Amateur-built GLASAIR III SH-3R N2XZ accident near Lake Mathews, California

Probable cause

The pilot’s failure to maintain clearance from terrain while maneuvering at low altitude beneath a cloud layer.

NTSB analysis

Review of recorded radar data found a flight track that was consistent with the airplane's high performance capabilities, with its departure point, and ultimately with the accident site. The radar data indicated that a few seconds after the airplane passed over the runway's end, it turned toward the southeast, accelerated to about 190 knots ground speed, and proceeded directly toward the accident site area around a lake. No mode C altitude data was transmitted by the transponder. Upon arrival over the lake, the airplane made two counterclockwise oval-shaped 360-degree turns, with the steepest bank performed as the airplane approached the lake's eastern shoreline. The last radar return was located over the lake's eastern shoreline and within 250 feet of the wreckage location. Based on weather reports from an airport 7 miles northeast of the accident site, an overcast or broken cloud layer at 2,500 feet above ground level likely existed over the accident site. Based on an examination of the crater and airplane wreckage, the airplane impacted the ground at a high airspeed while descending in a slight bank and with the airplane's longitudinal axis pitched downward (nose low) between 55 and 70 degrees. The impact signatures could be consistent with the pilot attempting either a loop or split "S"-type maneuver at an altitude insufficient to recover. There were no witness reports and postaccident examination of the wreckage did not reveal any evidence of a preimpact mechanical malfunction or failure of any airframe or engine component or system.

Text from the NTSB. Open the NTSB docket for WPR11FA027 for the full record.