Speed Mode FMS Speed Modes Engine Out Engine Out Type FCC Engaged Mode FCC Engaged Modes FMS Mode FMS Modes Flight Phase Flight Phase Type Requested Climb Speed Mode Climb Speed Mode

Recently, there has been a great deal of interest in the application of formal methods, in particular precise formal notations and automatic analysis tools, for the creation and analysis of artifacts of requirements engineering. In this paper we discuss the role of formal methods in requirements engineering (RE), emphasizing that in contrast to their more conventional application in RE for the creation and analysis of requirements speci cations, formal methods may be applied in a cost-e ective way to answer speci c questions about the domain by the construction and automated analysis of \domain models".