Downloaded from https://www.everyspec.com ADS-79D-HDBK Once a CI alert threshold is verified and validated as mature via statistics, the engineers‘ scoring of hardware condition from TDAs should match that of the aircraft HUMS or ground based station display output. D.5 APPROACH: CI/HI DEVELOPMENT FOR LEGACY AIRCRAFT D.5.1 Initial situation. The following section provides an example application of concepts defined in this Appendix pertaining to a fault in a gearbox. a. An existing Army aircraft system with existing vibration based data collection system. b.
The Intermediate Gearbox (IGB) on the tail boom experiences a rash of failures related to a crack on the input side of the gearbox (closest to transmission), specifically in the input bevel gear. Reference Figure D-3 for example. c. Because of safety implications and insufficient utility of current vibration monitoring practice to detect the crack in time, the program office decides to explore developing a new or modified CI which can detect the crack more effectively, and begin to establish conservative estimates of remaining useful life. FIGURE D-3. Example of an input bevel gear fault D.5.2 CI development process.
Figures D-4, D-5, and D-6 overview the process and tools needed to develop CI/HIs 84