The failure to remove a control lock is blamed for the crash that killed airshow legend Dale “Snort” Snodgrass in Idaho last year.
According to the final report from the National Transportation Safety Board (NTSB) released Thursday, the control lock was still installed when Snodgrass attempted to take off in his SIAI Marchetti from Nez Perce County Airport (KLWS) in Lewiston, Idaho. This prevented Snodgrass from lowering the nose when the aircraft pitched up aggressively after takeoff, then entered a stall-spin situation from which it was not recovered.
The report says the airplane was equipped with a flight control-lock system that immobilized the aileron and elevator controls but still allowed for near-full movement of the rudder and tailwheel. This made it possible for the pilot to taxi the aircraft.
The flight control system consisted of a pivoting, U-shaped control lock tube mounted permanently to the rudder pedal assembly with a forward-facing locking arm mounted to the pilot’s control stick.
The post-crash investigation found evidence that the control lock was still engaged at the time of the crash. The NTSB noted, “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 report continues, “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.”
Investigators noted that the pitch trim of the accident aircraft was found in an almost full nose-down position, suggesting that Snodgrass may have been attempting to use the trim to arrest the airplane’s increasing nose-up attitude due to the locked control stick.
Video of the June 24, 2021, accident shows Snodgrass initiating an intersection takeoff from Runway 12. The takeoff roll consists of about 400 feet before the aircraft lifts off, pitching nose-up at about a 45-degree angle. The aircraft is still climbing when at an altitude of about 80 feet agl, it then rolls 90 degrees to the left and the nose drops. The aircraft continued to roll to the left as it plunged to the ground, hitting the dirt in a nose-down attitude. There was a post-impact fire.
Snodgrass was in communication with the tower at the time of the accident. He acknowledged the takeoff clearance and an advisory for a frequency change, and then let out expletives as he lost control of the aircraft.
Snodgrass was a real-life Top Gun naval aviator, flying F-14s from carriers and later as an airshow demonstration pilot in vintage warbirds. At the time of the accident he had an estimated 6,500 hours of flight experience, of which 20 hours were in the accident airplane.
Contemporaries of Snodgrass say he was known for being a meticulous pilot who did not rush preflight inspections.
As part of the investigation, the NTSB interviewed pilots who owned similar aircraft in regard to the control lock. It was noted that although the control lock is painted red, its orientation when engaged is difficult for a pilot to see from the cockpit.
According to the NTSB report, “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 report suggests that Snodgrass did not perform a pre-takeoff control check, stating, “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.”