Blade Inspection System

A system to monitor the structural integrity of main rotor blades in service has been developed. The system uses an electrical circuit, applied over the structure of the blade, as its detection means. The electrical system was selected over the differential pressure system because it can be applied to blades in the field by helicopter operators. The paper will describe the laboratory tests to develop the conductor used on the blades, the electronic package comprising the electronic unit, qualification testing and the field service testing used to evaluate the system before production. The system is now in production on new blades and is available as a kit for existing blades. The development of the electronic detector will be discussed. The reason for use of battery power and the means used to obtain many months and thousands of flight hours of battery life will be explained in some detail. Problems encountered during development and the solutions arrived at will be discussed.