At 13:15 central time, a Cessna 172RG was damaged during a precautionary landing near Washington after the pilots encountered smoke in the cockpit. The pilot and the CFI suffered minor injuries. The pilots were practicing commercial flight maneuvers when they smelled an electrical fire. They immediately began to return to the airport, but two minutes later the cockpit filled with smoke. The pilots secured all electrical equipment and landed in a field, where the airplane nosed over. An investigation showed chafing of electrical wires between the engine firewall and cockpit instrument panel. A plastic hydraulic reservoir was found melted and laying on the cockpit floor.