The UAS consists of miniature, unmanned helicopters that are approximately 5-feet long and able to fly for about 15 minutes on battery power. The APD has been operating a UAS program for several years. After completing 2 years of testing, evaluation, and training, the APD received from the Federal Aviation Administration its official Certificate of Authorization (COA) to operate a UAS. The APD was one of the first law enforcement agencies located in a densely populated urban area to receive a COA. The CAO restrictions include flying under 400 feet from the ground only in daylight within sight of the operator and a safety observer at all times. It must also maintain contact with the control tower of a specified airport. In addition, the system may not be used for pursuit or traffic enforcement. Within these challenging restrictions, the APD reports being able to use the UAS program for accident and crime-scene reconstruction and the search for missing persons. One of the first cases that used an unmanned helicopter involved the exterior observation of an active-shooter barricade. All officers who operate the helicopters are licensed pilots, because all flights occur in controlled airspace.