The helicopter ended up on its side in a field near Avalon.

AVALON (August 7, 2012)--Two helicopter pilots escaped injury Tuesday in an emergency landing in a rural field northeast of Hillsboro that left the aircraft on its side.

Lynn Lunsford with the Federal Aviation Administration said the helicopter evidently developed a tail rotor problem Tuesday morning.

Lunsford said the chopper sustained substantial damage in the accident.

A Bell Helicopter Textron spokeswoman said the incident happened near Avalon, about 40 miles south of Dallas.

Susan Gordon declined to say whether the Bell 214ST was on a test flight.

Gordon said such helicopters typically take off and land at the company's facility in nearby Arlington.

She said the two pilots were the only people on board.

Gordon declined to release further information on the crew or speculate on what prompted the emergency landing.