Cessna 210A N6630X accident near Benson, Arizona

Probable cause

A loss of engine power due to fuel starvation as a result of a loss of fuel pressure caused by the fuel pump screws being loose. Contributing to the accident was inadequate maintenance.

NTSB analysis

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.

Text from the NTSB. Open the NTSB docket for WPR10LA251 for the full record.