At about 17:40 EDT, a homebuilt Pitts S-1S crashed near Westtown, killing the pilot. A witness flying with the accident pilot in a separate airplane, said the accident pilot wanted to practice her sportsman aerobatics routine for an upcoming competition. The witness stayed about -mile to the east and watched the accident pilot practice. The accident pilot entered her aerobatics sequence approximately 3,500 feet msl, and completed several maneuvers before entering a spin to the left. After 1 turns the airplanes rotation started to slow, but then accelerated two turns later. About seven turns into the spin, the witness received a radio transmission from the accident pilot in which she said she could not get out of the spin. Approximately 50 feet before impact, the witness noticed that the descent rate and rate of rotation of the airplane had slowed and the nose started to come up. The pilot had been wearing a parachute but had not attempted to bail out.