On April 7, 2003, about 1550 Pacific daylight time, a Deer/Reffalt BD, N4365K, collided with power lines during a forced landing following a loss of engine power near Greenfield, California. Vaquero Aero was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, sustained a minor injury; the airplane sustained substantial damage. The personal local flight departed Metz Field near Greenfield about 1450. Visual meteorological conditions prevailed, and no flight plan had been filed. The primary wreckage was at 36 degrees 20 minutes north latitude and 121 degrees 13.0 minutes west longitude. The pilot stated that he was flying in the local area. As he was returning to the airport, the engine lost power. He applied carburetor heat, and the engine power increased for about 30 seconds. Then another loss of power occurred. This series of power loss and restoration happened three times. The engine did not cough, sputter, or make any metallic sounds. He set up a glide, but was unable to avoid a collision with power lines. The airplane came to rest vertically along side of agricultural shipping containers. The National Transportation Safety Board investigator-in-charge (IIC) examined the airplane and engine at Plain Parts in Pleasant Grove, California, on July 8, 2003. The IIC selected the right main tank on the fuel selector valve. Recovery personnel plumbed a remote fuel tank into the right main tank fuel line. They bled the fuel system, and drained fuel into a clear glass bottle. The IIC observed no solid contaminants or water in the drained fuel. He detected no loose fuel lines, and observed no fuel stains or leaks. He blew into the vent line from the header tank, and uncontaminated fuel exited through the other end of the tube. Recovery personnel secured the wreckage to a trailer. An operator started the engine. The operator ran the engine up to 1,800 revolutions per minute (rpm). He completed a magneto check, and the IIC observed a smooth 50-rpm drop on each magneto. The engine idled at 550 rpm. The operator shut the engine off by pulling the mixture control. The IIC noted that the engine shut down smoothly with a 50-rpm increase. According to FAA Advisory Circular AC 20-27F, Certification and Operation of Amateur-Built Aircraft, "Amateur builders are free to develop their own designs or build from existing designs. We do not approve these designs and it would be impractical to develop design standards for the wide variety of design configurations, created by designers, kit manufacturers, and amateur builders."