WPR21FA283

The pilot’s failure to remove the flight control lock before departure, which resulted in a loss of airplane control and impact with terrain. Contributing to the accident was his failure to perform an adequate preflight inspection and flight control check before takeoff.

The pilot was attempting an intersection takeoff about midfield when, shortly after the airplane became airborne, it pitched up aggressively, rolled left, and descended into the ground in a nose-down attitude. Examination did not reveal any evidence of preaccident malfunctions or failures of the flight control system, and there was no evidence to indicate that the pilot’s seat had moved. Both the engine and propeller exhibited damage signatures consistent with high engine power at impact. The airplane was equipped with a flight control locking system that comprised a pivoting, U-shaped control lock tube mounted permanently to the rudder pedal assembly and a forward-facing locking arm mounted to the pilot’s control stick. The control lock immobilized the aileron and elevator controls but still allowed for near-full movement of the rudder and tailwheel. The cabin floor, where the control lock tube should have been mounted for flight, was severely deformed and compressed. Had the lock been stowed during impact, it would have been pinned under the flight control stick, crushed longitudinally, and its retaining clip would have been deformed; however, the control lock and its retaining clip were essentially undamaged, and the lock was found raised off the floor. The locking arm on the control stick also showed no evidence of deformation or impact damage but had rotated about 90° to the right of its normal position, as if forced into that position on impact while the control lock was still attached. Given this information, it is likely that the control lock was installed on the flight control stick during takeoff and impact. High-resolution security camera footage of the accident revealed no discernable movement of the elevators or ailerons, further suggesting that the flight controls were immobilized by the control lock. Although the control lock is painted red, its orientation when engaged results in the pilot viewing it directly down its length, at its narrowest profile. A pilot who owned a similar airplane stated that he had once become distracted during preflight checks and was able to taxi, initiate takeoff, and become airborne with the control lock engaged. He stated that, once he realized his mistake, removal of the lock was a struggle due to the forces imposed on the control stick during takeoff. The pitch trim was found in an almost full nose-down position, suggesting that the pilot may have been attempting to use the trim to arrest the airplane’s increasing nose-up attitude due to the locked control stick. Whether the pilot recognized that the control lock was engaged or believed he had a flight control problem could not be determined. Regardless, after takeoff during a dynamic and transitional phase of flight, there would have been minimal time to accurately diagnose the issue and disconnect the control lock. The intended purpose and destination of the flight was routine and there was no apparent time pressure present. The pilot was reported to be extremely thorough about performing preflight checks, and according to his wife, the expected duration of his normal preflight activities would not have allowed him to depart when he did. The pilot had limited experience in the accident airplane, which could explain why he did not remove the control lock during the preflight inspection. There was no video evidence to provide insight into the duration and scope of the pilot’s preflight inspection; however, omission of the preflight control check was uncharacteristic given his extensive flight experience, and the reason it was not performed could not be determined. While omission of the control check is consistent with a pilot rushing or distracted, and the short duration from taxi to takeoff would have reduced this pilot’s opportunity to detect his error, the investigation was not able to determine the reason it was not performed. Had the pilot completed a functional check of the controls before initiating takeoff, the presence of the lock would have been detected and the accident would have been prevented. Although the pilot’s autopsy demonstrated the presence of heart disease, which posed an increased risk of an impairing or incapacitating cardiac event, heart disease is unlikely to have caused inattention. It is also unlikely that the pilot was incapacitated by a cardiac event because his final radio transmission showed that he was aware and speaking after the onset of loss of control. Thus, it is unlikely that the pilot’s heart disease contributed to the accident.

Flight Manual The airplane’s flight manual was located in the airplane after the accident. The preflight check section contained an item for removing the flight control lock. The before take-off section stated that the pilot should, “check for freedom of movement and maximum range of travel in both directions.” The flight characteristics section described aircraft control with the trim system, and stated: Trim changes caused by flap movements are notable. However, the aircraft can always be controlled by using non excessive stick forces. A maximum of 4 to 5 kg in force variations is possible. In any case, these forces are quickly avoidable by the use of trim. Flap extension causes nose-up moment. During flap maneuvering it is possible to keep the stick longitudinal force almost nil at any moment by keeping the electric trim button pushed down in the opposite direction. Trim changes due to variations in engine rpm are much slighter, although remaining noticeable. An increase in power causes nose-up moment. Even without using the trim the aircraft remains perfectly controllable by means of slight stick movements. The pilot was a retired naval aviator, and current air show performer, with extensive flight experience in a broad range of aircraft. He held a commercial pilot certificate with ratings for airplane single-engine land and sea, airplane multi-engine land, and instrument airplane. At the time of his last medical examination, on October 29, 2020, he reported 6,500 total hours of civilian flight experience. The pilot’s logbooks were not available for review. The pilot purchased the airplane on April 21, 2021, and it was delivered to him in June by a friend, who was also a flight instructor. The instructor flew with the pilot for the first flight after delivery, during which they performed slow flight, stalls, steep turns, and multiple stop-and-go landings. The instructor stated that the pilot demonstrated proficiency in the operation of the airplane, and at no time did he need to take the controls. The instructor stated that, before their first flight, the pilot performed a very thorough and detailed walk-around, lasting approximately 90 minutes. He was particularly impressed with his “exemplary” checklist discipline, both during that flight, and when he had flown with the pilot previously. During the preflight, he observed the pilot perform a full check of the flight controls to verify proper movement and operation. They discussed the control lock operation, and the pilot stated that it was very similar to the lock used on other airplanes he had owned and flown. Varying accounts indicated that the pilot had flown the airplane about twenty times since purchase. The pilot’s wife had flown with him to LWS earlier in the day in their other airplane. She stated that she left him at the airport at 1110, at which time the accident airplane was still in the hangar. She stated that normally he would perform preflight checks after the airplane had been pulled out of the hangar, and that he was methodical and slow. She expressed surprise that he could have performed all his checks and still departed by the accident time. The general manager for the fixed base operator (FBO) next to the hangar where the pilot stored his airplane stated that he had known the pilot for many years, and that he routinely observed him perform an engine runup at the approach end of the runway before takeoff in all the airplanes he flew. He stated that he had never seen the pilot perform an intersection takeoff from midfield, and that the pilot’s preflight inspections took a very long time. On his most recent Federal Aviation Administration (FAA) medical certificate application, the pilot reported using the prescription medication lisinopril to treat high blood pressure, for which he was qualified under Conditions Aviation Medical Examiners Can Issue (CACI) criteria. He also reported using the prescription medication levothyroxine to treat low thyroid hormone, for which he was also CACI qualified. Lisinopril and levothyroxine generally are not considered impairing. No significant issues were identified, and the pilot was issued a second-class medical certificate limited by a requirement to have available glasses for near vision. The Spokane County Office of the Medical Examiner performed the pilot’s autopsy. According to the autopsy report, the cause of death was blunt force injuries. The autopsy revealed the presence of heart disease, with the heart being described as dilated, and mild coronary artery narrowing present. The autopsy did not identify any other significant natural disease. Toxicology testing on specimens from the pilot by both the FAA Forensic Sciences Laboratory and NMS Labs (on behalf of the Office of the Medical Examiner) revealed negative results, and ethanol was not detected in peripheral blood. The airplane was manufactured in Italy in 1977, imported into the United States in 1997, and issued an experimental-exhibition special airworthiness certificate in February 1998. The airplane was a single-engine, all-metal, high-wing, with a fixed tailwheel landing gear configuration. The cabin was enclosed and was equipped with conventional flight controls for two pilots in a tandem configuration. It had been upgraded with the installation of an avionics suite and autopilot. It was equipped with a 400-shaft-horsepower Allison M250-B17B turbine engine. The last condition inspection was completed on May 3, 2021, at an airplane total time of 509.5 hours of operation. The initial impact point was an area of disturbed ground consistent with a left wing strike about 30 ft from the main wreckage. A large, shallow impact crater, consistent with impact from the engine, was found between the initial impact point and the main wreckage. The wings sustained impact and thermal damage and remained partially attached to the fuselage. The forward fuselage sustained thermal damage and crush damage focused on the left side. The engine remained attached to the airframe. The propeller assembly separated from the engine and was found on the runway adjacent to the debris field. Disassembly of the engine revealed evidence that it was producing power at impact, including torsional overload of the turbine to compressor coupling and power turbine to pinion gear shaft, along with multiple compressor blade stages that displayed detached airfoils that were bent opposite the direction of rotation. The propeller blades exhibited signatures of stoppage at high power and high impact angle, including chordwise/rotational scoring, leading edge gouges, and compound twisting and bending opposite the direction of rotation. The pilot’s seat remained engaged and locked to both of its seat rails and was just forward of the midrange position. The forward and aft seat stops were intact and undamaged. The rear seat was in the center of its travel range, and similarly attached and engaged to both of its seat rails. The left and right elevators remained attached to each other and the control cable bellcrank. Elevator control cable continuity was established from the bellcrank assembly to the aft control stick, which remained connected to the forward stick via its interconnect tube. The left elevator was fitted with a servo tab, which was intact and remained connected to the elevator assembly. The right elevator was equipped with a pilot-controlled trim tab operated by a cable-driven jackscrew in the right horizontal stabilizer. The trim tab was electrically-controlled through a switch located in each control stick, with provisions for manual control through a wheel positioned on the left side of the pilot’s station. The jackscrew extension length corresponded to the tab being set to an almost full tab-up (airplane nose-down) position. The only undamaged component of the autopilot was the Garmin GSA-28 elevator pitch control servo. It