CHARLOTTE, N.C. (AP) — An employee of regional carrier Piedmont Airlines has died in Charlotte after the baggage-hauling tug he was driving flipped, pinning him underneath.

The accident Sunday night at Charlotte Douglas International Airport occurred on the ramp, an area restricted to planes and service vehicles. Airport officials said in a statement that the man was taken to a hospital, where he died.

A spokeswoman for the North Carolina Department of Labor said Monday that the agency has opened an investigation that is likely to take several months.

American Airlines, which owns Piedmont, declined to identify the man. An airline spokeswoman said American was focusing on helping his family and co-workers.

Piedmont operates many American Eagle flights in Charlotte, a major hub for American.