Demonstration and Analysis of an Improved Nondestructive Evaluation (NDE) Method for Rotary Wing Head Spindle Threads

摘要

Present inspection methods for the Black Hawk helicopter rotary wing head spindle require almost complete disassembly of the rotary wing head and hub assemblies to expose the failure critical threads for inspection. Even with direct access to the threads, detection of fatigue cracks in the thread roots is very difficult using penetrant and visual methods. Therefore, the primary purpose of this project was to demonstrate an improved nondestructive evaluation (NDE) method for the spindle using the electric current perturbation (ECP) method which requires only minimal disassembly for safety-of-flight inspections. High sensitivity inspection of the spindle threads applicable to routine teardown maintenance was also demonstrated. (Author)