In 1999, the European aviation regulatory agency (JAA) required that all aircraft flying IFR flights have Mode S Transponders by April 2003 and Mode-S for all VFR flights by April 2005. A typical Level 2 Mode S transponder downlinks aircraft parameters such as position, altitude, velocity, and attitude to ATC thus reducing the workload for ATC interrogation. In addition, all Part 91 aircraft installing new transponder must install a Mode S transponder. The FAA has plans for Mode S requirements in the future for all US registered aircraft although no deadlines have been firmly established.