Amateur-built ACRO SPORT II N94SM accident near Middletown, Ohio

Probable cause

The failure of the flying pilot to maintain airplane control after an aerodynamic stall/spin occurred during the aerobatic maneuver following a reported intermittent loss of engine power for reasons that could not be determined during postaccident examinations.

NTSB analysis

The pilot and pilot-rated passenger were flying a local flight and performing aerobatic maneuvers in the experimental amateur-built airplane. A witness reported that she heard the airplane approaching and then saw it and noted that it was at a lower altitude than she normally saw aircraft in the area. The airplane then started to pitch nose up into a loop. As the airplane reached the top of the looping maneuver, the sound of the engine stopped, and the airplane then immediately started descending. The airplane then entered a spiral/spin, and the witness lost sight of the airplane behind some trees. She then heard the sound of an engine, consistent with the pilot adding engine power, followed immediately by the sound of impact. The airplane was engulfed in flames upon her arrival. The witness demonstrated what she had seen with a model airplane, and the demonstration was consistent with an attempted loop with a spin out of the top of the maneuver.

Witness marks at the accident site revealed that the airplane was producing power at the time of impact. An examination of the engine and flight controls did not reveal any preimpact anomalies that would have precluded operation. A weight and balance calculation showed that the airplane was within its published limits. The airplane likely experienced an aerodynamic stall at the top of the looping maneuver and then entered a spin from which the flying pilot was not able to recover. The investigation could not determine which occupant was manipulating the controls during the flight.

Text from the NTSB. Open the NTSB docket for CEN14LA507 for the full record.