Aviation Accident Summaries

Aviation Accident Summary WPR21FA025

Cordes Lakes, AZ, USA

Aircraft #1

N25NL

LANCAIR 235

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.

Factual Information

HISTORY OF FLIGHTOn October 24, 2020, about 1028 mountain standard time, a Lancair 235 airplane, N25NL, was substantially damaged when it was involved in an accident near Cordes Lakes, Arizona. The pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. Friends of the pilot reported that he had departed Deer Valley Airport (DVT), Phoenix, Arizona, on the day of the accident with an intended destination of Page, Arizona. On the morning of October 26, 2020, Lockheed Martin Flight Service Station was notified that the pilot had not returned to DVT on October 25. The Federal Aviation Administration issued an alert notice. The wreckage of the airplane was located by law enforcement later on October 26. No witnesses to the accident sequence were identified. The airplane was equipped with a Dynon Skyview D700 electronic flight information system and engine monitoring system. Data downloaded from the units showed the flight departed DVT about 1011 and that, about 4 minutes later, the airplane turned to a northerly heading. The airplane was in a climb until about 1023 when it reached a peak altitude of 8,000 ft above mean sea level (msl). The airplane’s indicated airspeed increased from about 130 to 150 knots while ascending. The data showed that, at 1028:38, the airplane executed a left 360° roll at an altitude of about 7,700 ft msl (see figure 1). During the maneuver, the airplane descended to about 6,500 ft, and its vertical acceleration increased from -0.7 to 2.9 G; at that time, the airplane was about 0.6 miles southwest of the accident site. After 1028:50, 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 (see figure 2). Figure 1. Data showing the end of the flight with selected times and altitudes (in ft msl) noted. Figure 2. Altitude (in ft msl), roll, and engine parameters at the end of the flight. PERSONNEL INFORMATIONA friend of the pilot reported that the pilot had recently learned how to perform rolls in a different type of airplane. The pilot’s friend did not specify the airplane make and model or the date that the training was accomplished. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed that the airplane impacted mountainous terrain on a magnetic heading of about 045° and at an elevation of about 3,720 ft msl. The airplane came to rest inverted except for the empennage, which came to rest upright. All major structural components remained attached to the airframe. Various debris from the airplane was located within 15 ft of the forward area of the airplane. Examination of the recovered wreckage revealed that the fuselage had fragmented into multiple sections. The fuselage structure immediately forward of the empennage was mostly accounted for during the wreckage examination except for two small portions (about 2 to 3 inches by 2 to 3 inches), which were found immediately adjacent to the empennage. The empennage was mostly intact and undamaged. The vertical stabilizer was undamaged. The rudder remained attached via its mounts and exhibited slight impact damage to its bottom. Rudder control continuity was established from the rudder pedals to the rudder. All four rudder cables had separated in various locations. Elevator flight control continuity was established from the cockpit controls to the elevator. The elevator torque tube exhibited an upward fracture about 20 inches forward of the rod end bearing. An additional right bend was observed about 14 inches forward of the fracture separation. Aileron flight control continuity was established from the cockpit controls to the left and right ailerons. The left and right flap torque tubes were intact. Examination of the recovered parts from the engine and airframe revealed no evidence of a preexisting mechanical malfunction that would have precluded normal operation. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the pilot was performed by the Yavapai County Medical Examiner, Prescott Valley, Arizona. His cause of death was multiple injuries. The Federal Aviation Administration Forensic Sciences Laboratory performed toxicological testing on specimens from the pilot. No drugs were detected. Ethanol was detected in the pilot’s cavity blood but not in his urine. N-Butanol was also detected in the pilot’s cavity blood.

Probable Cause and Findings

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.

 

Source: NTSB Aviation Accident Database

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