Kratos Defense & Security Solutions Inc. said on Dec. 23 that it received a contract modification worth $13 million to build helicopter simulators for the U.S. Navy.

Kratos (Nasdaq: KTOS) said its simulators provide a blend of virtual and physical environments for training air crews.

The business will build the trainers in Florida and New York. Work is expected to last through early 2018.

Work is on a previously awarded contract.