NTSB Factual Report

On May 7, 2004, at 1320 Pacific daylight time, a Willis T/Rocket Flyers LLC, N724TL, collided with a tree during a forced landing that was precipitated by a loss of engine power 3 miles northeast of Tipton, California. The airline transport pilot/owner was operating the airplane the under the provisions of 14 CFR Part 91. The pilot and passenger were not injured, and the experimental category airplane sustained substantial damage. Visual meteorological conditions prevailed, and an instrument flight plan had been filed. The personal cross-country flight originated at Eloy, Arizona, about 1120 mountain standard time.

The pilot told the National Transportation Safety Board investigator that the airplane turboprop Diemech M601D engine lost power about 25 miles east of Tulare, California, their destination. About 1,000 feet above ground level (agl), the pilot selected an area to make a forced landing. He identified some power lines that were in the selected landing area so he diverted the airplane to a highway and landed gear up. To avoid a truck, the pilot veered the airplane off the highway and into rough terrain where the wing struck a tree.

A Federal Aviation Administration inspector supervised an airframe and engine examination. He determined that the airplane had fuel in its fuel tank when it landed. He found air in the engine's fuel control system. Maintenance technicians bled the fuel control and fuel pump. They then completed a test run of the engine without incident.

The pilot stated in the Pilot/Operator Accident Report that because air was found in the fuel control unit there was a possible design flaw in the way fuel is delivered from the fuel tank to the engine.

NTSB Probable Cause

A loss of engine power due to fuel starvation as a result of air migrating into the fuel control unit. The ultimate reason for the air entry into the fuel control unit was not determined.