Both the Federal Aviation Administration and the National Transportation Safety Board are investigating the crash of a single-engine aircraft that went down in a pineapple field a mile south of Wheeler Army Airfield yesterday with two men on board. The aircraft was originally reported to be a helicopter, but the FAA provided updated information on the crash this morning. A civilian pilot reported engine trouble to the Wheeler Army Airfield control tower just before the crash. He and a passenger got out of the aircraft on their own. Federal firefighters  provided medical treatment at the scene and transported the pilot and passenger to an area hospital for further evaluation and medical treatment.