WITNESSES STATED THEY OBSERVED THE AIRPLANE ON THE TAKEOFF ROLL LIFT OFF AT LEAST THREE TIMES. THE AIRPLANE THEN LIFTED OFF, AND ANOTHER PILOT-RATED WITNESS OBSERVED THE AIRPLANE IN AN EXTREMELY NOSE-HIGH ATTITUDE WITH THE ENGINE SOUNDING LIKE IT WAS AT A HIGH POWER SETTING. THE AIRPLANE THEN CRASHED INTO TREES AT THE END OF THE RUNWAY. THE ENGINE AND FLIGHT CONTROLS WERE EXAMINED AND NO PREACCIDENT MALFUNCTIONS WERE FOUND. THE CARGO COULD NOT BE WEIGHED DUE TO POSTCRASH CONSUMPTION. THE SURVIVING PILOT-RATED PASSENGER STATED THAT THE ENGINE LOST POWER AFTER LIFTOFF.