The pilot was undergoing a check flight with an instructor. The strip in use was positioned at the top of a ridge, with landings being made into a 20 knot wind. The approach to the strip passed over powerlines, which were some 200 metres prior to the normal touchdown point. The aircraft was positioned on final approach with dive brakes fully extended. However, the pilot allowed the airspeed to decay and, despite repeated instructions from the instructor to increase the airspeed, he failed to respond. The aircraft sank below the required approach path. The instructor attempted to correct the undershoot by closing the dive brakes, but was too late to prevent the aircraft entering a downdraft created by the wind curling over the ridge. The aircraft struck the powerlines with the left wing and canopy, which shattered on impact. The pilot received an electric shock and burns to the head. The aircraft then fell to the ground and came to rest adjacent to the powerlines.