What was found
MAIN DOOR: MAIN DOOR IS FLUSH WITH THE FUSELAGE BUT HANDLE REFUSES TO RESEAT ITSELF.. THE PRESSURE RELIEF VALVE DOOR IS ADJAR.... THE DOOR IS UNOPENABLE FROM CREW POINT OF VIEW.. CORRECTIVE ACTION; FOUND CABIN VENT DOOR PLUNGER TO BE STUCK BEHIND THE ACTUATING LUG ON THE DOOR HANDLE PREVENTING DOOR HANDLE FROM STOWING. DEPRESSED CABIN VENT DOOR PLUNGER, MASSAGED SMALL DENT FROM PLUNGER WHICH WAS ALLOWING IT TO SLIP BEHIND THE DOOR HANDLE ACTUATING LUG WHEN THE DOOR HANDLE WAS IN AN OVERTRAVEL POSITION, AND STOWED HANDLE IAW THE BOMBARDIER CHALLENGER 650AMM PART II TASK 52-11-00-410-801, OPERATIONAL CHECKS SATISFACTORY.