Duc Prop Safety Information
The latest newsletter from Love4Aviation.com includes safety warnings about the use of Duc propellers on direct-drive engines. Love4aviation is a New Zealand-based company that supplies aviation products, including the Dynaero line of aircraft, propellers, silencers, and aircraft management systems. Love4Aviation claims that safety issues related to the use of Duc propellers on Jabiru and other engines have not been effectively communicated to the users. Due to alleged quality control problems and unsatisfactory warranty response, Love4Aviation says it will no longer supply Duc props to clients and have, in its words appearing on the website, "repudiated" the French company Duc Helices.
Persons who purchased a used Duc prop or an airframe with a Duc prop produced prior to 2009 may not be aware of important safety bulletins or operating limitations issued by the manufacturer. The repudiation of Duc props by Love4Aviation also includes technical reports about a variety of problems with individual Duc props it says have not been effectively communicated to customers.
Following an accident, the company Duc Helices sent an e-mail in December 2009 reporting that Jabiru engines shall henceforth use only three-blade propellers and not two-blade propellers. Continued flight with a two-blade Duc propeller on Jabiru engines may present a risk of in-flight breakage, the company reported. In May 2009, following an incident without consequence, Duc Helices conducted some fatigue and mechanical resistance tests. These trials allowed a definite lifetime for Swirl blades, fitted on Jabiru 2200 and 3300 engines. That potential has been evaluated to be 600 hours on direct-drive engines such as Jabiru, ULPower, Continental, Volkswagen, and Limbach, and 800 hours on Rotax and HKS engines. The structural guarantee is 6 months from date of payment. In 2007 Verner Motors issued a statement that use of Duc props on its engines is prohibited and a breach of warranty rules.
Users of Duc props should contact their supplier or airframe manufacturer to determine if there are service bulletins related to their particular prop/engine combination. You can read more about the complaint and see some of the service bulletins at the www.Love4Aviation.com website.