in service from 15 November 1995 or by 31 December 1995, whichever occurs first.\n\nBackground: Bell Textron has advised that unauthorised rework/repair of the shoulder bolts may have been carried out. An inspection of the shoulder bolts for possible hydrogen embrittlement is also required.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument, as drafted, limits scope to specific Bell 206 variants and to servos overhauled/repaired by non-approved facilities and prescribes a short compliance window and inspection action. The text contains no indication that the scope has been broadened or narrowed from its stated applicability; therefore there is no evidence here of a scope change from the directive's expressed intent."},"complexity_factors":["Targeted applicability limited to Bell Model 206A and 206B with servos overhauled/repaired by a facility not approved by HR Textron (Applicability).","Mandated compliance window: within 50 hours time in service from 15 November 1995 or by 31 December 1995, whichever occurs first (Compliance).","Requirement ties compliance to prior action in Bell ASB 206-95-84; operators must check whether that action has already been done (Requirement).","Technical inspection for possible hydrogen embrittlement and potential corrective action implies specialised inspection capability and possible part replacement (Background & Requirement).","Note permitting absence of undercut on shoulder bolts manufactured before February 1975 to be acceptable if other inspection criteria are met introduces conditional acceptance criteria (Note 2).","Cross-reference to Transport Canada AD CF-95-11 creates dependency on an external airworthiness directive (Note 1).","Compliance imposes an information burden on operators to determine whether servos were repaired/overhauled by non‑approved facilities and therefore whether the AD applies (Applicability, Background).","Issued under the Civil Aviation Safety Authority Part 39 schedule of airworthiness directives, so enforcement and record-keeping fall to CASA and affected operators (header)."],"plain_english_summary":"Requires inspection and, if necessary, corrective action on hydraulic servo actuator shoulder bolts for Bell Model 206A and 206B helicopters when servos were overhauled or repaired by a facility not approved by HR Textron. Operators must follow Bell ASB 206‑95‑84 within 50 hours time-in-service from 15 November 1995 or by 31 December 1995, whichever is earlier. The directive responds to possible unauthorised rework and the risk of hydrogen embrittlement in those bolts."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in specific aircraft. It has not expanded beyond its original purpose of addressing potentially defective shoulder bolts in Bell 206 helicopters with questionable repair histories."},"complexity_factors":["Single, specific mechanical component addressed (shoulder bolts in hydraulic servo actuators)","Narrow applicability: only two helicopter models (206A and 206B) with specific repair history","Single compliance requirement referencing an external technical document (Bell ASB 206-95-84)","Simple time-based compliance deadline (50 hours or fixed date)","Only one defined condition (servos overhauled by non-HR Textron approved facility)","Minimal cross-referencing (one Canadian AD mentioned in note only)","No nested exceptions or conditional logic chains"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of Bell 206A and 206B helicopters whose hydraulic servos were overhauled or repaired by non‑approved facilities to inspect—and if necessary replace—shoulder bolts in the hydraulic servo actuators per Bell Alert Service Bulletin 206‑95‑84. It addresses hydrogen embrittlement that can cause sudden bolt failure and loss of hydraulic control; inspections must be done within the specified compliance window (50 flight hours after 15 Nov 1995 or by 31 Dec 1995)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-136-hydraulic-servo-actuator-shoulder-bolt","history":"/api/acts/ad-bell-206-136-hydraulic-servo-actuator-shoulder-bolt/history","analysis":"/api/acts/ad-bell-206-136-hydraulic-servo-actuator-shoulder-bolt/analysis","conflicts":"/api/acts/ad-bell-206-136-hydraulic-servo-actuator-shoulder-bolt/conflicts","importantCases":"/api/acts/ad-bell-206-136-hydraulic-servo-actuator-shoulder-bolt/important-cases","documents":"/api/acts/ad-bell-206-136-hydraulic-servo-actuator-shoulder-bolt/documents"}}