On April 13, 2001, about 2000 Pacific daylight time, a Cessna 172 RG, N9551B, sustained substantial damage during a wheels-up landing at Tacoma Narrows Airport, Gig Harbor, Washington. The airplane is owned by Northwest Zephyr Aviation, and was being flown by the pilot as a personal/pleasure flight under the provisions of Title 14, CFR Part 91, when the accident occurred. The private pilot, the sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the local flight. The flight originated from Tacoma Narrows approximately 30 minutes prior to the accident. During a telephone interview and subsequent written statement to the National Transportation Safety Board, the pilot reported that shortly after takeoff from runway 17, he noted a "high pitched hissing tone" in conjunction with the illumination of the airplane's low-voltage light. He reported that the situation lasted for a few seconds before the hissing tone subsided and the low voltage light returned to normal. The pilot stated that he thought there "might" be a problem with the aircraft's engine and elected to return to the airport and land on runway 35. The pilot turned the airplane 180 degrees and attempted to land on the opposing runway. After completing the turn, the pilot realigned the airplane on the runway centerline. He stated " I thought I did reach over and put the landing gear lever in the down position, but I don't remember for sure." The pilot stated that just before touchdown, he heard what he thought was the sound of the propeller striking the runway. He applied power and initiated a go-around. The pilot stated that he then aborted the go-around and "put the gear down" in an attempt to land the airplane on the remaining runway. The airplane touched down on the runway and the right main landing gear leg collapsed. The airplane made several heading changes before coming to rest in a grassy area northeast of runway 17-35. The airplane's horizontal stabilizer sustained substantial damage. In a written statement, a witness to the accident (a certified pilot) reported that the "...aircraft descended onto the runway without the landing gear [gear retracted] and bounced." The witness reported that after the airplane bounced back into the air, he "...heard [engine] power increase" just before the airplane contacted the runway a second time. A FAA Inspector from the Flight Standards District Office, Seattle, Washington, inspected the airplane after the accident and reported that there was no evidence found to indicate a mechanical failure or malfunction with the airplane prior to the accident.