The troublesome URT-44 locator beacons, used to find personnel who may have to eject from their aircraft or crash land during peacetime, had been procured from January 2009 to August 2010 to communicate with a new satellite operating frequency.
Col. Aaron Clark, the Global Power Programs Directorate deputy director for Air Force acquisitions, said there has been an increasing number of system failures in the past three years.
Problems include antenna issues, battery reliability and other electrical component problems.
"The beacon is not as reliable as we need it to be," he said. "Right now, we are seeing an observed reliability of about 55 percent."
In a highly accelerated lifecycle test, last year URT-44 systems were put through the most extreme scenarios and environments it could face during an ejection sequence. Clark said there was a 100 percent failure rate among units tested.
The Air Force said beacon replacement has two phases. The first, which has begun, will replace 3,900 beacons on all aircraft with ejection seats by 2015. The cost: $15 million. The second phase will complete fleet-wide replacement and cost about $40 million.