Marines with the 11th Marine Expeditionary Unit disembark helicopters lining up for fuel April 3 at Castle Airport. Twelve helicopters, eight transporting infantrymen, stopped here en route to a simulated raid site during the MEU's recent air-ground task force exercise held at several California installations. - Marines with the 11th Marine Expeditionary Unit disembark helicopters lining up for fuel April 3 at Castle Airport. Twelve helicopters, eight transporting infantrymen, stopped here en route to a simulated raid site during the MEU's recent air-ground task force exercise held at several California installations.