{"id":"F2005L02397","name":"AD/B737/110 Amdt 2 - Rudder Yaw Damper Valve Replacement","slug":"ad-b737-110-amdt-2-rudder-yaw-damper-valve-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":36850,"registerId":"commonwealth-F2005L02397-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/110 Amdt 2 | Rudder Yaw Damper Valve Replacement | 10/2005 |\n| ------------------ | ----------------------------------- | ------- |\n\n| Applicability: | Model 737-100, -200, -300, -400, and -500 series aeroplanes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Unless already accomplished, perform a one time inspection of the engage solenoid valve of the yaw damper to determine the Part Number (P/N) of the valve.2. If any valve having one of the following part numbers is installed;Parker P/N 59600-5011 (Boeing P/N 10-60811-9); orParker P/N 59600-5007 (Boeing P/N 10-60811-3 (see Note 3)); orParker P/N 59600-5003 (Boeing P/N 10-60811-1).replace it with one of the following valves;Parker P/N 881600-1001 (Boeing P/N 1060811-13), orSterer P/N 45080-1 (Boeing P/N 10-60811-8), orSterer P/N 45080 (Boeing P/N 10-60811-3 (see Note 3).The above actions are to be accomplished in accordance with procedures specified in Chapter 22-11-61 or Chapter 22-12-21 (for 737 -100 and -200 series aircraft) of the Boeing Maintenance Manual as applicable; or Chapter 22-12-21 (for 737-300, -400, and -500 series aircraft) of the Boeing Maintenance Manual.Accomplishment of the requirements of AD/B737/201 (FAA AD 2002-20-07) constitutes terminating action for the requirements of this Directive.Note 1. FAA AD 97-09-15 R1 Amdt 39-10912 refers.Note 2. Boeing In-Service Activities Report 95-03-2725-10 dated 16 February 1995 (for model 737-100 and -200 series aircraft), or 95-04-2725-10, dated 24 February 1995 (for Model 737-300, -400 and -500 series aircraft) provide additional information concerning interchangeability of solenoid valve part numbers. |\n\n|             | Note 3. Operators should note that, as identified above, two Parker and Sterer Part Numbers have the same Boeing Part Number (10-60811-3). If, upon inspection, Boeing Part number 10-60811-3 is found to be installed, operators must ascertain the vendor part number. Parts with Boeing P/N 10-60811-3 and Parker P/N 59600-5007 must be replaced and are not considered to be acceptable replacement parts. In addition, some engage solenoid valves may be labelled with only the name “Bertea”, rather than “Parker” or “Parker-Bertea”.                                                                                                                                                                                                                                |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1. Within 5 years or 15,000 flights after 25 February 1999 or at the next time the PCU is removed for maintenance, whichever is the earlier.2. Before further flight.The compliance times remain unchanged by this issue.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n|             | This Amendment becomes effective on 29 September 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n| Background: | Investigation into the Boeing 737 flight control system has revealed system anomalies, which, if not corrected, could lead to reduced controllability or uncommanded control input. This Directive was issued as a direct result of these investigations to remove a potential source of failure within the yaw system.Amendment 1 clarified component identification and reflected the requirements of the Country of Origin Aviation Authority.Amendment 2 is issued in response to FAA AD 2002-20-07, which requires incorporation of a new rudder control system; which when incorporated, supersedes the requirements of AD 97-09-15 R1, the Requirement document of this Directive.The original issue of this Airworthiness Directive became effective on 17 July 1997. |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n19 August 2005","sortOrder":0},{"sectionNumber":"AD/B737/110 Amdt 2","sectionType":"part","heading":"AD/B737/110 Amdt 2","content":"## AD/B737/110 Amdt 2","sortOrder":1},{"sectionNumber":"Rudder Yaw Damper Valve Replacement","sectionType":"part","heading":"Rudder Yaw Damper Valve Replacement","content":"## Rudder Yaw Damper Valve Replacement","sortOrder":2},{"sectionNumber":"10/2005","sectionType":"part","heading":"10/2005","content":"## 10/2005","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":3,"scope_assessment":{"changed":false,"description":"Amendment 2 does not materially broaden the Directive's operational scope (it still targets the same 737 series and the same solenoid-valve failure mode). It clarifies component identification (to resolve vendor/Boeing part number ambiguity) and aligns the AD with FAA AD 2002-20-07 by identifying that accomplishment of that FAA AD constitutes terminating action. In practice this adds an alternative compliance pathway (installing a new rudder control system) but does not expand the class of aircraft or add new mandatory tasks beyond clarification and the existing inspection/replacement requirement."},"complexity_factors":["Applies to five 737 model groups (-100, -200, -300, -400, -500)","Multiple vendor and Boeing part numbers to check (at least six vendor P/Ns listed and overlapping Boeing P/Ns)","Conditional compliance timing (within 5 years or 15,000 flights after 25/02/1999 or at next PCU removal, whichever is earlier)","Immediate replacement requirement if an unacceptable part is found (\"before further flight\")","Cross-references to Boeing Maintenance Manual chapters and other ADs (FAA AD 2002-20-07, earlier ADs and in-service reports)","Ambiguity risk: two vendor parts share one Boeing P/N (10-60811-3), requiring vendor-level identification"],"plain_english_summary":"**What this instrument does (mechanics)\n\n- This Airworthiness Directive (AD) applies to Boeing 737-100, -200, -300, -400 and -500 series aeroplanes.\n- It requires a one‑time inspection of the yaw damper's engage solenoid valve to read the vendor part number (Parker, Sterer or similar). If the valve installed is one of three identified Parker part numbers that are associated with a known problem, the valve must be replaced with one of three specified acceptable replacement valves.\n- The work must be done using the Boeing Maintenance Manual procedures referenced (Chapter 22-11-61 or 22-12-21 as applicable). Completing the modification required by FAA AD 2002-20-07 (installation of a new rudder control system) will terminate the need to comply with this Directive.\n\n**Who this affects\n\n- Aircraft operators and maintenance organisations that operate or maintain Boeing 737-100 through -500 series aeroplanes.\n- Parts suppliers and maintenance planners who source and log solenoid valves for the yaw damper system.\n\n**Deadlines and compliance mechanics\n\n- Inspection: must be done within 5 years or 15,000 flights after 25 February 1999, or at the next time the Power Control Unit (PCU) is removed for maintenance — whichever is earlier.\n- Replacement: if an unacceptable valve is found, it must be replaced before further flight.\n- The Directive remains effective until the operator implements the FAA AD 2002-20-07 modification (new rudder control system), which is stated as terminating action for the AD's requirements.\n\n**Why the regulator requires this\n\n- The stated purpose is to remove a potential source of failure in the rudder/yaw system identified during investigations. The Directive presents that the specific vendor part numbers are associated with anomalies that could produce reduced controllability or uncommanded inputs.\n\n**Practical effects, incentives and costs\n\n- Who pays: the operator pays for the inspection and any necessary replacements, plus aircraft downtime and maintenance labour.\n- Who decides: the operator and its authorised maintenance organisations perform the inspection and replacement according to the Boeing Maintenance Manual; the Civil Aviation Safety Authority enforces compliance through the AD.\n- Behaviour change: operators must inspect affected aircraft and replace specific parts where found. Operators may instead choose to install the FAA‑specified rudder control system modification (terminating action), which may require greater upfront cost but removes the need for the specific valve replacement.\n- Market effects: demand for acceptable replacement valves and for the FAA modification increases. Smaller operators with older 737s bear concentrated replacement and downtime costs; parts suppliers of the banned valves lose future demand.\n\n**Trade‑offs, implementation risk and compliance burden\n\n- Trade‑offs: replacing the valve is a targeted, lower‑cost fix; installing the new rudder control system (FAA AD) is a broader modification that eliminates this AD but costs more up front.\n- Implementation risks: part identification is nontrivial because two different vendor parts can share the same Boeing part number (Boeing P/N 10-60811-3). The AD explicitly requires operators to determine the vendor part number where Boeing P/N 10-60811-3 is fitted. Some valves may be labelled only with an alternate vendor name (\"Bertea\"), increasing the chance of misidentification and unnecessary or missed replacements.\n- Compliance burden: a one‑time inspection across an entire fleet and replacement where necessary. Records must show vendor part numbers and that replacements were carried out when required.\n\n**Notes and cross-references\n\n- The Directive references Boeing In-Service Activities Reports for interchangeability details and refers to earlier FAA and CASA ADs. Operators should follow the specific Boeing Maintenance Manual chapters cited when carrying out the work (Chapter 22-11-61 or 22-12-21).\n\n(Claims about safety benefits are made by the regulator as the rationale for the AD; measured benefits depend on actual failure rates and the effectiveness of the replacement or the FAA modification.)"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"Originally issued in 1997 to address specific valve failures, the directive has expanded through two amendments. Amendment 1 clarified component identification. Amendment 2 (this version) adds a terminating action provision referencing a completely new rudder control system (AD/B737/201), effectively acknowledging that the original valve-specific fix became obsolete when a more comprehensive system redesign was mandated. The scope shifted from 'replace this specific valve' to 'replace this valve OR install the new rudder system' — a significant expansion that incorporates a superseding technical solution."},"complexity_factors":["Multiple overlapping compliance deadlines (5 years OR 15,000 flights OR next PCU removal)","Critical part number confusion: same Boeing P/N (10-60811-3) used by two different manufacturers with opposite compliance outcomes","Cross-reference to three other documents (FAA AD 97-09-15 R1, FAA AD 2002-20-07, and Boeing In-Service Activities Reports)","Different maintenance manual chapters apply to different aircraft sub-models (-100/-200 vs -300/-400/-500)","Terminating action clause (compliance with later AD/B737/201 satisfies this directive)","Vendor name variations to identify (Parker, Parker-Bertea, or Bertea labelling)"],"plain_english_summary":"This AD mandates inspection and, if necessary, replacement of specific Parker/Bertea solenoid valves in the rudder yaw damper on Boeing 737 Classic (-100 to -500) aircraft to remove a failure mode that can cause uncommanded rudder movement. Operators and maintenance crews must verify the vendor-stamped part number (not just Boeing’s) because one supplier’s valve is unsafe. Compliance is due within specified flight/time limits or at next PCU removal; earlier AD/B737/201 compliance is acceptable."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-110-amdt-2-rudder-yaw-damper-valve-replacement","history":"/api/acts/ad-b737-110-amdt-2-rudder-yaw-damper-valve-replacement/history","analysis":"/api/acts/ad-b737-110-amdt-2-rudder-yaw-damper-valve-replacement/analysis","conflicts":"/api/acts/ad-b737-110-amdt-2-rudder-yaw-damper-valve-replacement/conflicts","importantCases":"/api/acts/ad-b737-110-amdt-2-rudder-yaw-damper-valve-replacement/important-cases","documents":"/api/acts/ad-b737-110-amdt-2-rudder-yaw-damper-valve-replacement/documents"}}