Detection of a fatigue crack in a UH-60A planet gear carrier using vibration analysis

Two new methods of detecting a fatigue crack in a planet carrier of an epicyclic transmission are developed. These are tested using vibration data from a number of US Army UH-60A Black Hawk helicopter main transmissions. Vibration measurements of faulted and un-faulted transmissions over a range of torque levels in controlled test-cell and on-aircraft conditions are used. The results show that new methods are reliable under test-cell conditions, but less effective under low-torque on-aircraft conditions.