On July 1, 1999, approximately 1515 mountain daylight time, a Piper PA-18-150, N4785F, owned and operated by the Soaring Society of Boulder, was substantially damaged when the aircraft nosed over during landing roll at Boulder Municipal Airport, Boulder, Colorado. The private pilot, the sole occupant aboard, was not injured. The local glider tow flight was being conducted under Title 14 CFR Part 91, and no flight plan had been filed. The flight originated approximately 15 minutes prior to the accident, and visual meteorological conditions prevailed. According to the pilot, she departed the airport with a glider in tow. After the glider was released, she returned to the airport for landing. The pilot stated that the wind was calm during landing. She made a "smooth wheel landing with no bounces," and the aircraft rolled "straight and smoothly" on the two main wheels (in a telephone interview with the pilot shortly after the accident, she stated that the aircraft's wheels touched down twice on the runway prior to the third actual touchdown.) She felt the tail of the airplane begin to rise, and she pulled back on the stick. She stated that there was no response from the elevator, and the aircraft continued to roll forward slowly until the spinner impacted the pavement. The airplane then nosed over onto its back. The aircraft sustained damage to the propeller, firewall, vertical stabilizer, and both wing spars. At the NTSB's request, a functional test of the elevator control system was performed by a mechanic with Jensen Aircraft, Salida, Colorado. The elevator operated effectively, and no abnormalities or discrepancies were found.