This paper reports on the application of a range of human computer interaction (HCI) methods to the redesign of an electronic flight bag (EFB), as part of a commercial software development project. Specifically, it focusses on the use of participatory design methods, for resolving EFB usability problems. The purpose of this case study is to: (a) Show how participatory design methods can be effectively combined with ethnographic techniques and more formal methods in HCI, for the development of human-friendly EFB systems, (b) Illuminate the specific EFB usability issues encountered in this research and related HCI solutions, (c) Generate an awareness of the challenges faced by HCI practitioners adapting HCI methods to meet commercial project constraints. The HCI methodology outlined in this case study may be of interest to practitioners tasked with process and technology envisionment and/or working with limited resources. Keywords Electronic flight bag (EFB)