On March 16, 1994, at 0845 hours Pacific standard time (PST), a Piper PA-24-250, N7541P, experienced a total loss of engine power and collided with a tree about one-quarter mile east of runway 28 at Selma Airport, Selma, California. The pilot was conducting a visual flight rules business flight to Fresno Air Terminal, Fresno, California. The airplane, registered to and operated by Producers Livestock Market Association, Yuma, Arizona, sustained substantial damage. The certificated commercial pilot/certified flight instructor and the passenger received minor injuries. Visual meteorological conditions prevailed. The flight originated at Yuma, Arizona, at 0615 hours PST. The pilot submitted a Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2, to the National Transportation Safety Board. In the report, the pilot indicated that the engine sustained a total loss of power at cruise flight at 8,500 feet mean sea level. He immediately began the emergency checklist that included switching the fuel tank selector valve to various positions, but without success. The pilot was unable to restart the engine. During the approach, the pilot observed a "...large lone tree standing almost on the extended centerline of the runway." Realizing that the airplane's altitude was insufficient to make the runway, the pilot elected to strike the tree in a nose-up attitude. The pilot also indicated in the report that he occupied the right front seat. Mr. Gene Sweet, Principal Airworthiness Inspector, Federal Aviation Administration (FAA), Fresno [California] Flight Standards District Office, conducted the on-scene investigation on March 16, 1994. Inspector Sweet reported that an aircraft mechanic said the airplane sustained a total loss of power. After responding to the accident, the mechanic assisted in the removal of the aircraft. Before removing the airplane, the mechanic observed that the fuel selector valve handle was set to the right auxiliary tank. The mechanic repositioned the selector valve handle to the off position and reported that the auxiliary fuel tank was empty. Inspector Sweet said that he found no fuel in the carburetor. The registered owner's insurance adjuster told the Safety Board investigator in a telephone interview conducted on April 22, 1994, that the engine operated normally during the postaccident engine run-up. He also said the passenger told a mechanic conducting the engine run-up that the pilot did change the fuel selector position, but during this time he never reached across him. According to the insurance adjuster, the boost pump switch is located on the left lower side of the instrument panel. The Piper PA-24-250 Owner's Handbook, page 32, states, in part: "The most common cause of engine failure is mismanagement or malfunction of the fuel system...." It then states that "...If changing to the opposite fuel tank does not restore the engine (1) Check fuel pressure and turn on electric fuel pump, if off..."