{"id":"F2007L02675","name":"AD/BO 105/23 - Main Rotor Blade Secondary Bolt Locking","slug":"ad-bo-105-23-main-rotor-blade-secondary-bolt-locking","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":68547,"registerId":"commonwealth-F2007L02675-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter BO 105 Series Helicopters","sectionType":"division","heading":"Eurocopter BO 105 Series Helicopters","content":"### Eurocopter BO 105 Series Helicopters\n\n| AD/BO 105/23 | Main Rotor Blade Secondary Bolt Locking | 10/2007 |\n| ------------ | --------------------------------------- | ------- |\n\n| Applicability: | All Messerschmitt-Bolkow Blohm (MBB) Model BO 105 helicopters.                                                                                                                                           |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the requirements of Transport Canada AD CF-88-18.Note: MBB ASB-BO-105-10-101 Revision 3 refers.                                                                                |\n| Compliance:    | Unless already accomplished, before 27 October 2007.                                                                                                                                                     |\n|                | This Airworthiness Directive becomes effective on 27 September 2007.                                                                                                                                     |\n| Background:    | German LBA AD 87-106/2 mandated the use of lockwire as an anti-rotational lock for the secondary bolt of the main rotor blade. MBB later devised a lockwasher as a more suitable anti-rotational device. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n13 August 2007","sortOrder":0},{"sectionNumber":"AD/BO 105/23","sectionType":"part","heading":"AD/BO 105/23","content":"## AD/BO 105/23","sortOrder":1},{"sectionNumber":"Main Rotor Blade Secondary Bolt Locking","sectionType":"part","heading":"Main Rotor Blade Secondary Bolt Locking","content":"## Main Rotor Blade Secondary Bolt Locking","sortOrder":2},{"sectionNumber":"10/2007","sectionType":"part","heading":"10/2007","content":"## 10/2007","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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — a specific mechanical fix for a specific helicopter model. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (under 200 words of substantive content)","Only 1 defined term implicitly referenced (the helicopter model)","No nested conditional logic — single compliance requirement with one deadline","No cross-references to other Australian legislation — only references to foreign AD and manufacturer bulletin","Single applicability criterion (all BO 105 helicopters)","No exceptions or exemptions stated"],"plain_english_summary":"Mandates installation of a lockwasher on the secondary main-rotor-blade bolt of MBB BO 105 helicopters in Australia to prevent bolt loosening and potential in‑flight blade loss. Affects all BO 105 owners/operators; adopts the manufacturer's lockwasher fix instead of earlier lockwire. Compliance was required before 27 October 2007; the AD references Transport Canada AD CF-88-18 and MBB ASB-BO-105-10-101 Rev 3."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Scope aligns with prior foreign airworthiness directives (German LBA and Transport Canada) and applies to all MBB BO 105 helicopters; it does not expand applicability beyond that fleet, but it delegates technical implementation to the referenced foreign AD and manufacturer bulletin."},"complexity_factors":["Single, discrete technical requirement (secure main rotor secondary bolt) rather than broad regulatory overhaul","Cross-reference to external documents (Transport Canada AD CF-88-18) rather than embedding full technical instructions","Reference to manufacturer service bulletin (MBB ASB-BO-105-10-101 Rev 3) creates dependency on another document for implementation details","Universal applicability to the entire BO 105 fleet simplifies target population but concentrates compliance on all operators","Fixed compliance and effective dates create clear but time‑bound administrative pressure"],"plain_english_summary":"Requires owners/operators of all MBB (Messerschmitt‑Bölkow‑Blohm) BO 105 helicopters to secure the main rotor blade secondary bolt by following Transport Canada AD CF‑88‑18 (manufacturer ASB MBB ASB‑BO‑105‑10‑101 Rev 3 is referenced). Compliance deadline: 27 October 2007; effective 27 September 2007.\n\nIt addresses anti‑rotation of the secondary bolt (Germany’s LBA had required lockwire; MBB developed a lockwasher). The operator pays for the modification; CASA enforces compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bo-105-23-main-rotor-blade-secondary-bolt-locking","history":"/api/acts/ad-bo-105-23-main-rotor-blade-secondary-bolt-locking/history","analysis":"/api/acts/ad-bo-105-23-main-rotor-blade-secondary-bolt-locking/analysis","conflicts":"/api/acts/ad-bo-105-23-main-rotor-blade-secondary-bolt-locking/conflicts","importantCases":"/api/acts/ad-bo-105-23-main-rotor-blade-secondary-bolt-locking/important-cases","documents":"/api/acts/ad-bo-105-23-main-rotor-blade-secondary-bolt-locking/documents"}}