The aircraft collided with wires and crashed during a training mission. According to one of the CFI's other students, the area in which the crash occurred was regularly used by the CFI for airwork. This airwork was normally performed at about 800 ft AGL. On this day, the aircraft was observed at an altitude estimated as 50 to 200 ft AGL. Some witnesses report the engine running smoothly; others say it was spitting and sputtering. Three witnesses observed the wings 'rocking' from side to side. The aircraft struck a powerline at 69 ft AGL. According to witnesses, the aircraft nosed up and then fell in a near vertical nose down attitude. This accident occurred about 30 to 45 minutes after takeoff for this dual training flight. Post accident examination of the aircraft showed the left fuel tank contained about 11 gallons of fuel. The right tank was empty. The fuel selector was on the left tank. Control cable continuity was verified from the control surfaces to the impact damaged area of the cabin.