From the 1970s onward an aircraft with two-member crews, such as the F-15E Strike Eagle, F/A-18F Super Hornet or Su-34 Fullback and Dassault Rafale B have often featured programmable multi-function displays. These programs allow roles to be more flexible than previous generation aircraft. Multiple crew members can be responsible for detecting, targeting and engaging air-to-air or ground targets, communications, datalinks and/or defensive systems. Roles can be customized based on experience, expertise, workload, tactics, and weapons being employed. Pilots usually retain the responsibility for flying the aircraft in tactical situations. However, the crews of dedicated bomber aircraft usually retain distinct, rigidly-defined and conventional roles.