THE LOCAL CONTROLLER'S NOT UNDERSTANDING READ BACK OF RADIO COMMUNICATIONS. FACTORS INCLUDE THE PILOT-IN-COMMAND OF FLIGHT 73 NOT UNDERSTANDING VERBAL INSTRUCTIONS; LOCAL CONTROLLER NOT VISUALLY IDENTIFYING THE AIRCRAFT; AND INADEQUATE SURVEILLANCE (FAA) IN THE TOWER.

UNEXPECTED OPENING OF THE IL DOOR, WHICH CAUGHT THE PASSENGER BETWEEN IT AND THE BULKHEAD AS THE DOOR MOVED INWARD AND UPWARD. A SECONDARY CAUSE WAS THE FAILURE OF THE FLIGHT ATTENDANTS TO FOLLOW COMPANY PROCEDURES REQUIRING THEM TO GUARD ALL ENTRY DOORS DURING THE DEPLANING PROCESS.