What does Mode-S transponder do?

The Mode S is a secondary surveillance and communication system which supports Air Traffic Control (ATC). The Mode S also interrogates and receives aircraft position and altitude information from Air Traffic Control Radar Beacon System (ATCRBS) transponder equipped aircraft.

What is the difference between Mode C and Mode-S transponder?

Civil aircraft may be equipped with transponders capable of operating in different modes: Mode A equipment transmits an identifying code only. Mode C equipment enables the ATCO to see the aircraft altitude or flight level automatically. Mode S equipment has altitude capability and also permits data exchange.

Where is Mode-S transponder required?

Thus, we conclude that Mode S transponders are necessary for part 135 and part 121 operators (those not required to have TCAS II) and provide benefits beyond those considered in 1996. Mode S avionics now are available for all types of aircraft from general aviation to heavy commercial aircraft.

How does a Mode C transponder work?

Responses from a Mode A transponder include a four-digit identification code assigned by a ground controller via radio, which pilots update manually during flight. Mode C transponders also transmit altitude information, obtained from the aircraft’s barometric altimeter.

When is Mode C transponder required?

A working Mode C transponder is still required after the ADS-B Out rules take effect on January 1, 2020. If you have an older transponder, and especially if it has been reported as intermittent or is showing other less-than-stellar behavior, replacing it with a 1090 Extended Squitter product would give you both a reliable,…

What does the transponder Mode C transmit?

Civil aircraft may be equipped with transponders capable of operating in different modes: Mode A equipment transmits an identifying code only. Mode C equipment enables the ATCO to see the aircraft altitude or flight level automatically . Mode S equipment has altitude capability and also permits data exchange.

Where is a transponder required?

A transponder is required when overflying Class C airspace up to 10,000′. You also need one at and above 10,000′ MSL, everywhere over the contiguous US except when at or below 2,500′ AGL, unless your aircraft was certified without an electrical system and continues to not have one.