On September 24, 1994, approximately 1700 Alaska daylight time, a Cessna 170A, N5583C, was destroyed during landing at a private strip near Nikiski, Alaska. The airplane, owned by the commercial pilot, was on a local civil air patrol check flight with an airline transport rated instructor pilot in the right seat. There was a company VFR flight plan in effect and visual meteorological conditions prevailed. Both the check pilot and the commercial pilot/owner received minor injuries. According to information provided by the crew, they departed Kenai, Alaska, at about 1620 on a local area practice flight. After completing the air work, the commercial pilot decided to execute a practice forced landing at a nearby 4,000 foot private strip. He set up on a left downwind at 2,500 feet and cut the power. The check pilot stated that as the airplane turned final it was apparent to the pilot that he was high and he elected to slip the airplane down to about 400 feet AGL. When the pilot terminated the slip, it seemed to the check pilot that his altitude and airspeed were "perfect" for touchdown about 200 feet beyond the threshold. The check pilot then diverted his attention to other things outside the airplane. The pilot stated that on short final he entered a second slip to dissipate excessive airspeed and "landed short of runway." The check pilot said he sensed the second slip and he noticed that the airplane was low. He called for a go around immediately before impact. The airplane impacted an embankment that sloped up to the runway about 25 feet short of the threshold.