Runway Awareness and Advisory System

The Runway Awareness and Advisory System (RAAS) is an electronic detection system that notifies aircraft flight crews on the ground of their position relative to their allocated runway.
Operation.
 RAAS functions by providing audible alerts to confirm runway identification, and also provides an aural alarm if it detects undue acceleration (indicating an attempt to take off) while the aircraft is on any taxiway instead of a designated runway. Its function is possible by a software enhancement to the aircraft's terrain awareness and warning system (TAWS) or enhanced ground proximity warning system (EGPWS). The system was developed by Honeywell.
Entrance into service.
Alaska Airlines announced in September 2008 that its entire airline fleet of Boeing 737s will be equipped with RAAS by the end of September. That will be the first airline fleet to be completely equipped with this system. In 2015 the largest European low-cost carrier Ryanair announced it would equip their entire fleet by the end of 2016 with RAAS as an investment in its commitment to safety.