Breadth and Depth of Technological Capabilities in Complex Product Systems: The Case of the Aircraft Engine Control System

This paper documents the case of the aircraft engine control system. It aims to offer a detailed picture of the dynamics of the technological capabilities of aircraft engine manufacturers in relation to a specific and increasingly important engine subsystem, namely the control system. It draws on a combination of detailed qualitative and quantitative data to construct two measures of firms' technological capabilities, namely breadth and depth. The paper shows that engine manufacturers develop and maintain a broad and deep range of capabilities in-house in order to retain their systems integration capabilities over time. In particular, as regards the breadth, the paper shows how engine makers have responded to the shift in technologies underlying the control system by enlarging their breadth of capabilities through dedicated in-house investments, as well as by forging links with universities and specialised suppliers. As regards the depth, the paper shows that engine makers do not only focus their capabilities on the architecture of the engine control system, but they deepen them also in component technologies. The paper argues that engine manufacturers need a deep understanding of components' inner functioning in order to be able to specify, assess, test and integrate components produced externally into the engine, as well as to coordinate and benefit from changes arising from fast-moving technological fields, such as digital electronics. On the basis of these results, it is argued that there is no perfect overlap between the technological boundaries and the production boundaries of firms developing complex, multitechnology products, such as aircraft engines. (C) 2000 Elsevier Science B.V. All rights reserved.