ERA17FA038 · Quad City CHALLENGER II

The student pilot and flight instructor were conducting an instructional flight in an experimental amateur-built airplane about 3/4 mile east of the departure airport in light winds with no adverse weather nearby. The investigation could not determine which of the pilots was flying the airplane at the time of the accident. One witness reported hearing the engine noise decrease before seeing the airplane descend and then abruptly pitch up and hearing the engine noise increase. He then heard a loud sound and saw a wing separate from the fuselage. Subsequently, the airplane entered an uncontrolled descent and impacted trees and terrain. Another witness reported seeing the airplane flying overhead and hearing the engine running. He also saw a parachute trailing behind the airplane while it was descending.

Examination of the wreckage revealed that both the forward and aft right wing "Rony" attachment brackets had failed. The brackets were separated from the root tube and the root tube was fractured on all four sides at the aft wing attachment bracket mounting holes. All the attachment brackets and root tube fracture surfaces were consistent with overload failure and showed no evidence of preexisting damage, cracks, or corrosion. Examination of the engine revealed no evidence of any preimpact mechanical failures or malfunctions that would have precluded normal operation. Although the ballistic recovery airframe parachute system was found deployed, the airplane impacted tress before the parachute could inflate.

The airplane had been involved in a hard landing about 1 week before the accident. Two days before the accident, the student, who had previously been an airplane mechanic in the U.S. Navy, replaced a steel cable between the two landing gear legs, which had been broken during the hard landing. However, no evidence was found indicating that the hard landing or the repairs contributed to the failure of the right wing attachment brackets and subsequent wing separation.

Although the toxicology testing of specimens from the flight instructor detected hydrocodone in the liver, the investigation could not determine whether the flight instructor's use of hydrocodone before the flight contributed to the accident. Although ethanol was detected in the student's muscle, it was not detected in the liver, and no n-propanol was detected in the liver, which is consistent with postmortem production of ethanol.

Given the witness's statement and the wreckage evidence, it is likely the airplane was pitched up abruptly following a descent, which resulted in the in-flight separation of the right wing and the subsequent uncontrolled descent.

Verbatim NTSB analysis and probable cause from the NTSB dataset