In service experience, repair and evolution of EC135 m/r blade towards the DMC benchmark

Abstract

Since decades now the EC 135 BMR (Bearingless Main Rotor) technology has proven its outstanding performance not only in service but also regarding low DMC (Direct Maintenance Cost) values. Although the first produced blades have shown some areas of improvement, the blade is now in an extremely mature and reliable state with still decreasing DMCs for customers. In addition small changes in manufacturing and design lead to important improvements regarding maintenance and inspection criteria for the customer, therefore an overview about trim tab design, sealing concepts, trailing edge and surface protection will be given. A further topic will be the various "In Service Evaluations", their results and final implementation in the manufacturing and / or maintenance of the main rotor blade and the valuable customer inputs. Additionally new repair and repair processes had to be implemented for the unique design of the rotor system and have further increased the Airbus Helicopters portfolio of repairs in quality, size and quantity. The paper will give an overview of the technical improvements performed to increase customer satisfaction and ease and reduce the DMCs spent on the main rotor blade, as the protection against erosion environment, like rain and sand, with a metallic erosion shield in connection with other protective measures against particle impacts.