What’s in a Name?
You’ll hear a lot of terms related to airport surface safety. To be sure we’re all on the same page, here’s the official “what’s what.”
Runway Incursion. A runway incursion is any occurrence at an airport involving the incorrect presence of an aircraft, vehicle, or person on the protected area of a surface designated for aircraft landing and takeoff. For obvious reasons, runway incursions are the main source of surface risk in the National Airspace System (NAS). Examples include the following: (a) An aircraft fails to stop and crosses the runway holding position markings without a clearance. (b) An aircraft takes off or lands on the correct (or incorrect) runway without a clearance.
Runway Confusion. This term describes landing or departing, or attempting to land or depart, from the wrong runway or from a taxiway. Runway confusion is a subcategory of either a runway incursion or surface incident, and you may hear this kind of activity described as a “wrong surface event,” or WSE. These incidents have become a top priority for the FAA. Runway Excursion. You might think of an “excursion” as something fun, but a runway excursion is a trip to avoid — as you can probably guess, it describes veering off or overrunning the runway surface.
Surface Incident. A surface incident is an unauthorized or unapproved movement within the designated movement area (excluding runway incursions), or an occurrence that actually or potentially affects safety of flight in an area associated with the operation of aircraft. Surface incidents can arise from a mix of other causes. For example, the overflight incident involving Air Canada 759 at the San Francisco airport a few years back was a surface incident attributed to runway confusion.
Surface Event. This one describes an occurrence at an airport involving a pedestrian, vehicle, or aircraft on the defined airport movement area that involves either a runway excursion, or an incorrect presence, unauthorized movement, or occurrence that affects or could affect the safety of flight of an aircraft. For example, an aircraft taxis from the ramp non-movement area into a taxiway (movement area) without a clearance.
Source: https://medium.com/faa/the-scoop-on-surface-safety-a40381f51a4f