What was found
MX DIVERSION DUE TO PAX DOOR SQUEAL. NO WARNING OR PRESSURE ISSUES WITH SQUEAL. JUST A VERY LOUD NOISE AFTER CLIMBING THROUGH 28000FT COMING FROM MAIN CABIN DOOR. PREFORMED NORMAL LANDING IN IAD AND MX HAS BEEN ADVISED. HIGH PITCH NOISE COMING FROM MAIN CABIN DOOR IN FLIGHT.REMOVED AND REPLACED PAX DOOR SEAL IAW CRJ 700 AMM 52-11-07-000/400-801-A01. PERFORMED LEAK CHECK OF THE PAX DOOR IAW CRJ700 AMM 52-00-00-790-801-A01, 21-31-00-910-801/802. LEAK CHECK GOOD AT THIS TIME.