In 2014, the Army began implementing a plan to move all Apaches from the Army Reserve and National Guard to the active Army to serve as scout helicopters to replace the OH-58 Kiowa. Using the AH-64 to scout would be less expensive than Kiowa upgrades or purchasing a new scout helicopter. AH-64Es can control UAVs like the MQ-1C Grey Eagle to perform aerial scouting missions; a 2010 study found the teaming of Apaches and UAVs was the most cost-effective alternative to a new helicopter and would meet 80 percent of reconnaissance requirements, compared to 20 percent with existing OH-58s and 50 percent with upgraded OH-58s. National Guard units, who would lose their attack helicopters, criticized the proposal. In March 2015, the first heavy attack reconnaissance unit was formed with 24 Apaches and 12 Shadow UAVs.