On August 23, 2009, about 1035 Pacific daylight time, a Piper PA-24-260, N8775P, collided with several automobiles during an emergency landing on a freeway near Santa Barbara, California. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot and one passenger were not injured; the airplane sustained substantial damage to the wings, empennage, and fuselage. The cross-country personal flight departed French Valley Airport, Murietta, California, about 0930, with a planned destination of Santa Barbara. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot stated that he departed French Valley with an estimated 32 gallons (28 useable) of fuel on board for the 148 nautical mile (nm) flight. He thought that the flight would take about 1.1 hours, which would leave a 1-hour fuel reserve. He used the left main tank for takeoff, climb, and initial cruise; he switched to the right main fuel tank near Van Nuys, California. According to his global positioning system (GPS), he had traveled 91 miles from French Valley, and was 57 miles from Santa Barbara. His fuel flow gauge indicated a fuel burn of 12.5 gallons per hour. The pilot reported that he was about 5 miles out on the approach to Santa Barbara when the engine began to run rough and lose power. He turned the fuel boost pump on, and switched back to the left main tank. He was unable to restore full engine power. He declared an emergency, and prepared to make an off airport forced landing. Because of terrain and other considerations, he landed on the southbound 101 freeway. Immediately after touchdown, an automobile struck the left wing, which separated. Two other automobiles struck the airplane before it came to a rest. The pilot noted that during the recovery, there was no evidence of fuel, including the 4 gallons of unuseable fuel. He opined that the fuel vented from the airplane due to a mechanical problem. Airframe examination Investigators from the National Transportation Safety Board, the Federal Aviation Administration, Piper Aircraft Corporation, and Textron Lycoming examined the wreckage at a recovery facility. They observed no fuel stains on the top or bottom surface of either wing. The left wing main fuel tank filler access door was unlatched and open. The thermos style fuel cap was in place, but in the unlatched position. When investigators latched the filler cap, it was loose in the filler hole, and could easily be rotated. The access door for the outboard (auxiliary fuel tank) was closed and latched. The thermos style fuel cap was latched and tight in the filler hole. There were no fuel stains around the main or auxiliary fuel caps. The right wing separated outboard of the flap area. The right main fuel tank access door was unlatched and open. The thermos style fuel cap was not in the filler hole, and not located. The outboard auxiliary fuel tank cap had been removed from the filler hole, and was on the ground near the wing section. When installed and latched in the filler hole, the cap was tight and secure. There were no fuel stains around the main or auxiliary fuel caps. Investigators observed no fuel stains on the bottom fuselage skins. They removed the quick drain fuel strainer assembly located on the belly of the fuselage for examination. The inside of the access panel for the assembly exhibited a dark blue stain around the hole for the quick drain valve hose. There were no stains on the outside of the panel. The quick drain valve was attached to a bowl assembly. The pilot operates the quick drain by pulling a handle under an access door in the floorboard that is aft of the fuel selector valve. The bracket assembly that physically depresses the quick drain valve when the drain handle is pulled is supposed to be positioned on the front side of the quick drain. Investigators discovered that it was on the back side of the valve. In this position, the quick drain valve could not be opened when the drain valve handle was pulled. After investigators disassembled the unit and reinstalled the components in the correct position, the valve functioned properly. Disassembly of the fuel strainer bowl revealed corrosion pitting on its interior. It contained a blue fluid that smelled like aviation gasoline; the fluid contained some sediment and other contaminants. The filter screen had small amounts of contaminants. The rubber seal on the outer edge of the screen appeared weathered. Engine Examination There was no visible fuel retrieved from any of the engine fuel system components during the examination. There was no fuel staining observed at any of the engine compartment fuel system components. Examination of the engine revealed no anomalies that would have precluded normal operation.