Amateur-built 235 N25NL accident near Cordes Lakes, Arizona

Probable cause

The pilot’s exceedance of the airplane’s critical angle of attack during an aerobatic maneuver, which resulted in an aerodynamic stall and spin and a loss of control. Contributing to the accident was the pilot’s lack of aerobatic experience in the accident airplane make and model.

NTSB analysis

The pilot was conducting a visual flight rules cross-country flight. Data downloaded from the airplane’s avionics showed that, during cruise flight about 17 minutes after takeoff, the pilot executed a left 360° roll. During the maneuver, the airplane descended more than 1,000 ft, and its vertical acceleration increased from -0.7 to 2.9 G. A few seconds after the completion of the roll maneuver, the engine rpm and oil pressure decreased to zero, and the airplane’s attitude, accelerations, and airspeed parameters became unreliable. A friend of the pilot reported that the pilot had recently learned how to perform rolls in a different make and model of airplane, but no further details were available.

Wreckage and impact signatures were consistent with the airplane impacting terrain in an inverted spin. Postaccident examination of the airplane confirmed continuity to all flight control surfaces, and no engine or airframe anomalies were found that would have precluded normal operation. It is likely that the pilot intentionally attempted an aerobatic maneuver, lost airplane control, and exceeded the airplane’s critical angle of attack, which resulted in a stall, a subsequent spin, and an impact with terrain.

The ethanol identified in the pilot’s cavity blood was most likely the result of postmortem production. Therefore, effects from ethanol did not play a role in this accident.

Text from the NTSB. Open the NTSB docket for WPR21FA025 for the full record.