{"id":"F2009L03440","name":"AD/DHC-8/151 - Spoiler Upload Valves and Rudder Shutoff Valves","slug":"ad-dhc-8-151-spoiler-upload-valves-and-rudder-shutoff-valves","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":141064,"registerId":"commonwealth-F2009L03440-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bombardier (Boeing Canada/De Havilland) ","sectionType":"division","heading":"Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes","content":"### Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\n| AD/DHC-8/151 | Spoiler Upload Valves andRudder Shutoff Valves | 10/2009 |\n| ------------ | ---------------------------------------------- | ------- |\n\n| Applicability: | Bombardier Inc. Models DHC-8-400, DHC-8-401 and DHC-8-402, Serial Numbers (S/N) 4105 through 4179.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Spoiler Unload Valve Manifold - Applicable to DHC-8 Aircraft, Models 400, 401, and 402, S/N 4105 through 4172:Inspect the left hand and right hand spoiler unload valves Part Number (P/N) 396000-1005 for leaking or weeping in accordance with Bombardier Service Bulletin (SB) 84-27-37, dated 5 February 2009, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.a. If leaking or weeping is found, replace the affected spoiler unload valve with a new valve.b. If no leaking or weeping is found, replace the inspected valve(s).2. Rudder Shutoff Valve Manifold - Applicable to DHC-8 Aircraft, Models 400, 401, and 402, S/N 4113 through 4179:Inspect the left hand and right hand rudder shutoff valves P/N 412700-1001 for leaking or weeping in accordance with Bombardier SB 84-27-39, dated5 February 2009, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.a. If leaking or weeping is found, prior to further flight, replace the affected rudder shutoff valve with a new valve.b. If no leaking or weeping is found, replace the inspected valve(s).3. No replacement of Spoiler Unload Valves Assembly P/N 396000-1005, with serial numbers from 0289 through 0424 and Rudder Shutoff Valves P/N412700-1001 with S/N from 0239 through 0384, are allowed to be installed on the DHC-8 Series 400 aeroplanes unless such valves have been inspected by the manufacturer and labelled with a suffix “A” after the S/N as indicated in the above-mentioned Service Bulletins.Note: Transport Canada AD CF-2009-25R1 dated 23 July 2009 refers. |\n\n| Compliance: | For Requirement 1 - Within 750 flight hours after the effective date of this AD.For Requirement 1.a. - Prior to further flight.For Requirement 1.b. - Within 6,000 flight hours from the time of initial inspection mandated by this AD.For Requirement 2 - Within 750 flight hours after the effective date of this AD.For Requirement 2.a. - Prior to further flight.For Requirement 2.b. - Within 6,000 flight hours from the time of initial inspection mandated by this AD.For Requirement 3 - As of the effective date of this AD. |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|             | This Airworthiness Directive becomes effective on 24 September 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| Background: | During final Acceptance Test Procedure, a small oil leak was discovered on the Spoiler Unload Valve and Rudder Shutoff Valve bodies. Investigation revealed that a number of valves were manufactured with an incorrect wall thickness. This thin wall condition caused cracking, subsequent external weeping and pressure loss from the subject valves.This condition, if not corrected, will cause a loss of hydraulic fluid and subsequent loss of spoiler and/or rudder control.                                                     |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n14 August 2009","sortOrder":0},{"sectionNumber":"AD/DHC-8/151","sectionType":"part","heading":"AD/DHC-8/151","content":"## AD/DHC-8/151","sortOrder":1},{"sectionNumber":"Spoiler Upload Valves andRudder Shutoff ","sectionType":"part","heading":"Spoiler Upload Valves andRudder Shutoff Valves","content":"## Spoiler Upload Valves and  \nRudder Shutoff Valves","sortOrder":2},{"sectionNumber":"10/2009","sectionType":"part","heading":"10/2009","content":"## 10/2009","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":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific manufacturing defect in specific valve part numbers on specific aircraft serial numbers. The document has not expanded beyond its original safety purpose."},"complexity_factors":["Short, single-purpose document with clear mechanical focus","Only 2 main technical requirements with straightforward conditional logic (if leaking → replace immediately; if not → replace later)","Limited applicability: 3 specific aircraft models with defined serial number ranges","Simple compliance timeline based on flight hours and effective date","One cross-reference to Canadian aviation authority (Transport Canada) for approved service bulletin revisions","No nested definitions or extensive interpretation sections"],"plain_english_summary":"CASA orders mandatory inspections and timed replacements on Bombardier DHC‑8‑400/-401/-402 (serials 4105–4179) to address spoiler and rudder valve parts with excessively thin walls that can crack and leak hydraulic fluid.  \n\nOperators must inspect within 750 flight hours and replace leaking valves immediately or replace non‑leaking valves within 6,000 hours; certain valve serials are barred unless factory‑repaired and re‑marked. It affects operators of these Q400s in Australia because hydraulic loss could impair spoiler or rudder control and threaten safe handling."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"Scope remains targeted to DHC‑8 Series 400 aeroplanes within the serial-number ranges listed and to the two specified valve P/Ns, addressing valves with incorrect wall thickness. The AD does not expand beyond those aircraft, parts or the remedial actions set out in Requirements 1–3 (Applicability; Requirements 1–3)."},"complexity_factors":["Narrow aircraft and serial-number applicability increases administrative tracking (Applicability: S/N 4105–4179; Requirement 1: S/N 4105–4172; Requirement 2: S/N 4113–4179).","Multiple part numbers and part-specific actions: Spoiler unload valves P/N 396000-1005 and rudder shutoff valves P/N 412700-1001 require different inspections and replacement rules (Requirement 1 & 2).","Staggered compliance windows create operational scheduling complexity: prior-to-flight replacement for leaking valves, inspection within 750 flight hours, and blanket replacement within 6,000 flight hours (Compliance).","Installation prohibition tied to manufacturer re-inspection and labelling (suffix “A”) imposes supply-control and documentation burdens on operators and maintainers (Requirement 3).","Procedural reliance on manufacturer Service Bulletins and on approval by the Chief, Continuing Airworthiness (discretion for later revisions) introduces regulatory dependency and some decision-maker discretion (Requirements 1 & 2 reference Bombardier SB and approval).","Safety-critical failure mode: hydraulic fluid loss can cause loss of spoiler and/or rudder control, so inspections and replacements are time-sensitive and affect flight safety risk management (Background).","Cost and logistics fall on aircraft operators: inspections, component replacements, grounding for repairs, and inventory control for prohibited S/N parts create direct maintenance costs and operational disruption (Requirements & Compliance)."],"plain_english_summary":"- This Airworthiness Directive requires owners/operators of Bombardier DHC‑8‑400 series aeroplanes (specified serial numbers) to inspect specified spoiler unload and rudder shutoff valves for leaks and to replace leaking or inspected valves within set timeframes. It also prohibits installation of certain valve serial numbers unless re‑inspected and relabelled “A”.\n\n- The directive responds to valves made with incorrect wall thickness that can leak hydraulic fluid and risk loss of spoiler or rudder control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-151-spoiler-upload-valves-and-rudder-shutoff-valves","history":"/api/acts/ad-dhc-8-151-spoiler-upload-valves-and-rudder-shutoff-valves/history","analysis":"/api/acts/ad-dhc-8-151-spoiler-upload-valves-and-rudder-shutoff-valves/analysis","conflicts":"/api/acts/ad-dhc-8-151-spoiler-upload-valves-and-rudder-shutoff-valves/conflicts","importantCases":"/api/acts/ad-dhc-8-151-spoiler-upload-valves-and-rudder-shutoff-valves/important-cases","documents":"/api/acts/ad-dhc-8-151-spoiler-upload-valves-and-rudder-shutoff-valves/documents"}}