{"id":"F2006B09235","name":"AD/DHC-8/77 - Rudder Pedal Mechanism","slug":"ad-dhc-8-77-rudder-pedal-mechanism","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53127,"registerId":"commonwealth-F2006B09235-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.","sortOrder":0},{"sectionNumber":"AD/DHC-8/77 Rudder Pedal Mechanism 4/200","sectionType":"part","heading":"AD/DHC-8/77 Rudder Pedal Mechanism 4/2001","content":"# AD/DHC-8/77 Rudder Pedal Mechanism 4/2001\n\nApplicability: DHC-8 aircraft, Series 100, 200 and 300, serial numbers 003 to 563.\n\nRequirement: 1. Inspect the rudder pedal adjustment fittings, part number (P/N) 82710038-101, for cracks in accordance with the Accomplishment Instructions contained in Bombardier Alert Service Bulletin (ASB) A8-27-91, dated 12 September 2000.\n\nReplace any cracked fitting before further flight.\n\nWhen performing maintenance checks in response to a reported rudder control system defect which exhibits characteristics such as binding or a change in stiffness of the rudder pedal movement during aircraft operation, inspect the rudder pedal adjustment fitting in accordance with Requirement 1 before further flight.\n\n    2. Fittings may be replaced by either new aluminium fittings, P/N 82710038-01, or steel fitings, P/N 82710080-101, in accordance with the following:\n\n    New aluminium fittings, P/N 82710038-101, must be inspected in accordance with the Accomplishment Instructions of ASB A8-27-91.\n\n    b. Installation of a new steel fitting, P/N 82710080-101, (Bombardier ModSum 8Q101156) constitutes terminating action of this Directive.\n\nNote: Transport Canada AD CF-2001-04 refers.\n\nCompliance: 1. Initially, within 5,000 flight hours since new or within 500 flight hours after the effective date of this Directive, whichever occurs later, and thereafter at intervals not to exceed 1,000 flight hours; and,\n\n2. a. Initially, within 5,000 flight hours after installation and thereafter at intervals not to exceed 1,000 flight hours.\n\nThis Airworthiness Directive becomes effective on 19 April 2001.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope — addressing a specific unsafe condition in a specific aircraft type's rudder pedal mechanism. There is no evidence of scope creep; the document remains tightly focused on the original safety issue identified by the manufacturer and Transport Canada."},"complexity_factors":["Short, single-purpose document focused on one mechanical component","Clear applicability section limiting scope to specific aircraft series and serial numbers","Straightforward two-part requirement structure (inspect/replace)","Simple compliance timeline with basic conditional logic ('whichever occurs later')","Single cross-reference to manufacturer service bulletin (ASB A8-27-91)","Minimal defined terms (only standard aviation abbreviations like P/N for part number)","One nested condition in Requirement 2 regarding terminating action"],"plain_english_summary":"This safety order applies to de Havilland Canada DHC-8 (Dash 8) Series 100–300, serials 003–563, and requires operators to inspect rudder-pedal adjustment fittings for cracks and replace any cracked parts before further flight. Pilots reporting stiff or sticking pedals trigger immediate inspection. Operators can either keep aluminum fittings with recurring inspections or fit steel replacements to terminate repeat checks. The measure prevents loss of rudder control by detecting or eliminating a known fatigue/crack risk."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive stays narrowly focused on addressing cracks in a specific rudder pedal adjustment fitting for a defined set of DHC-8 aeroplanes. It prescribes inspection intervals, immediate replacement of cracked fittings, and offers a terminating modification (steel fitting). There is no evidence in the text that the AD expands beyond its original safety-correction purpose (detect/replace cracked fittings or install a fitting that removes recurring inspections). Any apparent scope ambiguity is operational (part-number clarification and reliance on Bombardier service documents), not a substantive expansion of the AD's safety objective."},"complexity_factors":["Narrow applicability: single aeroplane type (DHC-8 Series 100/200/300) and limited serial number range (003–563)","Two primary requirements only: crack inspection and allowable replacement options","Two compliance timing regimes (initial + repetitive intervals, and initial after-installation + repetitive intervals)","Cross-references to external documents: Bombardier ASB A8-27-91 and Bombardier ModSum 8Q101156 (inspection and terminating modification)","Terminology/part-number ambiguity in the text (similar part numbers 82710038-101 vs 82710038-01) increasing interpretive risk for maintainers","Single explicit terminating action (installation of steel fitting) that changes ongoing obligations"],"plain_english_summary":"**What this directive does (mechanics)\n\n- Requires operators of certain DHC-8 (Dash 8) aeroplanes to inspect a specific rudder pedal adjustment fitting (part number 82710038-101) for cracks and to replace any cracked fitting before the aircraft flies again. (Requirement 1)\n- Requires the same inspection whenever a rudder control system defect is reported that shows binding or a change in pedal stiffness, and again the aircraft must not return to service until the inspection and any necessary replacement are done. (Requirement 1)\n- Allows operators to replace the aluminium fitting with either a new aluminium fitting of the indicated part number or with a steel fitting (P/N 82710080-101). Installing the steel fitting under the referenced Bombardier modification (ModSum 8Q101156) ends the need to keep doing the inspections required by this directive (the steel fitting is a \"terminating action\"). (Requirement 2)\n- Directs operators to follow the inspection procedure set out in Bombardier Alert Service Bulletin (ASB) A8-27-91. The AD also notes a related Transport Canada AD. (Requirement text)\n\n**Who is affected\n\n- This applies to De Havilland Canada DHC-8 (Dash 8) Series 100, 200 and 300 aeroplanes with serial numbers 003 to 563. (Applicability)\n- The immediate operational burden falls on aircraft operators/owners and maintenance organisations who must carry out the inspections and any replacements. The regulator (CASA) enforces the directive. Mechanics and parts suppliers are involved in implementation.\n\n**When the work must be done (timing and intervals)\n\n- Initial inspection: within 5,000 flight hours since new or within 500 flight hours after the AD took effect, whichever is later; then repeat at intervals no greater than 1,000 flight hours. (Compliance, item 1)\n- For fittings installed after the AD, inspect initially within 5,000 flight hours after installation and then every 1,000 flight hours. (Compliance, item 2a)\n\n**Options and consequences\n\n- Operators may keep using the aluminium fittings but must carry out recurring inspections per the ASB. (Requirement 2a)\n- Alternatively, operators can install the steel fitting P/N 82710080-101 per Bombardier ModSum 8Q101156. Once the steel fitting is installed, the recurring inspections required by this AD stop (this is the terminating action). (Requirement 2b)\n\n**Who pays and who decides\n\n- Operators pay the costs of inspections, part replacements, and any aircraft downtime. Maintenance organisations perform the work and follow the ASB procedures. CASA (via the delegate who issued the AD) is the decision-maker enforcing this mandatory action under the Civil Aviation Regulations framework. (Preamble and enforcement reference)\n\n**Costs, incentives and trade-offs (implementation perspective)\n\n- Recurring inspection option: lower upfront cost (keep using aluminium part) but recurring maintenance hours and administrative tracking of flight-hour intervals; potential unscheduled removals if cracks are found (aircraft out-of-service). (Requirement 1; Compliance)\n- Replacement option (steel fitting): higher upfront cost and installation downtime, but it eliminates the recurring inspection requirement (reduces ongoing operating cost and regulatory burden). (Requirement 2b)\n- This creates a clear private-incentive decision for operators: pay more once (and remove recurring inspections) or pay less up-front and accept ongoing inspection costs and risk of part failures.\n\n**Implementation and compliance risks\n\n- The AD cross-references Bombardier ASB A8-27-91 for inspection details; compliance requires access to and correct application of that ASB. (Requirement 1)\n- Availability of replacement parts (particularly steel fittings) will affect how quickly operators can adopt the terminating modification.\n- The text of the AD includes closely similar part numbers for aluminium fittings (82710038-101 and a line mentioning 82710038-01). Operators and maintainers should confirm the correct part number and follow the Bombardier ASB and ModSum instructions to avoid installing the wrong part.\n\n**Source claim and testing it against costs and incentives\n\n- The stated purpose in the AD is to correct an \"unsafe condition\" in the rudder pedal adjustment fitting by detecting and removing cracks or by installing a fitting that removes the need for continuing inspections. Mechanically, the AD enforces detection (inspection) with a clear alternative of a one-time modification that terminates the inspection obligation. The cost structure (recurring inspections versus single retrofit) creates obvious operational incentives described above; implementation depends on part supply and maintenance scheduling. (Requirement sections; Compliance)\n\n**Practical note\n\n- The AD explicitly refers operators to Bombardier ASB A8-27-91 for the inspection method and to Bombardier ModSum 8Q101156 for the terminating modification. It also cites a related Transport Canada AD (CF-2001-04). Operators should follow the ASB and ModSum and confirm part numbers before ordering or installing parts.\n"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-77-rudder-pedal-mechanism","history":"/api/acts/ad-dhc-8-77-rudder-pedal-mechanism/history","analysis":"/api/acts/ad-dhc-8-77-rudder-pedal-mechanism/analysis","conflicts":"/api/acts/ad-dhc-8-77-rudder-pedal-mechanism/conflicts","importantCases":"/api/acts/ad-dhc-8-77-rudder-pedal-mechanism/important-cases","documents":"/api/acts/ad-dhc-8-77-rudder-pedal-mechanism/documents"}}