Amateur-built RADIAL ROC N91TX accident near Socorro, New Mexico

Probable cause

The pilot's failure to maintain adequate airspeed during the visual approach to the runway, which resulted in an aerodynamic stall. Contributing to the accident were the pilot’s lack of experience in the airplane make and model and the possible sedating effects of medication.

NTSB analysis

The pilot had purchased the airplane the day before the accident and had performed a 30-minute flight with the previous owner. During the purchase inspection, the pilot reportedly expressed concern about the electronic flight display, the autopilot, the mixture control operation, and the boost pump systems. No additional transition training was accomplished in the airplane before the accident flight. Just before the accident, a witness heard abnormal engine sounds (“popping”) and observed the airplane flying erratically in the traffic pattern. While maneuvering toward the airport, the airplane's wings were rocking back and forth, which was consistent with a near stalled condition, before the airplane pitched up then entered a nose-down descent into terrain. The previous owner stated that proper mixture control position and boost pump position was critical during landing, or the engine may stumble or experience a brief shutdown. A postaccident examination of the wreckage did not reveal any evidence of preimpact anomalies. It is likely that the pilot, due to his limited training (30 minutes) in the airplane make and model, was unfamiliar with the unique characteristics of this airplane and its avionics, and that contributed to his failure to maintain airspeed while maneuvering.

In a 2012 safety study on "The Safety of Experimental Amateur-Built Aircraft," the NTSB concluded that "purchasers of used [experimental amateur-built] (E-AB) aircraft face particular challenges in transitioning to the unfamiliar E-AB aircraft. Like builders of new E-AB aircraft, they must learn to manage the unique handling characteristics of their aircraft and learn the systems, structure, and equipment, but without the firsthand knowledge afforded to the builder." Thus, the NTSB recommended that the Federal Aviation Administration and the Experimental Aircraft Association "complete planned action to create a coalition of kit manufacturers, type clubs, and pilot and owner groups and (1) develop transition training resources and (2) identify and apply incentives to encourage both builders of experimental amateur-built aircraft and purchasers of used experimental amateur-built aircraft to complete the training that is developed."

Postmortem toxicology testing for the pilot indicated positive results for ibuprofen, lorazepam and tramadol. The pilot had not reported any medication on his most recent medical application about 10 months before the accident. Although such medications can have sedating and/or impairing effects, it was not possible to determine to what extent the pilot may have been impaired.

Text from the NTSB. Open the NTSB docket for CEN11FA652 for the full record.