20131022020979I

The instructor, - began his day at 0930 CDT teaching a two hour ground lesson to a different student. He then flew an instructional flight at 1130 that lasted approximately 2.2 hours. His second instructional flight was cancelled due to lack of aircraft. He then took the opportunity to eat before the upcoming night flight. He briefed the night flight student, and was dispatched at approximately 1840 CDT. They flew to Alliance Airport in order to conduct 10 night take-offs and landings at a tower controlled field. The traffic pattern was initially set up to land on runway 34, but soon changed due to wind shift to 16. The instructor requested runway 16L in order to help the student see the runway better from the left seat. On the next pass the aircraft landed gear up at approximately 2030 CDT. The instructor confirmed mixture and props were full forward, of the ?gumpss? Checklist, but could not recall if they had put the gear down. He also stated he did not hear the gear horn. The aircraft landed nearly on centerline at the fixed distance markers of 16L and slid to a stop after approximately 1200 feet. No injuries were reported. The FAA iic arrived approximately 2100 and checked the aircraft and runway. The gear handle was in the down position, but the gear appeared to be in the up position. The maintenance crew reported that after lifting the aircraft and the gear came down and locked with 3 green lights.