On May 27, 1994, at 1345 Pacific daylight time, a Cessna 150M, N63105, struck the left wing tip on a berm following an in-flight loss of control near Lancaster, California. The aircraft was owned and operated by Professional Pilot Training of Burbank, California, and was engaged in local area dual primary flight training. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft sustained substantial internal damage to the left wing ribs and stringers. Neither the certificated commercial pilot flight instructor nor his dual primary student were injured. The flight originated at Burbank, California, on the day of the accident at 1230 as a dual instructional flight. The accident was reported to the National Transportation Safety Board on June 6, 1994, following assessment by company maintenance personnel of the damage extent. In a telephone interview, the pilot said the purpose of the flight was to practice ground reference maneuvers. After departure from Burbank, the flight proceeded to a desert area near Lancaster where the maneuvers could be accomplished in an unpopulated area. The instructor said that after the maneuvers were finished, the student began a climb to cross a mountain range between Lancaster and Burbank. About 4,100 feet msl (1,300 agl), the instructor asked the student to demonstrate minimum controllable airspeed. The student complied and configured the aircraft with full flaps and slowed to the minimum airspeed with the stall warning horn on steady. The instructor reported that the aircraft began to deviate in heading and he applied full power and right rudder. The aircraft suddenly stalled and rolled completely around the longitudinal axis, then began an uncontrolled descent toward the ground. The instructor said he was able to recover at an estimated 3 to 4 feet above ground level and the left wing tip hit a berm. The instructor climbed the aircraft back to cruise altitude and continued the flight back to Burbank.