Accident Summary
A certified flight instructor (CFI) was conducting a training flight. During the landing approach, the CFI demonstrated a forward slip to lose altitude. The landing rollout proceeded normally until the CFI attempted to slow the airplane by applying light pressure on both heel brakes.
Narrative
As the airplane rolled out, the CFI pressed both heel brakes lightly. The airplane began to yaw to the right. In response, the CFI applied additional pressure on the left brake, but there was no discernible response. The airplane continued to veer right, departed the runway surface, and ground looped. No further control inputs or actions were described as effective in preventing the ground loop.
Post-Accident Examination
A Federal Aviation Administration (FAA) inspector examined the airplane's brake system following the accident. When the inspector depressed the brakes, he reported that they felt "a little spongy" but were completely operational. The examination did not reveal any definite mechanical failure or blockage.
No probable cause was determined from the available information.