CAMP PENDLETON, Calif. (April 10, 2021) Lance Cpl. Oscar Lopezcux, a maintainer with Marine Unmanned Aerial Vehicle Squadron 4 (VMU-4), performs preflight maintenance on the RQ-21A Blackjack during unmanned air system (UAS) training at Camp Talega, Calif., April 10, 2021. VMU-4 conducts this training in order to enhance aviation mission readiness while refreshing Reserve Marines' knowledge on the RQ-21A UAS and emergency procedures. (U.S. Marine Corps photo by Cpl. J�Vonnta Taylor)