The pilot was flying the twin engine airplane in the traffic pattern for a fly-by event at an air show. Two fly-by circuits had been completed, and the airplane was on the third downwind leg at an estimated altitude of 600 to 800 feet AGL when the right engine lost power. The main landing gear had been previously extended, and the pilot elected not to retract the landing gear in anticipation of landing on the runway. The pilot reported that he performed emergency procedures by pushing the throttles forward and attempting to restart the right engine. The right engine did not restart, and the airplane collided with terrain short of the runway. The pilot did not claim to have feathered the inoperative right engine's propellers. Postaccident inspection of the right engine revealed no evidence of preimpact anomaly. The right engine's magnetos and carburetor were damaged and not functionally tested. The propeller of the right engine was found in an unfeathered, fine pitch position.