Collision Overview
A Bellanca 7ECA Citabria and an experimental Thorp T-18 collided in flight during separate local area flights along the southern California shoreline. Both airplanes impacted the ocean in the area of the collision. Day visual meteorological conditions prevailed with no visibility restrictions.
Radar Data
Review of recorded radar data showed the Citabria as a primary target with no Mode C altitude reporting. The Thorp was identified as a secondary 1200 VFR beacon code with Mode C altitude reporting. The Citabria's radar track showed it flying south over coastal hills until it intersected with the shoreline. At the shoreline, the Citabria's target passed in front of the Thorp's radar target and continued southbound until about 0.75 nautical miles offshore. The Citabria then turned left 180 degrees, heading north. The Thorp flew along the coastline until about 8 nautical miles northwest of the accident site, then made a right 180-degree turn and tracked back along the coastline. About 2 nautical miles northwest of the collision point, the Thorp's Mode C reported an altitude of 2,400 feet MSL. Its Mode C altitude continued increasing until the radar track stopped. At that time, separation between the two targets was about 0.5 nautical miles. The Thorp continued eastbound in a slight climb, and the Citabria continued northbound until radar contact with the Thorp was lost at 1729:37 at 2,900 feet MSL. The Citabria was lost at 1730:10. Their tracks were approximately perpendicular in the final minutes.
Wreckage and Examination
Both aircraft impacted the water after the midair collision. The Citabria washed ashore on the beach. The Thorp impacted the water about 150 yards east of the Citabria and sank in about 20 feet of water. Both airplanes were destroyed during the collision and impact sequence with the water, and further damaged by tidal action before and during recovery. All flight control components and control surfaces for the Citabria were accounted for, except the left wing strut, which was white and not recovered. Examination of the Citabria for paint transfer from the Thorp was negative. Examination of the Thorp was inhibited due to post-accident ocean impact and tidal damage. The Thorp's propeller showed white paint transfer marks near the hub extending outward, and one blade tip had a large leading-edge gouge. Examination of the Thorp revealed light blue paint transfers on the underside of the right horizontal stabilizer cap, similar to the Citabria's coloration. Both airplanes were operating in uncontrolled Class G airspace when the collision occurred.