On May 3, 2023, about 1835 Pacific daylight time, a Cessna 210M, N777CF, was substantially damaged when it was involved in an accident near Pasco, Washington. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal fight. The pilot reported that he departed the Richland Airport (RLD), Richland, Washington, and was destined for the Tri-Cities Airport (PSC), Pasco, Washington--the airplane’s home airport. While on the base leg for runway 21L, at about 85 knots airspeed, the engine lost total power. The pilot initiated an emergency landing to an off-airport site and, during the rollout, the airplane contacted road signs, which substantially damaged the left and right wings and the right horizontal stabilizer. The pilot reported that the airplane had just undergone an annual inspection and that there were about 66 gallons of fuel in the wing tanks for the 10-mile flight. Data recovered from the engine data monitor (EDM) revealed engine performance parameters for the 30-minute accident flight. The data revealed consistent operation for the engine throughout the takeoff, climb, enroute-cruise, and descent phases of flight. During the last minute of the flight, all cylinder head temperatures, all exhaust gas temperatures and the fuel flow and fuel psi reduced in value consistent with a total loss of power. The engine was examined and prepared for a test run. Attempts to test run the engine resulted in the engine running for about 2 to 3 seconds before losing power; fuel was observed puddling under the airplane. Further examination revealed the fuel servo outlet line was loosely attached to the fuel servo fitting as shown in Figure 1. No additional anomalies were noted with the airframe or engine that would have precluded normal operation. Figure 1. Photo showing the fuel line off the fuel fitting of the fuel servo. A review of the maintenance logbooks for the airplane revealed that the airplane had undergone a 100-hour inspection that was signed off by the shop’s airframe and powerplant mechanic. The airplane also underwent an annual inspection that was signed off by a shop employee with inspection authorization. According to the mechanic who performed the 100-hour inspection, while working on the airplane, he mistakenly installed the battery leads on the wrong battery posts. This action resulted in a need for additional maintenance over and above the 100-hour and the annual inspections. This additional maintenance included removing and replacing the alternator, and voltage regulator, in addition to removing and repairing the Garmin GTN750, and the transponder. According to the Director of Maintenance, the maintenance shop used online digital maintenance manuals for all the maintenance performed on the airplane and that he could see no reason the fuel line would have been disturbed when removing or reinstalling the alternator. A review of the Cessna Maintenance Manual instructions for removal of the alternator did not direct removal of the fuel servo outlet line. Maintenance records did not show maintenance performed on the fuel servo or fuel outlet line, going back as far as the installation of the rebuilt engine around November 8, 2016.