On March 6, 1995, at 1846 central standard time, a Cessna T210N, N6622N, operated by Prompt Air Inc., of Chicago, Illinois, sustained substantial damage following a loss of electrical power and subsequent emergency landing at Greater Rockford Airport, Rockford, Illinois. The commercial pilot reported no injuries. The 14 CFR Part 135 cargo flight originated in Rockford, Illinois, at 1742 with an intended destination of Midway Airport, Chicago, Illinois. An IFR flight plan was filed and instrument meteorological conditions prevailed at the time. In a detailed written statement, the pilot reported that while the airplane was climbing through solid instrument meteorological conditions (IMC), shortly after taking off from Rockford, the cabin lights flickered and the yoke light came on. Within a short period of time, the low voltage warning light illuminated and the voltmeter indicated an abnormal voltage reading. At this time, the pilot stated that he reported the situation to air traffic control (ATC) and requested the ILS approach to runway 10 at DuPage County Airport for landing. ATC cleared the pilot for the approach, gave him vectors, and also authorized him to turn the airplane's transponder off in an effort to help him conserve power. The pilot then turned off all other unnecessary electrical equipment. While established on the approach inside the outer marker, the pilot attempted to extend the landing gear normally with electrical power in preparation for landing. This procedure used all remaining electrical power of the battery and the airplane's localizer and glideslope indicator flags appeared. The pilot executed an immediate missed approach. It is not known whether or not the landing gear had gone into the down and locked position at this time. Familiar with the area, the pilot stated that after the missed approach he had decided to fly in a westerly direction in an effort to avoid obstructions and congested areas. The pilot stated that he was able to fly back to Rockford by use of dead reckoning. Once he reached the Greater Rockford Airport, the pilot received light gun signals from the tower to land. The pilot stated he followed the emergency gear extension procedure. After landing, the left main landing gear collapsed. The airplane skidded and struck a mound of dirt and a concrete electrical vault before coming to rest. The pilot had stated to the FAA that he was not able to verify that the landing gear was down and locked due to his heavy workload and the ice accumulation on the airplane. Postaccident examination revealed the alternator belt had become unattached. The alternator belt was not cracked, brittle, or glazed, but did have several areas on it which resembled rubbing marks. The airplane log book showed the last inspection was a 50 hour inspection performed on March 3, 1995. The airplane had logged 11.4 hours since the inspection. The airplane's last annual inspection was on May 5, 1994. Review of the Pilot Operator's Handbook for the Cessna T210N, found no mention of a recommended manual gear extension procedure in the event of an electrical system failure or a low voltage situation. The airplane manufacturer is now in the process of incorporating a recommended procedure for manual extension of the landing gear which would help the pilot conserve electrical power for essential navigation and communication equipment.