WPR10LA251

The pilot reported that when he initiated a turn to final approach for landing, the engine suddenly lost power. He checked the cockpit gauges and the fuel selector, before attempting an unsuccessful engine restart. Unable to reach the runway, the pilot initiated a forced landing onto a ridge. During the landing, the left main landing gear and nose landing gear separated and the airplane slid to a stop on its nose. During the postaccident examination of the engine, the fuel system was tested and the fuel manifold diaphragm was found to be brittle and stiff. The engine driven fuel pump was fuel stained and when further inspected, the four screws that hold the body of the fuel pump together were found loose. When the pump was submerged in fuel and manually rotated, it emitted fuel along with large air bubbles. The four screws were then tightened and the pump was again submerged in fuel. The fuel flowed normally without any air bubbles present. It is likely that the fuel manifold valve would require more fuel pressure than normal for it to function properly because of the fuel diaphragm’s brittleness and stiffness. It is also likely that the four loose screws on the fuel pump body allowed air to mix in with the fuel causing the pump to cavitate. Therefore, the fuel pressure dropped to a level that would cause the fuel manifold valve to close, subsequently starving the engine of fuel. An annual inspection was reported to have been completed 11.1 hours prior to the accident.

On May 21, 2010, about 1030 mountain standard time, a Cessna 210A, N6630X, lost engine power during approach to landing at Benson Municipal Airport (E95), Benson, Arizona. The airplane subsequently collided with terrain during the off airport landing, substantially damaging the left wing. The pilot was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot and one passenger received minor injuries. The local personal flight departed Benson about 1130. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that he extended the downwind leg of the traffic pattern to test the landing gear warning system before he turned to the base leg. As the pilot initiated a turn to final, the engine suddenly lost power. The pilot scanned all of the gauges and confirmed the fuel selector valve was on the fullest fuel tank; he then turned on the boost pump and attempted to restart the engine, but was unsuccessful. The pilot observed a nearby road and attempted to land on it, however, the airplane landed short onto a ridge. Both the left main landing gear and the nose wheel landing gear were sheared off and the airplane slid on its nose until it came to a rest. Post accident examination of the engine by a certificated airframe and powerplant mechanic and a Federal Aviation Administration inspector reported that the fuel system was tested and the diaphragm in the fuel manifold valve was found to be brittle and stiff. The engine driven fuel pump had fuel stains on it, and when further inspected, the four screws that hold the body of the fuel pump together were found loose. The pump was submerged in fuel and manually rotated with a drill motor at 2,000 rpm; it emitted fuel along with large air bubbles. The four screws were tightened and the pump was again submerged in the fuel; it flowed normally without any air bubbles present. Examination of the airplane records indicated that an annual inspection had been completed on February 1, 2010, with a reported tach time of 4,736.7. The tach time at the time of the accident was 4,747.8.