The authors present a frame work - the scientific approach - within which they suggest the currently in use techniques and processes associated with advanced crew system design, should be used. They advocate considering the cockpit and crew as components of a “Crew System”, an entity which must be responsive to requirements and needs the same way the more traditional systems must be responsive to requirements and needs. They strongly urge improved communications with the user and suggest increased activity be expended on the definition of the problem - what is the mission, and how does the User anticipate performing it? The use of various test facilities, ranging in sophistication from simple mockups to flight test aircraft, is discussed, with specific recommendations made as to how these test facilities should be used. Finally, they urge sustained first hand involvement of the user throughout the process - confirming mission requirements, exploring design alternatives and testing design concepts.