Chinook CH-47 Helicopter Ground Resonance Test and Self Destructs with Rear Tandem Rotor Breaking

Chinook CH-47 Helicopter Ground Resonance Test and Self Destructs with the Rear Tandem Rotor Breaking, and Causing the Destruction of the Aircraft. The following Wikipedia article extract detail he Ground Resonance condition “Ground resonance is a hazardous condition that can occur any time the rotor of a helicopter or autogyro is turning while the aircraft is on the ground. Similar in concept to the behavior of a washing machine when the clothes are concentrated at one point during the spin cycle, ground resonance can occur with a rotorcraft when the spacing between blades becomes irregular or the damping system, including drag hinge dampers, landing gear oleo struts, or wheel tire pressure, is operating out of limits. Ground resonance occurs at three rotor RPM bands, the first at about one-third of normal rotor speed, the second at a range including normal rotor speed, and the last in a range above normal rotor speed. Ground resonance is precipitated by a s