Which statement correctly defines the station number?

• A. A specific measured distance from the datum to points on the aircraft
• B. An assembly's position in the drawing set
• C. A dimension of a part
• D. The date of manufacture

Answer: (A)

The station number identifies a location along the aircraft’s length by a fixed distance from a reference datum. In practice, engineers define a datum line or plane, and each station is a measured distance along the longitudinal axis from that datum to a point or feature on the airframe. This lets technicians pinpoint exact locations on the aircraft for fittings, lines, or components, independent of drawing layout or part size. For example, if the datum is at the nose, station 120 means the feature lies 120 units aft of that datum along the centerline.

This isn’t about where an assembly sits in the drawing set, nor is it a dimension of a specific part, and it isn’t the date of manufacture. It’s all about locating a point along the aircraft relative to the defined datum.