The role of 'know-how' in maintenance activities and reliability in a high-risk process control plant.

Using observation of a maintenance operator's activity and 'the history' that it produced as a basis, we will discuss the role of 'know-how' in maintenance activities, and particularly the problems raised by putting this knowledge into words. Second, we will underline the contribution of this know-how to the operational reliability of the facilities and we will investigate its being taken into account in work instructions. With such issues as a basis, we will conclude with the need for ergonomists to develop modes of interviewing to help people to put know-how into words, so that it is recognized and considered in maintenance activity organization.