Accident Overview
On August 23, 2009, at approximately 1035 Pacific daylight time, a Piper PA-24-260, registration N8775P, collided with several automobiles during an emergency landing on the southbound 101 freeway near Santa Barbara, California. The pilot, who was also the owner, was operating the airplane under 14 Code of Federal Regulations Part 91. The private pilot and one passenger were not injured. The airplane sustained substantial damage to the wings, empennage, and fuselage.
Flight Details
The cross-country personal flight departed French Valley Airport in Murietta, California, around 0930, with a planned destination of Santa Barbara. Visual meteorological conditions prevailed, and no flight plan was filed. The pilot estimated that he departed with 32 gallons of fuel (28 usable) for the 148-nautical-mile flight. He anticipated a flight time of approximately 1.1 hours, leaving a 1-hour fuel reserve. The pilot used the left main tank for takeoff, climb, and initial cruise, then switched to the right main fuel tank near Van Nuys, California. According to his GPS, he had traveled 91 miles from French Valley and was 57 miles from Santa Barbara. His fuel flow gauge indicated a burn rate of 12.5 gallons per hour.
Engine Power Loss and Emergency Landing
Approximately 5 miles out on the approach to Santa Barbara, the engine began to run rough and lose power. The pilot activated the fuel boost pump and switched back to the left main tank but could not restore full engine power. He declared an emergency and prepared for an off-airport forced landing. Due to terrain considerations, he landed on the freeway. Immediately after touchdown, an automobile struck the left wing, causing it to separate. Two other automobiles struck the airplane before it came to a stop.
Post-Accident Observations
The pilot noted that during recovery, there was no evidence of fuel, including the 4 gallons of unusable fuel. He speculated that the fuel vented from the airplane due to a mechanical problem.
Airframe Examination
Investigators from the National Transportation Safety Board, Federal Aviation Administration, Piper Aircraft Corporation, and Textron Lycoming examined the wreckage at a recovery facility. No fuel stains were observed on the top or bottom surfaces 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 unlatched. When latched, the filler cap was loose in the filler hole and could be easily rotated. The auxiliary fuel tank access door was closed and latched, with the cap latched and tight. No fuel stains were present around the 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 missing. The auxiliary fuel tank cap had been removed from the filler hole and was found on the ground nearby. When installed and latched, the cap was tight and secure. No fuel stains were observed around the caps.
Investigators observed no fuel stains on the bottom fuselage skins. The quick drain fuel strainer assembly, located on the belly of the fuselage, was removed for examination. The inside of the access panel exhibited a dark blue stain around the hole for the quick drain valve hose, but no stains were on the outside.
The quick drain valve, attached to a bowl assembly, is operated by a handle under an access door in the floorboard aft of the fuel selector valve. The bracket that depresses the valve when the handle is pulled was found positioned on the back side of the valve instead of the front. In this position, the valve could not be opened. After investigators disassembled and reinstalled the components correctly, the valve functioned properly.
Disassembly of the fuel strainer bowl revealed corrosion pitting on its interior. The bowl contained a blue fluid that smelled like aviation gasoline, with some sediment and contaminants. The filter screen had small amounts of contaminants, and the rubber seal on the outer edge appeared weathered.
Engine Examination
No visible fuel was retrieved from any engine fuel system components during the examination. No fuel staining was observed at engine compartment fuel system components. Examination of the engine revealed no anomalies that would have precluded normal operation.