TransDigm Group Inc. [TDG] on Tuesday said it has agreed to acquire the independent engineering company Calspan Corp.

in a deal that will add transonic wind tunnels and testing and technology services mainly for aerospace and defense customers.

Terms of the deal were not disclosed. TransDigm said the pending acquisition is subject to regulatory approvals and is expected to close during its fiscal year that ends in September. Calspan is based in Buffalo, has about 625 employees, and expects to generate about $200 million in sales this year.

Calspan has multiple wind tunnels that operate from subsonic to hypersonic to produce data for customers, and jet-powered airborne testbeds to test support services for all programs, including autonomous flight testing. The company also performs propulsion testing for various jet engines and offers a range of capabilities in hypersonics, from early-stage research and development to supporting full-scale flight demonstrator programs, and has a team of experimental test pilots, mechanics and technicians.

“We see opportunity for TransDigm’s proven operating model to enhance the company’s established positions across a diverse range of aftermarket-focused aerospace and defense development and testing services,” Kevin Stein, president and CEO of TransDigm, said of Calspan in a statement. “The company operates within our primary aerospace and defense industry and its unique service offerings exhibit the earnings stability and growth potential that we have come to expect of our aerospace components-centered businesses.”

Sheila Kahyaoglu, an aerospace and defense analyst who follows TransDigm for the investment firm Jefferies, pegged the acquisition price at about $700 million in a note to clients on Tuesday.

Calspan is privately owned by co-chairmen John Yurtchuk and Lou Knotts. Houlihan Lokey is Calspan’s financial adviser on the transaction.