Subsequent to the departure of the skydivers, the airplane entered a spiral descent. The jump door, not the sky motive jump door listed on the airplane’s form 337, which had been approved by an faa inspector, entered a flutter condition. The pilot door, windshield and pilot door window separated during the descent. This flutter condition and separation of components resulted in the pilot being unable to control the airplane. Impact occurred in a 20 to 30 degree nose low attitude in approximately a 65 degree left angle of bank.