{"id":"F2006B06330","name":"AD/PR/32 - Blade Pitch Seizure","slug":"ad-pr-32-blade-pitch-seizure","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47496,"registerId":"commonwealth-F2006B06330-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PR/32 - Blade Pitch Seizure","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPropellers \\- Variable Pitch \\- Dowty Rotol\n\nAD/PR/32 Blade Pitch Seizure 4/97\n\nApplicability: All R/354/4-123-F/13, R354/4-123-F/20, R375/4-123-F/21, R389/4-123-F/25,\n\nR389/4-123-F/26 or R390/4-123-F/27 propellers fitted to SAAB 340 A or B series aircraft.\n\nRequirement: Modify or de-modify (as applicable) the propeller pitch change mechanism in accordance with Dowty Aerospace Mandatory SB SF340-61-88 dated Jan 23/97.\n\nNote: UK CAA AD 002-11-96 dated 2 November, 1996, refers.\n\nCompliance: Unless previously carried out, incorporate as specified in the Requirement Document paragraph D.\n\nThis Airworthiness Directive becomes effective on 27 March 1997.\n\nBackground: The manufacturer has advised that during ground running a propeller which had recently been modified to SB SF340-61-79 status, suffered a seizure of the propeller pitch change. This occurred when the slide block, attached to the crosshead by coiled springs, became detached and allowed the crosshead to turn and contact the blade root inner sleeves which then locked the propeller blades in a fixed position.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1083},"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow technical scope addressing a specific mechanical defect (slide block detachment) in identified propeller models fitted to SAAB 340 aircraft. No expansion beyond the original safety purpose is evident."},"complexity_factors":["Multiple specific part numbers listed in applicability (6 distinct propeller models)","Reference to external technical document (Dowty Aerospace Mandatory Service Bulletin SF340-61-88)","Technical aviation terminology requiring engineering knowledge (crosshead, slide block, pitch change mechanism, blade root inner sleeves)","Conditional compliance requirement ('Unless previously carried out')","Cross-reference to UK Civil Aviation Authority directive (UK CAA AD 002-11-96)"],"plain_english_summary":"**What this does:** This is a safety order (called an Airworthiness Directive) that requires aircraft operators to fix a dangerous mechanical flaw in certain propellers fitted to SAAB 340 aircraft.\n\n**Who it affects:** Owners and operators of SAAB 340 A and B series aircraft that have specific Dowty Rotol propeller models (R/354/4-123-F/13, R354/4-123-F/20, R375/4-123-F/21, R389/4-123-F/25, R389/4-123-F/26, or R390/4-123-F/27).\n\n**What must be done:** Operators must modify or reverse a previous modification to the propeller's pitch change mechanism according to the manufacturer's Service Bulletin SF340-61-88 dated 23 January 1997.\n\n**Why it matters:** The propeller's slide block (a component held by coiled springs) can detach during operation. If this happens, the crosshead (a connecting part) can twist and jam against the blade root, locking the propeller blades in a fixed position. This \"pitch seizure\" could cause loss of control or engine damage during flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pr-32-blade-pitch-seizure","history":"/api/acts/ad-pr-32-blade-pitch-seizure/history","analysis":"/api/acts/ad-pr-32-blade-pitch-seizure/analysis","conflicts":"/api/acts/ad-pr-32-blade-pitch-seizure/conflicts","importantCases":"/api/acts/ad-pr-32-blade-pitch-seizure/important-cases","documents":"/api/acts/ad-pr-32-blade-pitch-seizure/documents"}}