On June 13, 1993, at 0845 Pacific daylight time, a Cessna 152, N6457L, collided with the runway during a practice go around while performing traffic pattern operations at the Tracy, California, airport. The aircraft was owned and operated by Affordable Aviation of Pleasanton, California, and was rented by the pilot for a local area dual instructional flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft incurred substantial damage. Neither the certificated commercial pilot flight instructor nor the non certificated dual primary student were injured. The flight originated at the Livermore, California, airport on the day of the mishap at about 0730 hours as a local area dual instructional flight. During a telephone interview on June 18, 1993, the flight instructor declined to make a verbal statement. The operator and ground based witnesses to the accident reported in interviews that the instructor and student were practicing touch and go operations on runway 7 at the Tracy airport. During the accident sequence approach to the runway, the instructor had the student initiate a go around. The ground witnesses reported that the aircraft pitched nose up as the power was applied, then the flaps began to retract. The witnesses said the aircraft nose rose higher and the aircraft apparently stalled, then crashed on the runway nose first. In her written statement, the instructor said that as the go around was initiated she added full power and began retracting the flaps "not knowing the student would pull up on the controls." The instructor reported that as the flaps retracted past 30 degrees of extension the aircraft stalled with no warning.