Rolls to Buy Jet Engine Rival Allison

British jet engine maker Rolls-Royce will buy competitor Allison Engine Co. for $525 million, the companies announced Monday.

The purchase will allow Rolls-Royce to provide engines to half the markets for military aircraft in the Western World, said John W. Sandford, managing director of Rolls’ aerospace group.

Under the deal, Indianapolis-based Allison, which employs 4,300 people in three Indiana plants, will keep its name. It would be the second sale of Allison in just over a year. General Motors sold the company last fall for $300 million to Clayton, Dubilier & Rice, a New York investment firm, and a group of Allison managers.