Airports
FAA to Pilots: Keep Transponders On While Taxiing
Runway safety systems use data from transponders to obtain accurate aircraft and vehicle locations to increase airport surface safety and efficiency.

Safety Alert for Operators 15006 was published by the FAA last week to ensure that pilots realize the need to keep their aircraft transponders turned on to the altitude-reporting mode even when operational on the ground in airport movement areas. The FAA uses runway safety systems, such as airport surface detection equipment model X (ASDE-X) and advanced surface movement guidance and control system (A-SMGCS), at many airports in the U.S. to determine aircraft and vehicle locations when operating on an airport surface.