WPR24FA213

An aerodynamic stall and loss of control for reasons that could not be determined based on the available information.

Before the accident pilot departed on his first solo flight in the single-seat, turbopropeller-equipped biplane, the chief pilot instructed him to depart to the north, climb to altitude, practice turns, climbs and descents, and then return to the departure airport. The chief pilot and the accident pilot were unable to communicate via radio and instead exchanged several text messages during the flight. The accident pilot sent a message stating, “it shakes a little bit, I don’t know if its normal,” to which the chief pilot replied, “Yeah it’s just a lot of horsepower on the front of the plane.” There were no further communications from the accident pilot. Shortly thereafter, the chief pilot observed smoke rising from the area where the pilot was operating. He departed in another airplane and subsequently located the accident site. Two witnesses saw the airplane flying low from north to south. Both witnesses reported that the engine sounded normal. One witness stated that he saw the airplane’s wings rocking left and right several times. The airplane came to rest in sandy desert terrain and was largely consumed by a postimpact fire. No ground scars were observed near the accident site. All major components of the airplane were present, and impact damage was consistent with a right-wing-low, nose-down pitch attitude at the time of impact. Control continuity was established for the left and right lower wing flaperons from the cockpit to the control surfaces. Rudder control continuity was established from the cockpit to the rudder. Elevator control continuity could not be confirmed due to impact and thermal damage. Postaccident examination of the propeller revealed operational signatures consistent with low-to-moderate engine power. Postaccident examination of the engine revealed evidence consistent with the engine producing power at the time of impact, with no indications of preimpact mechanical malfunctions or failures that would have precluded normal operation. Review of the airplane’s maintenance records indicated that its most recent annual inspection was 13 months before the accident. The airplane was issued a special flight permit 20 days before the accident that was valid for 10 days and allowed the airplane to be ferried for repairs or maintenance. The chief pilot reported that the accident flight was the airplane’s first flight following maintenance and that the mechanic had not completed a logbook entry. The mechanic who performed the maintenance stated that she had started the airplane’s annual inspection but did not complete it, because the owner wanted to fly the airplane. When asked, the chief pilot stated that he made the decision to fly the airplane. Review of records provided by the operator after the accident revealed a new entry for an annual inspection, dated the day of the accident. Review of the pilot’s logbook indicated that, in the months before the accident, he received agricultural application training in several models of tailwheel-equipped airplanes, including a high performance, piston-engine-powered biplane; however, other than referring to “chair flights” performed before the accident flight, the operator did not provide additional information regarding the pilot’s transition training for the turbine-powered accident airplane. The orientation of the airplane at the accident site and the lack of ground scarring around the wreckage was consistent with the nose-low, near-vertical descent characteristic of an aerodynamic stall; however, the reason for the loss of control could not be determined based on the available information. Although examination of the wreckage did not reveal any mechanical malfunctions or anomalies, the scope of the examination was limited due to the thermal damage sustained during the postcrash fire. Given the pilot’s unfamiliarity with the accident airplane, it is possible that attempting to communicate with the chief pilot via text message during the flight provided an additional distraction that may have contributed to the loss of control.

A review of the pilot’s logbook provided by the operator showed the pilot’s flight experience from beginning March 14, 2024, through June 9, 2024. The pilot’s logbook did not indicate flight experience in the accident airplane make and model, nor did it show flight experience in any other turboprop- powered airplane. The pilot had received a tailwheel endorsement on August 30, 2022, and a high-performance airplane endorsement on April 3, 2024. The pilot’s logbook indicated that he had been undergoing agricultural application flight training in the months before the accident, and that he had flown three different models of tailwheel-equipped airplanes during that time, including a high-performance, piston-engine-powered biplane. According to the operator, the airplane was not conducting an aerial application flight and the hopper was empty. Photos of the airframe maintenance logs taken the day after the accident indicated that the most recent annual inspection was completed May 17, 2023; however, a subsequent review of the logbooks provided by the operator showed an entry for an annual inspection dated the day of the accident. Review of engine maintenance records indicated that the engine was removed and disassembled to replace a leaking compressor seal in January 2023. The engine was subsequently reinstalled on the airplane in May 2023, at which time the propeller flight idle blade angle was set and the propeller was serviced with grease. A ground run/functional check was performed and all parameters were normal and within limits; no leaks were noted at the time. A special flight permit was issued by the Federal Aviation Administration on June 5, 2024, as a ferry flight for repairs, alterations, maintenance, or storage of the airplane to be completed by June 15, 2024. The mechanic who performed the most recent maintenance on the airplane stated that she had started the airplane’s annual inspection. She produced a list of maintenance items that were performed but stated that she had not finished the annual inspection and the owner wanted to fly the airplane. The mechanic stated that she did not have the official engine manufacturer maintenance manual to reference while performing maintenance. The chief pilot stated that the accident flight was the airplane’s first flight since maintenance was performed. There was no post-maintenance test slight. He stated that the mechanic had not signed off the maintenance. When asked why he decided to fly the airplane when the annual inspection had not been completed, the chief pilot stated that the airplane had been “looked over” and that no issues were identified. He also stated that it was his decision, and that the airplane had been flown to the departure airport on a special flight permit. When asked if he could think of any reason that the airplane would shake abnormally, the chief pilot recalled that he and the pilot performed “chair flights” in which he “constantly reminded” the pilot not to decrease the engine torque setting below 15 psi, because the engine would produce a higher pitch winding, a slight vibration would ensue, and the nose of the airplane would pitch down as a result of the decreased airflow over the horizontal stabilizer and elevator. An autopsy of the pilot was performed by the New Mexico – State Office of the Medical Investigator. According to the autopsy report, the cause of death was thermal injuries and inhalation of products of combustion and blunt trauma. Toxicology testing performed at the FAA Forensic Sciences Laboratory found no drugs of abuse. On June 25, 2024, about 1315 mountain daylight time, a Grumman Aircraft Engineering Corporation-Schweizer G-164A, N9709, was destroyed when it was involved in an accident near Chamberino, New Mexico. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 business flight. According to the owner and chief pilot of the agricultural application company, the accident flight was the pilot’s first flight in the accident airplane make and model, and was also the airplane’s first flight since maintenance had been performed. The purpose of the flight was for the pilot to gain flight experience in a turbine-powered agricultural airplane. The chief pilot stated that he instructed the accident pilot to take off to the north, climb “a couple thousand feet” and practice turns, climbs and descents, then return to the departure airport. The chief pilot and the accident pilot had difficulty communicating via radio. The chief pilot sent the accident pilot a text message asking if he could hear him, and the accident pilot indicated that he could barely hear radio transmissions. The chief pilot replied, “ok text me when you head back” and “you may have to talk directly into the handheld.” The accident pilot acknowledged. The chief pilot subsequently received a message that stated, “It shakes a little bit, I don’t know if its normal” to which he replied, “Yeah it’s just a lot of horsepower on the front of the plane.” Shortly thereafter, the chief pilot saw a plume of smoke near the area where the pilot was operating. He subsequently boarded an airplane, flew toward the plume of smoke, and located the wreckage. A witness reported that he saw the airplane flying about 600 ft above ground level about 15 miles west of the departure airport. The witness, who was a former pilot and a long-time resident of the area who was accustomed to seeing agricultural application airplanes, remarked that the airplane’s engine sounded normal and did not sound “bogged down.” Another resident of the area reported that, while riding all-terrain vehicles near the mesa with friends, he saw the airplane fly over the area from north to south, three or four times. He estimated the airplane’s altitude to be 300 ft to 400 ft agl and stated that the engine sounded normal. He reported that the airplane rocked its wings left to right several times, “kind of like it was acknowledging instructions or as if a friend was flying by and rocked their wings from left to right as to say hello.” The airplane impacted a sand berm in desert terrain and came to rest in a right-wing-low, nose-down pitch attitude on a heading of about 020° magnetic. The debris field perimeter was marked by the left lower wingtip, located about 50 ft west of the main wreckage, and the left wing lift strut located about 40 ft south of the main wreckage. No visible ground scars were observed at the accident site. The empennage sustained thermal damage with the primary structure present. The fuselage, cockpit, and inboard sections of the upper and lower right and left wings were mostly consumed by fire. The outboard portions of the upper and lower left and right wings were present and sustained impact damage. The left and right upper and lower wings and flaperons were present and sustained impact and thermal damage. Control continuity was established for the left and right lower wing flaperons from the cockpit to the control surfaces. Rudder control continuity was established from the cockpit to the rudder. Elevator control continuity could not be confirmed due to impact and thermal damage. The propeller hub remained attached to the engine, and two of the three blades were liberated from the hub. Each of the propeller blades showed bending and twisting opposite the direction of rotation. Counterweight impressions in the spinner dome were present and indicative of an operational blade angle (not beta). The link arms were stretched slightly, not bent in compression, and consistent with positive thrust. Examination of the engine revealed rotational scoring on the compressor housing, circumferential rotational scoring and second stage compressor impeller blade deformation, and localized soot deposits on the combustion chamber dome, consistent with rotation and power production at the time of imp