The DC-8 took off for an empty positioning flight from Asuncion runway 02. At VR power was reduced on no. 1 engine and, after rotation, also on the no. 2 engine. With the gear still down and flaps at 15ø the pilot lost control and crashed on a playing field 2 km past the runway. PROBABLE CAUSE: Violent collision with the ground with post-impact fire due to loss of control of the aircraft in flight caused by procedures incorrectly performed by the crew during the critical takeoff phase, the effects of which resulted in an extremely adverse configuration of the aircraft for that phase of flight, which could not be counteracted and control of the aircraft was lost, resulting in a significant reduction in speed and subsequent loss of lift. Contributing Factors: 1 Little experience of the pilot in command in this function 2 Lack of flight safety doctrine in the cockpit at all pre-flight times. 3 Probable execution of unauthorized take-off training under uncontrolled conditions and by a person not qualified as an instructor. 4 Probable lack of knowledge of the flight characteristics with an empty aircraft on the part of the crew.