On March 6, 1998, about 0200 central standard time, a Douglas DC-10-30F, N303FE, registered to Federal Express Corporation, operating as a 14 CFR Part 121 supplemental domestic international cargo flight, experienced a failure of the pressurization outflow valve on the left main cargo door, while conducting engine shutdown procedures on the parking ramp at Memphis International Airport, Memphis, Tennessee. Visual meteorological conditions prevailed and an IFR flight plan was filed. The airplane sustained no damage. The airline transport-rated pilot-in-command, first officer, second officer, and four jump seat riders reported no injuries. The flight originated from San Diego, California, about 3 hours 3 minutes before the accident. The PIC stated he parked the airplane on the FedEx ramp and the crew entry doors would not open, and he suspected the airplane had not fully depressurized. He instructed the second officer to make sure the airplane was depressurized. Before he had the opportunity to run the checklist, they heard a loud bang. The second officer opened the cabin outflow valve and the crew doors opened normally. The PIC exited the airplane and observed a ramp worker was on the ramp injured. The second officer stated he departed the cockpit after the airplane was parked. He disarmed the entry doors and returned to the cockpit to complete the shutdown and termination checklists. While accomplishing this, he was informed that the entry doors would not open, and to check the airplane pressurization. The airplane had not fully depressurized automatically. While manually opening the outflow valve, he heard a bang sound from the rear. He continued with the checklist, and wrote up the pressurization system in the airplane logbook. Upon exiting the airplane he became aware of the accident. The injured equipment loader stated when he approached the airplane, the upper and lower beacons were off. He walked up and released the lever on the door. The door blew and he was knocked off the loader. Ground personnel stated after the airplane was blocked and the airplane engines were shut down, that the ground team proceeded to mate the ground equipment and crew stairs to the airplane. The beacon was still on. Another ground crewmember knocked on the crew door and instructed the flight crew to shut off the beacon. As the ground crewmember was pushing the button, another ground crewmember yelled from the ground to stop. He turned turned around, turned back, looked into the cockpit, heard a loud noise, and observed the equipment loader falling off the loader. Review of Federal Express Corporation, Aircraft Ramp Operations Procedures, R2-85-5 Ramp Safety Policy states, "When driving or operating ground equipment, the operator is responsible for the following:... * Not approaching an arriving aircraft until it has come to a complete stop at its parking position, the engines are shut down and have completed a rundown, the wheels are chocked, and the red rotating beacons are turned off."