WEST CHICAGO, Ill. (AP) _ A medical helicopter practicing maneuvers at a suburban county airport crashed into a snow-covered farm field, authorities said.

DuPage Airport spokesman Brian Kulpin said at least one person was killed in the Tuesday night crash.

``It had just taken off just a few moments before,'' Kulpin said. ``At this point it appears only one person was on board, but the there may have been more.''

West Chicago police officer Mike Rosenwinkel said the department received a call about the crash around 9 p.m.

The crash occurred on airport property in a farm field about two miles south of its runways, Kulpin said.

Kulpin said weather conditions were snowy and wet, but he didn't know if that contributed to the accident.

The helicopter was with Air Angels medivac service and was affiliated with Good Samaritan Hospital in suburban Downers Grove, hospital administrator Sue Sullivan said.

The helicopter was not flying to or from the hospital at the time of the crash, she said.

``It is our group, our people, but it did not leave from our hospital,'' she said. ``We know all of them so we're worried trying to find out who was working.''

Typically, the crew would consist of a pilot and two others, Sullivan said, adding that an ambulance crew from the hospital was dispatched to the scene.

The Federal Aviation Administration and the National Transportation Safety Board were at the scene.