On February 12, 1999, about 1430 hours Pacific standard time, a Beech 95, N1176, was substantially damaged when it collided with the ground following an inadvertent shutdown of one engine while landing at the Henderson, Nevada, airport. The aircraft was operated by Sheble Aviation, Bullhead City, Arizona, under 14 CFR Part 91. Neither the commercial pilot/certified flight instructor nor the student pilot was injured. Visual meteorological conditions prevailed for the local area dual instructional flight and no flight plan was filed. The flight originated at Mesquite, Nevada, at 1400. A Federal Aviation Administration inspector from the Las Vegas, Nevada, Flight Standards District Office, responded to the accident site and interviewed both the instructor and student. According to their verbal statements, the aircraft was on approach when the student pilot, who was flying, changed fuel tanks. The student pilot inadvertently shutoff fuel to the right engine as he was looking for traffic. While executing S-turns for spacing, the right engine lost power. The inspector reported that there was confusion in the cockpit and the appropriate emergency procedures were not executed. According to the student pilot, after the instructor realized that they had lost power on the right engine the instructor assumed control of the airplane. The student pilot stated that at that point they began going through engine-out procedures while holding "blue line" ( best single engine climb rate of climb speed). He said by the time that they got to the gear-up procedure it was too late, they hit the ground. After they exited the airplane and determined that there was no fire, they went back to the airplane and found the right fuel selector turned to the off position. According to the Beech 95 owner's manual page 64 and 65, Descent and Pre-landing Check should be accomplished prior to entering the traffic pattern. "With these checks out of the way, you will be able to concentrate on traffic pattern problems and final landing preparations." The owner's manual also addresses the importance of following the single engine procedures. Pages 108A, 111, and 113 documents the procedure and emphasizes the importance of reducing all unnecessary drag in as short a time as possible.