Plain English Meaning

A short code starting with 'W' that the GPS uses to label and identify a specific WAAS approach, matching what is printed on the approach chart.

Full Definition

A four-character alphanumeric code, beginning with the letter W, that uniquely designates a WAAS-based instrument approach procedure within the avionics database. The identifier links the loaded approach in the GPS/FMS to the published chart so the equipment can confirm it is flying the correct procedure.

Context Anchor

Seen on instrument approach charts and in WAAS-capable GPS navigators when selecting or checking an RNAV (GPS) approach.

Derivation

WAAS stands for Wide Area Augmentation System, the -based that improves GPS enough to support . The leading 'W' in the identifier signals that the approach depends on WAAS.