{"id":"F2006L03532","name":"AD/PR/36 - Blade Counterweight Capscrew Holes","slug":"ad-pr-36-blade-counterweight-capscrew-holes","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":61072,"registerId":"commonwealth-F2006L03532-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/36 | Blade Counterweight Capscrew Holes | 13/2006 TX |\n| -------- | ---------------------------------- | ---------- |\n\n| Applicability: | All Dowty R321/4-82-F/8, R324/4-82-F/9, R333/4-82-F/12 and R334/4-82-F/13 propellers, if blades are installed with serial numbers (S/N) A156121 through A156132, A156137 through A156160, A156165 to A156168, A156177 through A156184, A156194 and A156196 through A156200.Note 1: These propellers are known to be installed on, but not limited to CASA 212, M7 Aerospace (formerly Fairchild, Swearingen) SA227TT, SA227AT and SA227AC, and BAE Systems (formerly British Aerospace) Jetstream 3100 and 3200 series aeroplanes.                                                                        |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Identify the propeller blades that have a serial number listed in the applicability section of this AD and inspect the affected blades in accordance with Dowty Propellers Alert Service Bulletin (ASB), as applicable.2. If discrepancies are found, re-machine the counterweight attachment holes.Note 2: Contact Dowty Propellers, for advice.3. Do not install any of the listed S/N propeller blades on an aircraft unless the blade has been inspected and, if necessary, reworked in accordance with the requirements of this AD.Note 3: EASA EAD No: 2006-0326-E dated 23 October 2006 refers. |\n| Compliance:    | 1. Before further flight after the effective date of this AD.2. Before further flight after the effective date of this AD.3. From the effective date of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n|                | This Airworthiness Directive becomes effective on 27 October 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n\n| Background: | One propeller blade has recently been identified after delivery from Dowty Propellers where the blade counterweight capscrew holes have not been correctly drilled. If the capscrew holes are not machined to their required depth, it may appear that the capscrew has been correctly assembled, but the counterweight will not be properly retained. This condition, if not corrected, could result in failure (due to fatigue) of one or more capscrews, release of the counterweight during propeller operation and consequent risk of injury to aircraft occupants and persons on the ground. Dowty has concluded that the problem is associated only with blades manufactured between April and July 2006, identified by serial number in the applicability section of this AD. Since an unsafe condition has been identified that is likely to exist or develop on other aircraft that have these propeller blades installed, this AD is issued to require the identification, inspection and, where necessary, rework of the affected propeller blades. |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n25 October 2006","sortOrder":0},{"sectionNumber":"AD/PR/36","sectionType":"part","heading":"AD/PR/36","content":"## AD/PR/36","sortOrder":1},{"sectionNumber":"Blade Counterweight Capscrew Holes","sectionType":"part","heading":"Blade Counterweight Capscrew Holes","content":"## Blade Counterweight Capscrew Holes","sortOrder":2},{"sectionNumber":"13/2006 TX","sectionType":"part","heading":"13/2006 TX","content":"## 13/2006 TX","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":"The AD confines action to blades with the listed serial numbers manufactured in the stated period and requires identification, inspection and rework where needed. The instrument does not expand the listed serial-number scope or add new types of obligations beyond inspection, rework and a prohibition on installation until compliant (Applicability; Requirement; Background)."},"complexity_factors":["Narrowly defined affected items by serial number list increases the administrative identification task (Applicability).","Mandated inspection must follow the manufacturer’s Alert Service Bulletin, creating a dependency on Dowty documentation and procedures (Requirement 1).","Conditional rework (re-machining) requires maintenance capability, tooling and downtime when discrepancies are found (Requirement 2).","Prohibition on installing listed blades unless inspected and reworked imposes operational restrictions and immediate grounding risk for uninspected blades (Requirement 3; Compliance: before further flight).","Short compliance timeline—‘before further flight’—creates scheduling and operational pressure for operators and maintainers (Compliance).","Safety-critical hazard identified: capscrew fatigue and potential counterweight release, which concentrates regulatory attention on mechanical tolerances and quality control (Background).","Advisory/discretionary contact with Dowty for advice introduces an element of external consultation and possible variability in implementation (Requirement 2, Note 2).","Applicability references multiple aircraft types where these propellers are installed, widening the operational footprint despite the limited S/N list (Applicability, Note 1)."],"plain_english_summary":"This directive requires operators and maintainers to identify Dowty propeller blades with specific serial numbers, inspect the counterweight capscrew holes per the Dowty Propellers Alert Service Bulletin, and re-machine any holes that do not meet the specification. It also bans installing listed blades unless inspected and, if necessary, reworked.\n\nIt matters because incorrectly drilled holes can allow capscrew fatigue and counterweight release; operators pay for inspections and any rework and must comply before further flight."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope. It addresses a specific manufacturing quality control failure identified in a discrete batch of propeller blades produced over a 4-month period. The directive does not expand beyond this original safety purpose."},"complexity_factors":["Single, specific technical defect addressed (counterweight capscrew hole depth)","Limited applicability: only 4 propeller models with specific serial number ranges manufactured in a 4-month window","Straightforward three-step requirement: identify, inspect, repair if needed","No nested exceptions or conditional logic — compliance is mandatory and immediate","Minimal cross-referencing (only one external document: Dowty ASB, and one EASA reference for context)","Short document (approximately 400 words) with clear, unambiguous language"],"plain_english_summary":"This AD orders immediate inspection and, if needed, re‑machining of certain Dowty propeller blades manufactured Apr–Jul 2006 (specific serial ranges) to correct undersized counterweight capscrew holes. Affected blades must not be fitted until inspected and repaired. It affects operators/owners of aircraft using Dowty R321/R324/R333/R334 propellers (e.g., CASA 212, SA227, Jetstream 3100/3200) and maintenance personnel. The defect can allow a counterweight to separate in flight, risking aircraft damage, injury, or ground casualties."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pr-36-blade-counterweight-capscrew-holes","history":"/api/acts/ad-pr-36-blade-counterweight-capscrew-holes/history","analysis":"/api/acts/ad-pr-36-blade-counterweight-capscrew-holes/analysis","conflicts":"/api/acts/ad-pr-36-blade-counterweight-capscrew-holes/conflicts","importantCases":"/api/acts/ad-pr-36-blade-counterweight-capscrew-holes/important-cases","documents":"/api/acts/ad-pr-36-blade-counterweight-capscrew-holes/documents"}}