Writing practices are seen to be essential for professional engineers, yet many engineering students and academics struggle with written communication, despite years of interventions to improve student writing. Much has been written about the importance of getting engineering students to write, but there has been a little investigation of engineering academics' perceptions of writing practices in the curriculum, and the extent to which these practices are visible to their students and to the academics. This paper draws on research from an ongoing study into the invisibility of writing practices in the engineering curriculum using a practice architectures lens. The paper uses examples from the sites of practice of two participants in the study to argue that prevailing practices in engineering education constrain more than enable the development and practice of writing in the engineering curriculum.