What was found
DURING CLIMB THE FORWARD ENTRY DOOR EXIBITED AN EXTREMELY LOUD SQUEAL IN FLIGHT, THE SOUND DID NOT ALTER DUE TO CHANGES IN AIRSPEED, ALTITUDE OR CABIN PRESSURE. THE FLIGHT CREW ELECTED TO RETURN TO MSP, THE POINT OF ORIGIN. REPOSITIONED THE DOOR SNUBBER, AND LOWER HINGE SEAL, RECONDITIONED LOWER DOOR FRAME CORNERS. PRESSURIZED AIRCRAFT TO 7.0 PSI, OPERATIONAL CHECK GOOD.