What was found
DURING FLIGHT, PASSENGERS NOTIFIED US OF A SQUEAL COMING FROM THE BACK. THE SQUEAL SEEMED TO BE COMING FROM THE UPPER EMERGENCY EXIT AREA. PREPARED AND PRESSURIZED THE AIRCRAFT AND WE DID NOT HEAR ANY NOISE AFTER DEPRESSURIZING WE REMOVED THE EMER DOOR AND INSPECTED THE SEAL. THE TOP FORWARD CORNER SEEMED A LITTLE MORE WORN THAN THE OTHER CORNERS AND THE SEAL WAS SLATHERED IN PETROLEUM JELLY. WE REMOVED THE SEAL (P/N: 9914815-1, S/N: N/A), CLEANED UP ALL THE PETROLEUM JELLY AND REPLACED WITH A CUSTOMER SUPPLIED NEW SEAL. REINSTALLED THE DOOR AND REPRESSURIZED, NO LEAKS DETECTED. WORK PERFORMED IAW CESSNA 680A AMM 52-20-15.