A test pilot is an aviator who flies new and modified aircraft in specific maneuvers, known as flight test techniques or FTTs, allowing the results to be measured and the design to be evaluated. In the 1950s, test pilots were being killed at the rate of about one a week, but the risks have shrunk to a fraction of that, thanks to the maturation of aircraft technology, better ground-testing and simulation of aircraft performance, fly by wire technology and lately, the use of unmanned aerial vehicles to test experimental aircraft features. Still, piloting experimental aircraft remains more dangerous than most other types of flying.