DESIGN OF INSTRUMENT DIALS FOR EASE OF READING

THIS survey of psychological research in the field of reading aircraft and other instruments shows that the majority of serious errors cannot be eliminated by mere improvements in visibility, such as could be obtained by increases in size or illumination.

Rather, it is said, we must find methods of indication that actually simplify the interpretational processes interposed between the seeing of an instrument and the making of an appropriate control action.

For instance, it appears that most errors in the reading of such instruments as the altimeter can be eliminated by the use of a single-pointer instrument with a counter to indicate the number of revolutions of the pointer.