On September 6, 1999, at 0700 central daylight time, a Rockwell International S-2R agricultural airplane, N4919X, was destroyed during an aborted takeoff following a loss of engine power near Lookeba, Oklahoma. The airplane was registered to and operated by the pilot. The airline transport rated pilot, sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 137 aerial application flight, and no flight plan was filed. The local flight was originating from a private grass airstrip at the time of the accident. According to the pilot, during the engine start, "the engine was a little harder to crank than normal." He reported that "on the run-up before takeoff the engine spit, backfired, and then cleared up." He initiated the takeoff roll and "everything was fine for a few seconds," and then "about half way down the runway the engine coughed, spit, and backfired again." He stated that smoke was coming from the engine compartment and then smoke entered the cockpit. The pilot aborted the takeoff, and subsequently, the airplane departed the end of the runway and rolled into a ditch. The pilot exited the airplane and observed "flames emitting from the front section of the engine, near the carburetor." Subsequently, the airplane was consumed by a fire. The pilot/operator removed and examined the engine oil sump from the Pratt and Whitney R-1340-AN1 engine. He observed "numerous pieces and shavings" of ferrous metal. He added in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that the pieces resembled cylinder parts. No further examination was conducted.