articleUnited Parcel Service CEO Carol Tome said Tuesday that the company is officially retiring its fleet of McDonnell Douglas MD-11 cargo planes after one of them was involved in a deadly crash in Louisville. Over the next 15 months, the company plans to receive about 18 new Boeing 767 aircraft, with 15 expected to be delivered this year. The MD-11 fleet had already been pulled from service in November, when the company decided to ground the aircraft following its involvement in a deadly Nov. 4 crash. UPS WARNS OF ‘MONTHS-LONG’ DISRUPTIONS AFTER GROUNDING ENTIRE JET FLEET AFTER DEADLY KENTUCKY CRASHThe UPS cargo plane's engine fell off and burst into flames shortly after takeoff from Louisville Muhammad Ali International Airport . FORD TEMPORARILY HALTS KENTUCKY PLANT OPERATIONS AFTER DEADLY UPS PLANE CRASHInitially, UPS had planned to bring the fleet back into service and began working to meet Federal Aviation Administration (FAA) guidelines before returning to service.