The airplane had just undergone an annual inspection and the pilot was returning to the airport after conducting a post-maintenance flight test. The pilot stated that he made a normal approach to land with both the flaps and landing gear extended. He further described that upon landing, the airplane settled to the runway, and skidded to a stop resulting in substantial damage to the lower fuselage. A postaccident examination of the airplane revealed minor damage to the nose landing gear door and no damage to the main landing gear doors. The landing gear was subsequently cycled several times using both normal and emergency methods. No evidence of any preimpact mechanical malfunctions or failures were noted that would have precluded normal operation of the landing gear system. Based on this information, it is most likely that the pilot landed the airplane with the landing gear still retracted.