On December 23, 1999, at 1214 hours Pacific standard time, a Pitts S-2B biplane, N87WA, collided with a Piper PA-28R-201, N43793, while taxiing for takeoff from a tee hangar area at the Santa Ana, California, airport. The Piper PA-28R-201 was holding short of a taxiway at the hold line when the collision occurred. The Pitts S-2B, operated by the pilot, sustained minor damage. The Piper, owned and operated by the pilot, sustained substantial damage. Neither private pilot in the Pitts S-2B nor the airline transport pilot in the Piper PA-28R was injured. The local area personal flights were being operated under the provisions of 14 CFR Part 91. Visual meteorological conditions prevailed and no flight plans were filed. A Federal Aviation Administration inspector from the Long Beach, California, Flight Standards District Office responded to the scene and interviewed the pilots. The Pitts pilot stated that he was between a tee hangar row when he had been cleared for takeoff. He said he was performing S-turns for forward visibility while taxiing. During the second S-turn, he contacted the left wing and fuselage of the Piper, causing substantial damage. The Piper pilot stated that he was at the end of the alley between the tee hangar rows holding short of an active taxiway awaiting a clearance from ground control, and did not see the Pitts until the collision. A ground witness was standing on the ramp at the end of a tee hangar row off the right wing of the Piper. He stated that the Piper was stationary and the Pitts taxied up from behind and tried to cut between the Piper and a tee hangar. The witness said he had to run from his location out of the path of the Pitts to keep from being hit. The Pitts pilot failed to sign for a registered letter from the Safety Board requesting the filing of a NTSB form 6120.1/2, Pilot/Operator Aircraft Accident Report.