Ultrasonic Measurement Tools and Models for Gearbox Components

The H-60 TGB is a non-redundant, flight-critical component. TGB failures have been responsible for multiple catastrophic aircraft events.Ā However, due to the nature of the part and its location, it is one of the most costly components to inspect. ĀThe inspection itself is not overly difficult, however the process for disassembling and reassembling the tail-rotor to gain access to the area within the TGB for inspection results in significant aircraft down time. One of the most time consuming aspects is the tightening of the inboard retention plate bolts within the TGB assembly which need to be precisely fastened to a specific torque in a particular order, left to ōsettleö then re-torqued before final assembly. Metis Design Corporation developed an ultrasonic washer that couples with embedded data acquisition hardware to detect fatigue cracks in the output bevel gear splines. Further, this system can operate on the ground, so the inspection can take place without disassembly of the TGB or the noise of a flight environment. The same sensors can be used to measure bolt-load. This effort will aim to update the prototype hardware developed in the original Phase II effort, as well as seek to quantify performance and validate results.