Staff Sgt. Jacob Merrell, a crew chief with Marine Medium Tiltrotor Squadron 363, 3rd Marine Aircraft Wing, and a Sisters, Ore., native, shoots an M240D machine gun during a tail gun shoot exercise over a range training complex aboard Marine Corps Air station Yuma, Ariz., Oct. 31. Pilots communicate with crew chiefs through an inner communication system, so they know the location of the targets. - Staff Sgt. Jacob Merrell, a crew chief with Marine Medium Tiltrotor Squadron 363, 3rd Marine Aircraft Wing, and a Sisters, Ore., native, shoots an M240D machine gun during a tail gun shoot exercise over a range training complex aboard Marine Corps Air station Yuma, Ariz., Oct. 31. Pilots communicate with crew chiefs through an inner communication system, so they know the location of the targets.