On August 18, 1995, at 1405 hours mountain standard time, a Piper PA-28-235, N502MP, collided with the terrain during an emergency landing at Mesa, Arizona. The emergency landing was precipitated by a total loss of power. The pilot was conducting a visual flight rules business flight. The airplane, registered to and operated by the Mesa Police Department, sustained substantial damage. The certificated private pilot and two passengers received serious injuries. Visual meteorological conditions prevailed. The flight originated at Yuma International Airport, Yuma, Arizona, at 1152 hours. A ground witness said that he heard the engine sound, followed by an abrupt silence. The engine started and stopped twice. He last saw the airplane descending and then disappeared behind the trees. A Federal Aviation Administration (FAA) airworthiness inspector from the Scottsdale, Arizona, Flight Standards District Office conducted the on-site investigation. The inspector reported that the airplane landed hard in an open field and came to rest within a short distance. He said that his examination of the wreckage revealed that the left main fuel tank was empty. The fuel tank was not compromised. The right main fuel tank was full and both wing tip tanks contained about 8 gallons of fuel. The fuel selector was found selected to the left main fuel tank. The inspector supervised an engine run-up examination at Lycon, Inc., Falcon Field, Mesa, Arizona on August 30, 1995. Lycon maintenance personnel replaced the propeller and the carburetor before doing the engine run-up. The engine operated normally during the run-up. The carburetor broke off from its attach points. Disassembly examination of the carburetor, a Facit MA-4-4, serial No. R4410924, revealed no evidence of any preexisting malfunctions or failures. The carburetor bowl and inlet screens were free of contaminates. The pilot told the FAA inspector and other police investigators that he does not recall any of the events preceding the accident. The Mesa Police Department reported that the pilot sustained extensive head injuries.