Usually a failure in safety-certified systems is acceptable if, on average, less than one life per 109 hours of continuous operation is lost to failure.{as per FAA document AC 25.1309-1A} Most Western nuclear reactors, medical equipment, and commercial aircraft are certified to this level. The cost versus loss of lives has been considered appropriate at this level (by FAA for aircraft systems under Federal Aviation Regulations).
Usually a failure in safety-certified systems is acceptable if, on average, less than one life per 109 hours of continuous operation is lost to failure.{as per FAA document AC 25.1309-1A} Most Western nuclear reactors, medical equipment, and commercial aircraft are certified to this level. The cost versus loss of lives has been considered appropriate at this level (by FAA for aircraft systems under Federal Aviation Regulations)