In March 1942, the Navy Bureau of Yards and Docks contracted with Holmes and Narver Consulting Engineers of Los Angeles to design and engineer a Lighter-Than-Air base at Tustin for two airship hangars, and construction began on April 1, 1942. Six months later, Naval Air Station Santa Ana was commissioned on October 1, 1942, and airship operations began with a single blimp using a concrete mat and mooring mast until the hangars were finished the next year. The base, including the hangars, was completed on October 20, 1943, after 18 months and 25 days, at a final cost of $10,062,482.08 rather than the original estimate of about 8 million dollars. By the end of 1942, 12 K-Class blimps were operating from Tustin as Airship Patrol Squadron ZP-31, conducting patrols 24 hours a day. The Lighter-Than-Air fleet achieved an 87 percent on-line and operational rate and flew 89,000 escort missions through submarine-infested waters for ships carrying troops, equipment, and supplies. As sinkings fell from 454 in 1942 to 65 in 1943 and eight in 1944, the need for blimp patrols diminished, and the Tustin facility remained an Lighter-Than-Air base until 1949, when it was decommissioned and redesignated an outlying field. The site had been chosen in Orange County to patrol the southern California coast from San Diego to Santa Barbara, on land negotiated from James Irvine in 1941. Designer-engineer Arsham Amirikian of the Navy Bureau of Yards and Docks created the wooden hangar design that was used for 17 Lighter-Than-Air hangars nationwide. Hangar 1, also called Building 28, was begun in October 1942 and completed in July 1943, and Hangar 2, or Building 29, was begun in December 1942 and completed in September 1943. Built by James I. Barnes Construction Company of Los Angeles, the structures required 2,719,000 board feet of lumber, 79 tons of bolts and washers, 30 tons of ring connectors, and 33 tons of structural steel. The hangars were built in a catenary form, became the world's largest wooden-arch-supported structures, and each was capable of sheltering six Navy K-Class blimps. In 1951, the base was reactivated as Marine Corps Air Facility Santa Ana for the Korean War and became the country's first air facility developed solely for helicopter operations. During the Vietnam War, it served as a center for testing radar installations for shipment to Vietnam. Its name changed to Marine Corps Air Facility Santa Ana in 1969 and Marine Corps Air Station Tustin in 1978. At its peak, the station housed more than 100 helicopters, and it officially closed on July 3, 1999, 57 years after the base and its hangars rose from Orange County farm fields.
