{"id":"F2009L00503","name":"AD/PR/33 Amdt 3 - Hub Assembly","slug":"ad-pr-33-amdt-3-hub-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":77142,"registerId":"commonwealth-F2009L00503-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Propellers - Variable Pitch - Dowty Roto","sectionType":"division","heading":"Propellers - Variable Pitch - Dowty Rotol","content":"### Propellers - Variable Pitch - Dowty Rotol\n\n| AD/PR/33 Amdt 3 | Hub Assembly | 3/2009 |\n| --------------- | ------------ | ------ |\n\n| Applicability: | Dowty Aerospace Propellers Models R389/4-123-F/25, R389/4-123-F/26 and R390/4-123-F/27 propellers, all serial numbers, fitted with Part Number (P/N) 660714241 or P/N 660714255 hub assemblies, including P/N 660714241 hub assemblies that have been reworked in accordance with Dowty drawing 660714259.Note 1: These propellers are known to be installed on Saab SF340A and 340B aircraft. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Inspect the propeller hubs in accordance with the instructions of Dowty Propellers ASB SF340-61-95.Inspections and corrective actions accomplished prior to the effective date of this AD, in accordance with Dowty ASB SF340-61-95 at original issue or Revision 1 or Revision 2 or Revision 3 or Revision 4, are acceptable to comply with the initial requirements of paragraph (1) of this AD. After the effective date of this AD, repetitive inspections and corrective actions must be accomplished in accordance with Dowty ASB SF340-61-95 at Revision 5.2. Send an inspection report to Dowty Propellers in accordance with paragraph 2.B of Dowty ASB SF340-61-95.3. When cracks are detected during any inspection as required by this AD, replace the hub with a serviceable unit. Replacement of the hub does not constitute terminating action for the repetitive inspection requirements of this AD.The use of later approved revisions of these documents is acceptable for compliance with requirements of this AD.Terminating ActionModification of the affected propellers in accordance with Dowty Service Bulletin (SB) SF340-61-105 (at any revision) constitutes terminating action for the repetitive inspection requirements of this AD.Note 2: EASA AD 2009-0005 dated 8 January 2009 refers. This AD supersedes CAA UK AD 006-10-99. |\n\n| Compliance: | For Requirement 1 - Within 1,200 Flight Hours (FH) after 24 February 2000 (the original issue of this AD) and thereafter at intervals not to exceed 1,200 FH.For Requirement 2 - Within 30 days after each inspection as detailed in Requirement 1 of this AD.For Requirement 3 - Before further flight. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Amendment becomes effective on 12 March 2009. |\n| Background: | Current propeller maintenance philosophy recognizes the possibility of hub cracks and the need for Non-Destructive Testing (NDT) checks. This condition, if not detected and corrected, could cause premature failure of a propeller hub, resulting in propeller detachment and consequent damage to and loss of control of the aircraft.The standard time between overhaul (TBO) for Dowty R389 and R390 propeller hubs has been established at 7,500 flight hours (FH), when hubs must be scanned for cracks in accordance with the applicable Dowty Component Maintenance Manual (CMM). The CMM describes the so-called ‘B scan’ NDT method, which is not convenient for aircraft operators to perform. To adequately address this safety issue, Dowty published Alert Service Bulletin (ASB) SF340-61-95 that describes additional NDT checks that can be accomplished by the aircraft operator.In October 1999, the UK Civil Aviation Authority (CAA) mandated the accomplishment of these NDT checks by issuing AD 006-10-99 (CASA AD/PR/33 Amendments 1 and 2). In January 2008, Dowty revised the ASB to update and improve the inspection methods that must be used for crack detection.For the reasons described above, this AD retains the requirements of UK CAA AD 006-10-99, which is superseded, and requires the inspection of the propeller hub rear half wall in accordance with the revised method(s) as published by Dowty Propellers.Amendment 2of this AD reduced the compliance intervals from 1,800 FH to 1,200 FH.Amendment 1 of this AD extended the compliance interval and the repetitive inspection intervals from 1,600 FH to 1,800FH.Amendment 2 of this AD became effective on 23 January 2003.Amendment 1 became effective on 28 December 2000. |\n\n| | The original issue of this AD became effective on 24 February 2000. |\n| --- | ------------------------------------------------------------------- |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n27 January 2009","sortOrder":0},{"sectionNumber":"AD/PR/33 Amdt 3","sectionType":"part","heading":"AD/PR/33 Amdt 3","content":"## AD/PR/33 Amdt 3","sortOrder":1},{"sectionNumber":"Hub Assembly","sectionType":"part","heading":"Hub Assembly","content":"## Hub Assembly","sortOrder":2},{"sectionNumber":"3/2009","sectionType":"part","heading":"3/2009","content":"## 3/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Compared with the original AD (effective 24 February 2000), the instrument’s operational scope has been adjusted: compliance intervals were changed by previous amendments (notably reduced to 1,200 flight hours) and the current amendment mandates repetitive inspections using Dowty ASB SF340‑61‑95 Revision 5 for ongoing checks. The AD retains the original inspection mandate but updates methods, intervals and specifies that modification per Dowty SB SF340‑61‑105 constitutes terminating action (see 'Requirement' and 'Compliance' and 'Background' sections)."},"complexity_factors":["Technical NDT requirements (B‑scan and operator‑performable checks) and the need for competent inspection methods","Multiple referenced documents and acceptable revisions (Dowty ASB SF340‑61‑95 multiple revisions, Dowty SB SF340‑61‑105)","Precise applicability limited to specific propeller models, serial numbers and hub part numbers","Layered compliance regime: initial and repetitive inspections, reporting obligation, mandatory replacement for cracks, and a separate terminating modification","Changing compliance intervals across earlier amendments (history of 1,600 → 1,800 → 1,200 flight hours) adding operational planning complexity","Reporting timelines (30 days) and immediate grounding requirement when cracks are found (replace before further flight)","Cross‑jurisdictional references (EASA and prior UK CAA AD) increasing regulatory cross‑checks"],"plain_english_summary":"This AD requires regular non‑destructive inspections of certain Dowty variable‑pitch propeller hub assemblies (P/N 660714241, 660714255 and reworked 660714241) installed on Saab SF340 aircraft, following Dowty ASB SF340‑61‑95. Reports of inspections must be sent to Dowty, cracked hubs must be replaced before further flight, and modification under Dowty SB SF340‑61‑105 stops the need for repetitive checks.\n\nInspections recur every 1,200 flight hours with 30‑day reporting; the measure addresses the risk that undetected hub cracks could cause propeller detachment and loss of control."},"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":4,"scope_assessment":{"changed":false,"description":"This legislation maintains its original scope as a targeted safety directive for specific propeller hub assemblies. While Amendment 3 updates inspection methods and references (superseding earlier UK and CASA directives), it does not expand beyond the original purpose of ensuring airworthiness of Dowty propeller hubs on Saab 340 aircraft. The amendment history shows refinement of compliance intervals (reduced from 1,800 to 1,200 flight hours) and inspection procedures, but the core scope remains consistent with the original February 2000 directive."},"complexity_factors":["Multiple amendment history requiring cross-referencing (Amendments 1, 2, and 3 with different effective dates and compliance intervals)","Specific part number identification required (P/N 660714241, P/N 660714255, plus reworked units per drawing 660714259)","Document version control complexity (acceptance of ASB revisions 1-4 for prior compliance, but Revision 5 required going forward)","Conditional compliance logic (different timeframes for initial vs. repetitive inspections, plus terminating action conditions)","Cross-references to international aviation safety regulations (EASA AD 2009-0005, UK CAA AD 006-10-99)"],"plain_english_summary":"This CASA Airworthiness Directive mandates mandatory non‑destructive inspections, reporting, and replacement of certain Dowty propeller hub assemblies used on Saab 340A/B aircraft to prevent hub cracking and potential propeller detachment. It affects operators and maintenance organisations of Saab 340s with the specified Dowty propellers and requires ongoing inspections until a Dowty modification is embodied that terminates the repetitive checks."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pr-33-amdt-3-hub-assembly","history":"/api/acts/ad-pr-33-amdt-3-hub-assembly/history","analysis":"/api/acts/ad-pr-33-amdt-3-hub-assembly/analysis","conflicts":"/api/acts/ad-pr-33-amdt-3-hub-assembly/conflicts","importantCases":"/api/acts/ad-pr-33-amdt-3-hub-assembly/important-cases","documents":"/api/acts/ad-pr-33-amdt-3-hub-assembly/documents"}}