What was found
(CAN) ACFT EXPERIENCED THE RT PROPELLER GOING TO FLAT PITCH SHORT FINAL, WITH ASSOCIATED YAW OF 35-40 DEGREES. FULL RUDDER AUTHORITY WAS UNABLE TO CORRECT THE YAW. A GO-AROUND WAS INITIATED. GIVEN THE VFR CONDITIONS THE ACFT RETURNED IN THE PATTERN FOR A SECOND ATTEMPT. NO ABNORMAL OR WARNING ANNUNCIATORS WERE ILLUMINATED. THE SECOND ATTEMPT RESULTED IN THE SAME NON-RECOVERABLE YAW. A SECOND GO-AROUND WAS INITIATED. ACFT RETURNED A THIRD TIME TO THE LONGEST AVAILABLE RUNWAY AND LANDED WITH APPROXIMATELY 15-18 PERCENT POWER. THE THIRD ATTEMPT RESULTED IN A NORMAL LANDING. AFTER LANDING, THE SUBSEQUENT TAXI AND GROUND MANEUVERING WAS NORMAL AND UNEVENTFUL.