{"id":"F2005L02073","name":"AD/BELL 206/159 - Torque Indicators","slug":"ad-bell-206-159-torque-indicators","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":36272,"registerId":"commonwealth-F2005L02073-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bell Helicopter Textron Canada (BHTC) 20","sectionType":"division","heading":"Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters","content":"### Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters\n\n| AD/BELL 206/159 | Torque Indicators | 9/2005 |\n| --------------- | ----------------- | ------ |\n\n```html\n

Applicability:

Bell Helicopter Textron Canada (BHTC) model 206B and 206BL4 helicopters as follows:

Model

206B

206L4

Serial Numbers

254 through 4585 and 5101 through 5305 inclusive
52001 through 52301 inclusive and 52303

Requirement:

1. Unless already accomplished, verify the part number of the installed engine torque indicator in accordance with BHTC Alert Service Bulletin (ASB) 206-05-104 or 206L-05-133, as applicable, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

2. If, as a result of the Requirement 1 inspection, a torque indicator with part number (P/N) 206-075-739-123 or P/N 206-075-739-125 has been identified, replace the torque indicator in accordance with instructions provided in ASB 206-05-104 or 206L-05-133, as applicable, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Note: Transport Canada AD CF-2005-22 refers.

Compliance:

For Requirements 1 and 2 - Before 30 November 2005.

This Airworthiness Directive becomes effective on 1 September 2005.

Background:

Transport Canada has received advice from BHTC that due to manufacturing discrepancies, the performance of torque indicators manufactured by Ahlers Aerospace in cold weather may be affected resulting in lower than actual readings.

This Directive requires the inspection of all installed torque indicators to determine their part number and, if necessary, their replacement.

\n```\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n22 July 2005","sortOrder":0},{"sectionNumber":"AD/BELL 206/159","sectionType":"part","heading":"AD/BELL 206/159","content":"## AD/BELL 206/159","sortOrder":1},{"sectionNumber":"Torque Indicators","sectionType":"part","heading":"Torque Indicators","content":"## Torque Indicators","sortOrder":2},{"sectionNumber":"9/2005","sectionType":"part","heading":"9/2005","content":"## 9/2005","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, targeted airworthiness directive addressing a specific manufacturing defect in a particular component. The scope remains precisely limited to the identified safety issue with torque indicators on the specified helicopter models."},"complexity_factors":["Single, clearly defined applicability table with specific model numbers and serial number ranges","Two straightforward sequential requirements (inspect, then replace if necessary)","Only 2 specific part numbers trigger the replacement requirement","Single compliance deadline for all requirements","No defined terms section, no cross-references to other legislation beyond a reference to the Canadian authority's equivalent directive","Background explanation is concise and directly supports the technical requirement"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of certain Bell 206B (S/N 254–4585, 5101–5305) and 206L4 (S/N 52001–52301, 52303) helicopters to inspect their engine torque indicators and replace affected Ahlers Aerospace units. Some gauges can read falsely low in cold weather, risking engine over‑stress. Follow Bell’s service bulletin to check part numbers and replace faulty gauges before 30 November 2005 (effective 1 September 2005)."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD remains narrowly focused on identifying and replacing specific torque indicator part numbers on defined Bell 206B and 206L4 serial-numbered helicopters because of a cold-weather performance concern. It does not broaden regulatory obligations beyond that original safety objective, nor does it add unrelated requirements or expanded applicability."},"complexity_factors":["Short instrument with two operative Requirements (inspect; replace if specific P/Ns found)","Two specified helicopter models and explicit serial number ranges for applicability","Two specific part numbers identified for mandatory replacement (P/N 206-075-739-123 and 206-075-739-125)","Cross-reference to manufacturer Alert Service Bulletins (ASB 206-05-104 and 206L-05-133) for procedural detail","Provision allowing later ASB revisions only if approved by the Chief, Continuing Airworthiness, Transport Canada (adds limited external discretion)","Single compliance deadline and an effective date (simple temporal requirement)","Reference to a related Transport Canada AD (CF-2005-22) but no complex conditional exceptions or nested criteria"],"plain_english_summary":"**What this instrument does (mechanically):**\n\n- This Airworthiness Directive (AD) requires operators of specified Bell 206B and 206L4 helicopters to inspect the installed engine torque indicator to confirm its part number, and to replace the torque indicator if it is one of two specific part numbers (P/N 206-075-739-123 or P/N 206-075-739-125).\n- The inspection and any replacement must be done following the instructions in the relevant Bell Helicopter Textron Canada (BHTC) Alert Service Bulletin (ASB 206-05-104 for 206B or ASB 206L-05-133 for 206L4) or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.\n- Applicability is limited to Bell 206B (serial no. 254–4585 and 5101–5305) and 206L4 (serial no. 52001–52301 and 52303) helicopters.\n- The AD set a compliance deadline for these actions (inspection and replacement if necessary) to be completed before 30 November 2005 and became effective on 1 September 2005.\n\n**Why the regulator issued this AD (official rationale):**\n\n- Transport Canada advised that torque indicators manufactured by Ahlers Aerospace, because of manufacturing discrepancies, may give lower-than-actual torque readings in cold weather. The AD's stated purpose is to identify any affected indicators and replace them so torque readings remain accurate.\n\n**Who is affected and who decides/controls compliance:**\n\n- Primary responsibility: the registered owners/operators of the affected Bell 206B and 206L4 helicopters. They must arrange the inspection and any replacement.\n- Approved maintenance organisations, independent maintenance shops or Bell service centres will typically perform the inspection and replacement under the ASB instructions.\n- The Civil Aviation Safety Authority (CASA) enforces the AD in Australia; the AD also relies on BHTC ASBs and approvals from Transport Canada for later revisions.\n\n**Practical mechanics and compliance burden:**\n\n- Action required: a visual/identification inspection to read the torque indicator part number, followed by replacement only if the indicator is one of the two listed P/Ns.\n- Time and cost: inspection is brief and low-cost; replacement incurs parts and labour costs and aircraft downtime. The AD does not mandate replacement of all indicators—only those with the two specific P/Ns—so costs are limited to affected units.\n- Implementation risk: limited to parts availability and scheduling downtime. The AD cross-references manufacturer ASBs and requires Transport Canada approval for later ASB revisions, which introduces some dependency on manufacturer/regulator action for technical instructions.\n\n**Trade-offs, incentives and likely distribution of costs/benefits:**\n\n- Who pays: helicopter owners/operators pay for inspections and replacement parts and for any associated downtime.\n- Who benefits: operators benefit from corrected torque readings (safety and maintenance accuracy); parts suppliers and maintenance providers may gain business from replacements.\n- Concentrated benefits/costs: the cost per affected helicopter can be concentrated on its owner; the safety benefit is broadly diffuse (reduced risk of torque-related engine/drive problems across the fleet).\n- Opportunity costs: time and money spent on inspection/replacement could otherwise be used for other maintenance, but the AD makes this work mandatory.\n\n**Regulatory discretion and cross-jurisdictional aspects:**\n\n- The AD requires compliance with specific BHTC ASBs or later revisions approved by Transport Canada. That cross-reference gives some practical discretion to the foreign regulator/manufacturer for the detailed work instructions and creates dependence on their revision process.\n\n**Effects on markets and operators (market-liberal lens):**\n\n- Competition and independent business: Independent maintenance providers remain able to carry out the inspection/replacement under the ASB, so the AD does not restrict who can do the work; it may increase business for maintenance shops and parts distributors.\n- Prices and productivity: operators face a one-off or intermittent cost and small productivity loss from downtime; accurate torque readings may avoid larger downstream maintenance costs, so there is a potential offset in avoided failures.\n- Contract freedom/ownership: the AD imposes a compliance obligation on owners/operators, limiting their ability to defer or avoid the specified maintenance for safety/regulatory reasons.\n\n**Net procedural summary:**\n\n- Inspect torque indicator part number using the BHTC ASB (or approved later revision).\n- If P/N is 206-075-739-123 or 206-075-739-125, replace the torque indicator per the ASB.\n- Complete these steps by the stated compliance date.\n\n(Reference details: models and serial number ranges and the two P/Ns are listed in the AD; the AD notes Transport Canada AD CF-2005-22 as a related instrument.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-159-torque-indicators","history":"/api/acts/ad-bell-206-159-torque-indicators/history","analysis":"/api/acts/ad-bell-206-159-torque-indicators/analysis","conflicts":"/api/acts/ad-bell-206-159-torque-indicators/conflicts","importantCases":"/api/acts/ad-bell-206-159-torque-indicators/important-cases","documents":"/api/acts/ad-bell-206-159-torque-indicators/documents"}}