{"id":"F2006L00354","name":"AD/F50/93 - Propeller Blade De-icer Boot","slug":"ad-f50-93-propeller-blade-de-icer-boot","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116961,"registerId":"commonwealth-F2006L00354-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Fokker F50 (F27 Mk 50) Series Aeroplanes","sectionType":"division","heading":"Fokker F50 (F27 Mk 50) Series Aeroplanes","content":"### Fokker F50 (F27 Mk 50) Series Aeroplanes\n\n| AD/F50/93 | Propeller Blade De-icer Boot | 3/2006 |\n| --------- | ---------------------------- | ------ |\n\n| Applicability: | Fokker Aircraft B.V. Model F27 Mark 050, Mark 0502 and Mark 0604 aircraft equipped with Dowty Propellers (formerly Dowty Aerospace Gloucester) Type R.352 or R.410 series propellers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Check the maintenance records to determine whether Minnesota Mining and Manufacture Co. (3M) 1300L adhesive has been used to fit the de-icer assemblies (boots) to the propeller blades. If it has been positively established that Bostik 2402 adhesive has been used, no further action is required by this directive.2. If 3M 1300L adhesive has been used, inspect the propeller blade de-icer assemblies (boots) in accordance with the accomplishment instructions of Dowty Propellers Service Bulletin (SB) F50-61-158 dated 30 September 2005 or a later EASA-approved revision.3. When, during the inspection in accordance with requirement 2 of this AD, any signs of lifting or bubbling are found, replace the affected de-icer boot in accordance with Dowty Propellers Specification PS 5723 (attached to DowtySB F50-61-158 as Appendix 1), latest revision.4. 3M 1300L adhesive not to be used to fit de-icer boots to propeller blades on Fokker F27 Mark 050, 0502 and 0604 series aircraft.Note: CAA Netherlands AD NL-2005-016 EASA approval No. 2005-6448 dated15 December 2005 refers. |\n| Compliance:    | 1. Within 30 days after the effective date of this directive.2. Within the next 650 flight hours after the effective date of this directive, and thereafter at intervals not exceeding 650 flight hours.3. Before next flight.4. As of the effective date of this directive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n|                | This Airworthiness Directive becomes effective on 16 March 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n\n| Background: | Since May 2003, there have been three events with Fokker 50 (F27 Mark 050) aircraft, where the propeller blade de-icer assembly overshoe (boot) detached during flight. Two impacted the fuselage, causing considerable damage but did not penetrate, one hit a passenger cabin window, shattering the pane and penetrating into the fuselage, thereby injuring two passengers. All of the affected boots had been fitted using 3M 1300L adhesive. A thorough safety analysis has shown that this condition, if not corrected, could result in a hazardous event, including the possibility of passengers being seriously or fatally injured. Since an unsafe condition has been identified that may exist or develop on aircraft of the same type design, this AD requires a repetitive inspection of the propeller blade de-icer assembly. In addition, the continued use of 3M 1300L adhesive for fitting propeller blade de-icer boots is no longer authorized. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n1 February 2006","sortOrder":0},{"sectionNumber":"AD/F50/93","sectionType":"part","heading":"AD/F50/93","content":"## AD/F50/93","sortOrder":1},{"sectionNumber":"Propeller Blade De-icer Boot","sectionType":"part","heading":"Propeller Blade De-icer Boot","content":"## Propeller Blade De-icer Boot","sortOrder":2},{"sectionNumber":"3/2006","sectionType":"part","heading":"3/2006","content":"## 3/2006","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 focused scope on its original safety purpose. It addresses a specific mechanical failure mode (propeller de-icer boot detachment) on a narrow class of aircraft, with requirements tightly calibrated to the identified risk. No scope creep is evident — the directive does not expand into unrelated systems or impose burdens beyond what the safety analysis supports."},"complexity_factors":["Single, specific technical issue with clear causal chain (adhesive → detachment → hazard)","Four distinct but straightforward requirements with explicit deadlines","Only 2 defined technical terms requiring clarification (de-icer boot/overshoe, specific adhesive types)","Single cross-reference to manufacturer service bulletin and Dutch aviation authority AD","No nested exceptions or conditional logic — requirements flow sequentially based on simple binary determination (was 3M adhesive used: yes/no)","Limited applicability: only 3 specific aircraft models with specific propeller types"],"plain_english_summary":"This CASA Airworthiness Directive mandates checks and inspections on Fokker F50 aircraft with certain Dowty propellers after propeller de‑icer boots detached in flight — one event shattered a cabin window and injured passengers. Operators must check maintenance records for 3M 1300L adhesive within 30 days, inspect boots regularly, replace any lifting or bubbling boots before flight, and stop using 3M 1300L. It applies to operators and maintainers of affected F50s."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive addresses an identified unsafe condition for the specified Fokker F27 Mark 050/0502/0604 aircraft with Dowty R.352/R.410 propellers by imposing inspections, replacement requirements, and banning 3M 1300L adhesive. It does not expand applicability beyond the listed models or add unrelated obligations; it confines corrective action to the unsafe condition described (Background; Applicability; Requirement 1–4)."},"complexity_factors":["Narrow applicability: specific airframe models and Dowty propeller types (Applicability).","Multiple procedural requirements: record check, recurring inspections, immediate replacement for defects, and an outright adhesive ban (Requirement 1–4).","Staggered compliance timelines: 30 days, 650 flight-hours recurring interval, and before next flight for defected parts (Compliance).","Reference to external technical documents and revisions: Dowty SB F50-61-158 and Dowty Specification PS 5723 (Requirement 2–3).","Requirement to determine historical adhesive use from maintenance records creates administrative burden and potential for ambiguous record evidence (Requirement 1).","Safety-critical immediate actions (replace before next flight) increase operational disruption risk if defects found (Requirement 3; Compliance).","Dependence on EASA/CAA Netherlands approvals and later approved revisions introduces regulatory coordination and possible interpretation variance (Note; Requirement 2)."],"plain_english_summary":"This Airworthiness Directive requires operators of Fokker F27 Mark 050, 0502 and 0604 aircraft with Dowty R.352/R.410 propellers to check maintenance records for 3M 1300L adhesive, perform recurring inspections of propeller de-icer boots, replace any boots showing lifting or bubbling per Dowty specification, and cease using 3M 1300L to fit boots. It matters because detached boots have previously struck the fuselage and cabin, injuring passengers; the directive assigns the inspection, replacement and adhesive-change duties to aircraft operators and maintainers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-93-propeller-blade-de-icer-boot","history":"/api/acts/ad-f50-93-propeller-blade-de-icer-boot/history","analysis":"/api/acts/ad-f50-93-propeller-blade-de-icer-boot/analysis","conflicts":"/api/acts/ad-f50-93-propeller-blade-de-icer-boot/conflicts","importantCases":"/api/acts/ad-f50-93-propeller-blade-de-icer-boot/important-cases","documents":"/api/acts/ad-f50-93-propeller-blade-de-icer-boot/documents"}}