The pilot stated that he last checked the fuel quantity before a flight that he conducted 2 weeks prior to the accident flight. During that flight, he noticed that the right auxiliary fuel gauge was inoperative. The airplane landed uneventfully and remained in a hangar until the accident flight. The purpose of the accident flight was to drain fuel from the right auxiliary fuel tank, in order for maintenance work to be performed on the fuel tank sending unit. The pilot did not check the fuel quantity prior to the accident flight as he estimated that sufficient fuel remained from the previous flight. The pilot completed a 20-minute local flight and was on final approach to land, with the fuel selector positioned to the right auxiliary fuel tank, when a low fuel pressure indicator light illuminated in the cockpit. At that time, the airplane was about 800 feet above ground level, over a populated town. The pilot activated the fuel boost pump, but did not reposition the fuel selector to a different fuel tank. The engine subsequently experienced a total loss of power and the pilot performed a forced landing into trees and a river. During the landing, the airplane sustained substantial damage to both wings and the fuselage. The pilot further stated that the accident was "pilot error" as he ran the right auxiliary fuel tank dry.