As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT SIDE WINDOW (LOCATED ON PILOT'S DOOR) DEPARTED AIRCRAFT DURING FLIGHT WHEN WINDOW WAS OPENED. FOLLOWING AN EXAMINATION OF THE DOOR ON THE AIRCRAFT, IT APPEARED THAT BOTH THE FORWARD AND REAR HINGE PINS SHEARED ALLOWING THE WINDOW AND WINDOW FRAME TO SEPARATE FROM THE AIRCRAFT. THERE WAS NO DAMAGE TO THE HINGE HALVES SECURED TO THE DOOR FRAME.