As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PIT- FL 1185, AT APPROXIMATELY 4000 FEET AGL AFTER TAKEOFF, PASSENGER NOTED A NACELLE ACCESS DOOR ON THE LEFT ENGINE DEPARTING THE AIRCRAFT. FLIGHT CREW VERIFIED THE INCIDENT. FLIGHT RETURNED TO PIT AND LANDED WITH NO FURTHER INCIDENT. MAINTENANCE REPLACED THE ACCESS DOOR. (M)