As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOTH PROPELLERS GO INTO TIP FLUTTER AT ENGINE POWER SETTINGS AT AND ABOVE 1,800 FEET/POUNDS OF TORQUE. HIGH FREQUENCY VIBRATION CAN BE FELT THROUGHOUT THE ENTIRE AIRCRAFT. BLADE TIPS TOO THIN AT TIPS. MANUFACTURER HAS NO STANDARDS FOR MINIMUM THICKNESS AT THIS BLADE STATION.