Private equity firm Kohlberg Kravis Roberts & Co. LP (NYSE: KKR) is buying Air Medical Group Holdings from Bain Capital and Brockway Moran & Partners.

Lewisville, Texas-based Air Medical provides emergency transportation services to people with critical health problems or injuries who are too far away from hospitals to be transported by ground. The company moves more than 75,000 patients every day via helicopters and airplanes. The company also provides ground transportation. Terms of the transaction are not disclosed. Mergers & Acquisitions reported the business was for sale in February. 

KKR has worked with both helicopter companies and health care companies. The firm invested in HCA Corp., a health care services business, in 2006. KKR has been invested in Westar Aviation, a helicopter business, since 2013.

New York-based KKR is making the investment primarily from its North America XI Fund. The deal is expected to close in the second quarter.

The firm's other recent deals include portfolio company Alliant Insurance Services' deal for Kassa Insurance Services Inc., earlier in March, and the acquisition of rail ticket seller Thetrainline.com in January. 

Boston-based Bain has been invested in Air Medical since 2010. Bain's other recent deals include the purchase of TI Automotive in January. In August, the firm bought a 50 percent stake in Toms Shoes Inc. 

Brockway Moran, a Boca Raton, Florida-based private equity firm, has raised more than $1.3 billion in capital.

Barclays acted as financial adviser, and Kirkland & Ellis LLP provided legal advice to Air Medical. Simpson Thacher & Bartlett LLP acted as KKR's legal counsel. Morgan Stanley, Jefferies and KKR Capital Markets are providing debt financing.