Bombardier introduced its Challenger 604 in 1995 as a major upgrade on the Challenger 601 design, incorporating more powerful engines, larger fuel supply, completely new undercarriage, structural improvements to wings and tail, and a new electronic flight instrumentation system. The Challenger 604 is a longer-range derivative of the 601-3R with a larger fuel capacity and upgraded CF34-3B engines. The Challenger 604 was also one of the first business jets designed with a super-critical wing.