What was found
ON 12/25/25, WE HAD AN INFLIGHT EMERGENCY DECLARED BY THE FLIGHT CREW FOR #1 ENGINE PROP SPEED ERRATIC. THE CREW REPORTED THE #1 ENGINE PROPELLER SPEED WAS JUMPING AROUND BETWEEN 1400 AND 1900 IN CLIMB SHORTLY AFTER TAKEOFF. THE CREW SAID ALL OTHER ENGINE INDICATIONS WERE NORMAL AND THE AIRCRAFT WAS NOT EXPERIENCING ANY ABNORMAL SOUNDS OR DIRECTIONAL CHANGES. HOWEVER, THEY DECLARED AN EMERGENCY AND LANDED WITHOUT INCIDENT SHORTLY THEREAFTER. WE FOUND THE #1 ENGINE PROPELLER TACH GENERATOR HOUSING LOOSE. THE SAFETY WIRE ON THE 4 SCREWS WAS PRESENT AND APPEARED UNDAMAGED BUT THE SCREWS WERE LOOSE AND THE HOUSING WAS LOOSE. AFTER REMOVING THE TACH GENERATOR, THE TACH SHAFT FELT VERY WOBBLY AND WOULD NOT SPIN/TURN EASILY AS COMPARED TO A NEW UNIT. WE REPLACED THE TACH GENERATOR AND THAT SEEMED TO HAVE SOLVED THE ERRATIC INDICATION PROBLEM.