Spectrum Crash Cause Points To Misrigged Controls
The NTSB today released the preliminary report for last Tuesday’s fatal crash of the Spectrum 33 prototype. According to the Safety Board, witnesses said the airplane entered a right roll almost immediately after takeoff from Spanish Fork Airport, Utah. The roll continued to about 90 degrees right wing down when the right wingtip hit the ground. Examination of the accident site revealed that the initial impact point was about 150 feet right of the Runway 30 centerline. The main wreckage came to rest about 750 feet from the initial impact point and included the forward fuselage, aft fuselage and a majority of the wing structure. The NTSB found no evidence of any pre-existing failures of the airplane’s structure. However, “examination of the translation linkage on the aft side of the aft pressure bulkhead revealed that it was connected in a manner that reversed the roll control…the linkage was connected such that left roll input from the side sticks would have deflected the ailerons to produce right roll of the airplane, and right roll input from the side sticks would have deflected the ailerons to produce left roll of the airplane.” Between June 30 and the accident flight, the prototype underwent maintenance to stiffen the main landing gear struts. Due to insufficient clearance, the aileron upper torque tube V-bracket had to be redesigned, which entailed removal of a portion of the translation linkage. Spectrum president Austin Blue told AIN that in the aftermath of the crash the company has “renewed our determination to continue with the program.” He said the next test aircraft will be closer to a production configuration and will be designed to ensure that the controls cannot be misrigged. First flight of that aircraft is expected sometime next year. Blue said Spectrum will release more definitive program details in October at the NBAA Convention.