The 100 series 727’s that I flew , I think, had the DME calibrated in miles and tenths.
Many thanks. I am writing a book on Northwest Flight 305 of 11.24.1971. One of my research tasks was to determine the margin of uncertainty of the three DME reports (14m south of SEA, 19m south of SEA, and 23m south of PDX. I had been wondering why they reported whole miles and whether the instrument precluded a more precise reading.