Effective Sept 30, 2010, all U.S. airport control towers will use the new phraseology: “Line up and wait,” to clear aircraft into takeoff position and wait for further clearance. The new phrase replaces the old phrase, “Position and hold.” The proper response to this clearance is: “Your_callsign, line up and wait.” Be sure to include the assigned runway at the end of your transmission.”
Example: “Cessna 729LC, line up and wait, Runway 27R.”
The new phrasing will align U.S. terminology with ICAO terminology. It will create consistency in this particular radio call so pilots hear the same instructions no matter where they are flying in the world. The FAA believes this will help eliminate confusion for aircrews flying internationally who previously heard one type of clearance in the U.S. and another type abroad. They say the change will reduce the chances of a runway incursion for pilots who are waiting for takeoff clearance.
For more information, follow this link to the FAA’s page on the phrase change.