Attritable design trades: Reliability and cost implications for unmanned aircraft

Aircraft are generally designed and produced to be maintainable. Recently, the U.S. Air Force, due to increasing aircraft unit costs, began to investigate early conceptual designs for attritable (unmanned) aircraft. Attritability is a system characteristic that trades reliability and maintainability for low-cost of a system meant for reuse - at least a few times. This characteristic is affected by system attributes like reliability, redundancy, reparability and cost. This concept of a trading these attributes for lower cost presents a very interesting design space for systems engineers, but it presents several challenges. This paper introduces the system characteristic of attritability and shows the far-reaching impacts and challenges that this novel attribute presents through the use of reliability modeling and cost estimation techniques.

I. Introduction

Increases in production, deployment, and sustainment costs have negatively affected the acquisition of new DoD systems for many years [4]. The historical rise of military aircraft per-unit cost and reduction in the number of military aircraft acquired was a trend observed by former Under Secretary of the Army Norman Augustine [2]. In 1983, he warned that cost growth alarmingly decreases the buying power of the DoD budget. To overcome this hurdle, DoD as recently outlined various technologies to address better buying power, to include human-machine collaboration, combat teaming, assisted human operations, and autonomous weapons [3]. Correspondingly, the Air Force has extended its efforts to include expendable and attritable assets [5].