The A300-600 development of the earlier A300B4 incorporated a number of significant improvements and refinements, foremost being a two crew flightdeck and increased range.
Apart from the two crew EFIS cockpit, with digital avionics based on that developed for the A310, changes included the A310's tail empennage which increased freight and passenger payloads, small winglets (an option from 1989, standard from 1991), simplified systems, greater use of composites, Fowler flaps and increased camber on the wings, new brakes and APU, and improved payload/range through an extensive drag reducing airframe clean up and new engines. First flight for the A300-600 was on July 8 1983, the first airline delivery was in March 1984.
The A300-600 was further developed into the longer range A300-600R, its extended range courtesy of a fuel trim tank in the tailplane and higher maximum takeoff weights. First flight was on December 9 1987, first delivery was April 20 1988 (to American Airlines).
Convertible freight/passenger versions of all variants of the A300 have been offered, as has the all freight A300F4-600. The first new build pure freighter A300, one of 36 ordered for Federal Express, flew in December 1993. UPS is another major A300-600F customer, following its September 1998 order for 30. Airbus also offers conversion packages of existing passenger A300s into freighters with a left side forward freight door and strengthened floor.