On July 24, 1998, approximately 1315 Pacific daylight time, a Pilgrim Steen Skybolt, N21SP, was substantially damaged when it collided with terrain when the pilot was unable to maintain control during climbout shortly after takeoff from Chehalis, Washington, for a practice aerobatic flight in the local area. The commercial pilot, the sole occupant, had minor injuries. Visual meteorological conditions prevailed at the time of the accident. There was no report of an ELT actuating. The pilot, who owned the airplane and was an experienced aerobatic pilot, stated that he had taken off, accelerated along the runway, then pitched up to about 30 degrees and had climbed out to about 500 feet above ground level. He then pitched over to level to accelerate and initiated a turn to the right, with the intent of climbing out to an aerobatic practice box. He stated that when he pitched over, he felt negative "G" loading, and the airplane appeared to perform a portion of an outside snap roll, with the right wing dropping and nose going down violently. The airplane then pointed down very steeply about 90 degrees off heading to the right. He stated that an attempt was made to pull out, but the airplane was in a high speed stalled condition, so he pushed the throttle full open and pushed the nose straight down to relieve the stalled condition and again attempted a recovery. This time, the airplane was not stalled and he was able to initiate a pull out. During the recovery attempt, the airplane impacted a road, slightly tail low, and the propeller struck the ground, leaving several prop strikes in the asphalt. The airplane bounced off the road at a 45 degree angle, then impacted a power pole. The pilot noted that the G meter was pegged at +13 G and -5 G. No preexisting mechanical anomalies that could have resulted in loss of control were found by FAA inspectors who inspected the wreckage.