{"id":"F2007L02133","name":"AD/BELL 222/36 - Tail Rotor Driveshaft Thomas Couplings","slug":"ad-bell-222-36-tail-rotor-driveshaft-thomas-couplings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":67294,"registerId":"commonwealth-F2007L02133-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bell Helicopter Textron Canada (BHTC) 22","sectionType":"division","heading":"Bell Helicopter Textron Canada (BHTC) 222 Series Helicopters","content":"### Bell Helicopter Textron Canada (BHTC) 222 Series Helicopters\n\n| AD/BELL 222/36 | Tail Rotor Driveshaft Thomas Couplings | 8/2007 |\n| -------------- | -------------------------------------- | ------ |\n\n| Applicability: | Bell Helicopter Textron Canada (BHTC) Model 222 helicopters serial number (S/N) up to 47089; andModel 222B helicopters S/N up to 47156; andModel 222U helicopters S/N up to 47574. |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Verify Disc Assemblies for manufacturing date, proper thickness and indexing, in accordance with instructions provided in applicable Alert Service Bulletins (ASB) listed below or later NAA approved revisions.- 222 and 222B ASB-222-07-105 dated 28 March 2007.- 222U ASB-222U-07-76 dated 28 March 2007.2. For Disc Assemblies held as spares.(a) If manufacturing date is not between 1 November 2005 and 30 November 2006, the Disc Assemblies do not require further action.(b) If required, adjust the thickness of Disc Assemblies by removing or adding a new disc.(c) If required, re-index Disc assembly in accordance with the applicable Maintenance Manual.(d) Attach to Disc Assembly a serviceable tag with inscription indicating compliance to the applicable ASB.3. For Disc Assemblies installed in an aircraft.(a) Remove from service any Disc Assembly which is not within the required thickness as per the table below. |\n\n```html\n

Disc Assembly

Part Number

Total Thickness

Minimum

Maximum

36300-1

0.174 inch (4.42 mm)

0.186 inch (4.75 mm)

37855-1

0.126 inch (3.20 mm)

0.138 inch (3.50 mm)

(b) Remove any Disc Assembly which is not properly indexed.

(c) If Disc Assemblies do not require further action or the manufacturing date is not between 1 November 2005 and 30 November 2006, make an appropriate log book notation to this effect.

Note: Transport Canada AD CF-2007-09 dated 17 May 2007 refers.

Compliance:

1. Not later than 25 flight hours or 30 days from the effective date of this directive whichever occurs first.

2. Before fitment to an aircraft after the effective date of this AD.

3. a. Within 10 flight hours from the effective date of this AD.

3. b. Within 300 flight hours from the effective date of this AD or at the next scheduled inspection, whichever occurs first.

3. c. Following the verification of the Disc Assembly.

This Airworthiness Directive becomes effective on 2 August 2007.

Background:

It has been determined that certain Disc Assemblies as listed in this AD manufactured between 1 November 2005 through 30 November 2006, may have insufficient amount of discs or may have been indexed incorrectly.

\n```\n\n![](image.001.png) \nDavid Punshon \nDelegate of the Civil Aviation Safety Authority\n\n19 June 2007","sortOrder":0},{"sectionNumber":"AD/BELL 222/36","sectionType":"part","heading":"AD/BELL 222/36","content":"## AD/BELL 222/36","sortOrder":1},{"sectionNumber":"Tail Rotor Driveshaft Thomas Couplings","sectionType":"part","heading":"Tail Rotor Driveshaft Thomas Couplings","content":"## Tail Rotor Driveshaft Thomas Couplings","sortOrder":2},{"sectionNumber":"8/2007","sectionType":"part","heading":"8/2007","content":"## 8/2007","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"},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The directive does not expand or narrow scope beyond its stated intent in the text: it applies to specified Bell 222/222B/222U serial numbers and targets Disc Assemblies manufactured between 1 Nov 2005 and 30 Nov 2006, requiring inspection and remedial action per the named ASBs. No indication in the instrument that scope was altered from the original corrective purpose."},"complexity_factors":["Technical measurement thresholds: tight total thickness tolerances for two Disc Assembly part numbers (36300‑1: 0.174–0.186 in; 37855‑1: 0.126–0.138 in) increase measurement and calibration demands.","Applicability limited by serial number ranges for three submodels (222, 222B, 222U) and by manufacturing date window (1 Nov 2005–30 Nov 2006), requiring record checks and parts traceability.","Multiple remedial options and operations (verify date, re‑index, add/remove discs, remove from service) impose judgement and parts availability issues for maintenance providers.","Cross‑references to manufacturer Alert Service Bulletins (ASB‑222‑07‑105; ASB‑222U‑07‑76) and the Maintenance Manual create layered compliance obligations and potential for versioning ambiguity.","Staged compliance schedule with several different deadlines (e.g. 25 flight hours or 30 days; before fitment; within 10 flight hours; within 300 flight hours or next inspection) increases planning and recordkeeping complexity.","Different rules for installed assemblies versus spares (including tagging and log‑book notation) create separate workflows and administrative burden.","Regulatory linkage to a foreign AD (Transport Canada CF‑2007‑09) adds cross‑jurisdictional reference and potential differences in interpretation."],"plain_english_summary":"This Airworthiness Directive requires operators of specified Bell 222, 222B and 222U helicopters (listed by serial number) to inspect tail‑rotor driveshaft Thomas coupling Disc Assemblies for manufacturing date, thickness and correct indexing, and to adjust, tag, log or remove non‑conforming assemblies per the listed Bell Alert Service Bulletins. It became effective 2 August 2007. Operators pay for inspections, parts and removals; CASA enforces staged compliance deadlines and requires log‑book entries for compliant or exempt parts."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a focused, single-purpose scope: addressing a specific manufacturing defect in a particular helicopter component. The scope remains tightly constrained to the identified safety issue without expansion into broader operational or maintenance requirements."},"complexity_factors":["Multiple applicability categories (3 helicopter models with different serial number cutoffs)","Nested conditional requirements (different rules for spare parts vs installed parts)","Specific dimensional tolerances with dual measurement systems (imperial and metric)","Multiple compliance deadlines depending on action type (flight hours vs calendar days vs scheduled inspections)","Cross-reference to external technical documents (Alert Service Bulletins and Maintenance Manuals)","Date-range exceptions (manufacturing window of 1 Nov 2005–30 Nov 2006)","Table-based technical specifications for two different part numbers"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection and, if necessary, repair or removal of Tail Rotor Driveshaft Thomas Coupling disc assemblies on Bell 222, 222B and 222U helicopters after certain parts made Nov 2005–Nov 2006 may have incorrect disc count or alignment. It affects owners/operators and spare parts holders and aims to prevent tail rotor failure—and possible loss of control—by ensuring suspect couplings meet required thickness and indexing before further use."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-222-36-tail-rotor-driveshaft-thomas-couplings","history":"/api/acts/ad-bell-222-36-tail-rotor-driveshaft-thomas-couplings/history","analysis":"/api/acts/ad-bell-222-36-tail-rotor-driveshaft-thomas-couplings/analysis","conflicts":"/api/acts/ad-bell-222-36-tail-rotor-driveshaft-thomas-couplings/conflicts","importantCases":"/api/acts/ad-bell-222-36-tail-rotor-driveshaft-thomas-couplings/important-cases","documents":"/api/acts/ad-bell-222-36-tail-rotor-driveshaft-thomas-couplings/documents"}}