L-3 Communications Vertex Aerospace, LLC, Madison, Miss., is being awarded an $18,530,000 modification to a previously awarded indefinite-delivery requirements contract (N00019-05-D-0023) to exercise an option for logistics support for TH-57B/TH-57C aircraft. Â Work will be performed at Naval Air Station (NAS) Whiting Field, Milton, Fla. (99 percent), and NAS Patuxent River, Md. (1 percent). Â Work is expected to be completed in March 2011. Â Contract funds will not expire at the end of the current fiscal year. Â The Naval Air Systems Command, Patuxent River, Md., is the contracting activity.