On takeoff from runway 29 at Juliaca Airport (JUL), Peru, the aircraft rotated, got airborne but failed to gain height. Gear was selected up, flaps retracted, but also power was retarded. The aircraft crossed the end of the runway and went very low over about 1800 m of flat hard soil, then impacted on a road which was about .8 m above the flat terrain with gulleys on either side of about 0.7 m deep. After several further impacts, it came to rest in a riverbed about 220 m from the road, about 1.5 m below the flat terrain. The aircraft came to rest in several parts. The front fuselage had separated from the centre fuselage near the wing front spar and came to rest inverted, about 50 m from the aft fuselage. The lower fuselage of this section was damaged and crushed from the radome rearwards with progressively more damage further aft, towards the break. However, survival space in this section was basically not compromised. Most seats were still fully attached to the floor with only some fracture at/near the floor break. The centre wing section, still connected to the right hand wing was badly damaged. The left hand wing had separated. The fuselage skin and top skin were torn from the centre section. A large number of broken seats and interior parts were found in an area aside the centre wing, presumably ejected from the centre wing/fuselage area upon impact with the sand in the river bed. Most of the fatalities were found here. Structural integrity of the aft fuselage, which had separated from the centre wing section, was entirely lost. Although still grouped together, both engines had separated from the tail, and the fin showed unusually severe damage. The occupants of the inverted forward section either evacuated on their own through the open end at the rear or with the assistance of others. It is believed that all of the occupants of the centre and aft cabin section were ejected.