The pilot took off to conduct a low level aerobatic display. Shortly after lift off, at a very low height, he rolled the aircraft inverted. He applied forward elevator to hold the nose up to avoid a descent. At that point a blanking nut came off the top of the canopy and the pilot instinctively reached for it. As he did so, he inadvertanly allowed the aircraft to descend inverted onto the runway surface. While still inverted the aircraft slid to a stop on the runway. Significant Factors The following factors were considered relevant to the development of the accident: 1 The presence of the loose blanking nut. 2 Low height of the aircraft. 3 The pilot allowed himself to be distracted from his primary task of flying the aircraft, at a crucial stage of the flight.