Dual Pilot and Single Pilot Operations – Hierarchical Task Decomposition Analysis of Doing More with Less John Huddlestone (&) , Don Harris, Dale Richards, Steve Scott, and Rod Sears Coventry University, Coventry, UK {john.huddlestone,don.harris,dale.richards,steve. scott}@coventry.ac.uk, wilts8874@hotmail.co.uk Abstract. An operational concept for single pilot operations is being developed as part of the work of the Future Flight Deck Technologies project. The under- pinning construct is that multiple single-pilot aircraft will be supported by a ground-based team using one or more ground stations to interact with the pilots and their aircraft. Concept development required detailed analysis of two-pilot operations to identify the functions and interactions that the second pilot engages in, to facilitate their reallocation or adaptation within the new system architecture. The application of Hierarchical Task Analysis (HTA) in this context revealed a number of issues related to the representation and interpretation of sequencing information in plans in HTAs presented in graphical form. This paper identifies these issues and presents a new graphical notation, derived from software design notations, for presenting hierarchical task decompositions. The use of the nota- tion is illustrated with analysis examples from different phases of flight. Keywords: Hierarchical task decomposition Á Hierarchical task analysis Á Sub- goal hierarchy Á Plans Á Single-pilot operations 1 Introduction As part of the Future Flight Deck Technologies project, a concept of operations is being developed for Single Pilot Operations (SPO). The high-level concept that is being explored is based upon the notion of multiple single-pilot aircraft being supported by a ground-based team (or teams) using one or more ground stations to interact with the pilots and their aircraft, along with technological enhancements to the flight deck architecture to simplify tasks. To develop such a concept, consideration has to be given to how the functions currently executed by the second pilot on the flight deck can be redistributed within the new system architecture. This in turn requires a detailed analysis of current, two-pilot operations to identify the functions that have to be exe- cuted, the allocation those functions within the system, and the interactions between various actors executing those functions. Due to the scale and complexity of the flying task, Hierarchical Task Analysis (HTA) was selected as the first of a number of analytical techniques to be applied to © Springer International Publishing Switzerland 2015 D. Harris (Ed.): EPCE 2015, LNAI 9174, pp. 365–376, 2015. DOI: 10.1007/978-3-319-20373-7_35