On April 13, 2016, about 1105 Pacific daylight time, a Cessna 421C airplane, N21SG, was substantially damaged during a runway excursion while landing at Furnace Creek Airport (L06), Death Valley National Park, California. The airline transport pilot and two passengers were not injured. The airplane was privately owned and was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed, and no flight plan was filed for the flight, which originated from St. George Regional Airport (SGU), St. George, Utah, about 0945. The pilot stated that the flight was uneventful and that he entered the airport traffic pattern to land on runway 33 at L06. He stated that the airplane touched down within the first 500 ft of runway, and that upon application of brakes, he found the right brake "very soft" and "totally ineffective." The airplane departed the end of the 3,065-foot-long runway and the nose landing gear collapsed, resulting in substantial damage to the fuselage. The airplane was not examined following the accident and was subsequently ferried from L06 to another airport for repair. No information was made available regarding the right brake, and the reason for the malfunction during landing could not be determined. The pilot did not submit the National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident report form 6120.1.