* Corresponding author: Tel.: #1-404-894-8280. E-mail address: dan.delaurentis@ae.gatech.edu (D.A. DeLaurentis). Aircraft Design 3 (2000) 79}101 A probabilistic approach for examining aircraft concept feasibility and viability Dimitri N. Mavris, Daniel A. DeLaurentis* Aerospace Systems Design Laboratory (ASDL), School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0150, USA Abstract A novel approach to assessing aircraft system feasibility and viability is presented, with special emphasis on modeling and estimating the impact of new technologies. The approach is an integral part of an overall stochastic, life-cycle design process under development by the authors, which is to address the new measure for system value: awordability. Stochastic methods are proposed since the design process is immersed in ambiguity and uncertainty, both of which vary with time as knowledge increases about the system behavior. The speci"c task addressed in this paper of examining system feasibility and viability is encapsulated in the "ve steps of the Concept Feasibility Assessment approach. The rationale and technical foundations of each step are explained, and the approach is compared to more traditional, deterministic means for examining a design space and evaluating technology impacts. Finally, the techniques are implemented on a supersonic transport design problem to highlight the power of the approach on a problem of signi"cant interest to the international aerospace community. Several innovative avenues for viewing the design and technology spaces are employed in assessing "rst feasibility and then viability for the problem.  2000 Elsevier Science Ltd. All rights reserved. 1. Introduction & motivation The "eld of aircraft design, and more recently the related "eld of multidisciplinary analysis and design optimization (MDA/MDO), has operated under a deterministic paradigm. In this setting, a design objective is identi"ed along with an associated set of design parameters that are varied to determine the settings that result in an extremal value for the design objective. Since these 1369-8869/00/$ - see front matter  2000 Elsevier Science Ltd. All rights reserved. PII: S 1 3 6 9 - 8 8 6 9 ( 0 0 ) 0 0 0 0 8 - 2