The AN/URT-44 locator beacon used by the U.S. Air Force has failed to work in 10 out of 22 ejections.
When tested on the shelves, the device has a 24 percent failure rate.
[thumb]http://www.militarytimes.com/article/20140205/NEWS/302050028/Locator-beacons-Air-Force-ejection-seats-failing-unacceptable-rate[/thumb]