The flight instructor stated that he was teaching the student pilot a soft-field takeoff technique on a 2,300-ft-long turf runway, with a passenger in the back seat. The flight instructor further stated that the student pilot lifted off the airplane at 52 knots, but it settled back to the runway as the wind shifted from a headwind to a tailwind. The airplane then traveled about 100 ft beyond the departure end of the runway and struck bushes, coming to rest upright. The flight instructor added that there were no preimpact mechanical malfunctions with the airplane. Examination of the wreckage by a Federal Aviation Administration inspector revealed substantial damage to the left wing and fuselage. The inspector noted that the flaps were in the fully retracted position and asked the flight instructor why he did not perform the accident takeoff with 10° flap extension, per the owner’s manual. The flight instructor replied that was always how he performed soft-field takeoffs. The recorded wind speed about the time of the accident was 3 knots.