Renewal of interest in finding the cause for the Braniff Flight 542 crash occurred after Northwest Orient Airlines Flight 710 , another Electra model aircraft of the same kind as Flight 542 , disintegrated in-flight and crashed near Tell City , Indiana , on March 17 , 1960 . Following the second crash , CAB Chief Safety Investigator Phillip Goldstein was reported as saying : " The structure was subjected to forces greater than it was designed for . We have definite evidence of a wing failure . Why this wing failure , I do n't know . " Initial investigations into the second crash proved fruitless but after laborious testing investigators were able to find flaws in the aircraft which included an overly stiff wing , and outboard nacelles responding differently than intended in the design briefs . Further experimentation discovered that flutter in a nacelle can be passed on to even a " flutter-free " wing . Final work in the mystery also found that as the magnitude of the flutter grows , the frequency at which it vibrates decreases . In the case of the two Electra crashes the frequency of the flutter had lowered from five cycles per second to three , the same as the natural frequency of the wing , creating harmonic coupling . This harmonic coupling would have continued to cause ever larger wing vibrations until some part of the structure failed . Contributing to the two aircrafts ' demise was the stiffness of the wings and severe clear-air turbulence . Final analysis of the CAB , in its official Accident Report :
Northwest Orient Airlines Flight 710
Northwest Orient Airlines Flight 710
Braniff Flight 542