modec modes

[Lrjtcaptain]

someone define the difference between mode-s and mode-c.

a friend and i are arguing over the mode-s capablities....He seems to think that mode-s is an automatic aircraft id to ATC radar, hence they done need a descreit code utilizing stars or arts3. I am a controller, and anyone who needs to be radar id gets the tail number typed in to the system for the beacon code.....trying to look up mode-s but unable to find anything. Sounds like all it is good for is TCAS type stuff.

 

[sweptback]

One difference is a Mode-S transponder has a discrete code that is sent to ATC along with squawk and altitude. Mode-C is strictly squawk and altitude.

I'm not sure what is entirely done with that discrete code, but obviously it doesn't replace the squawk code for identification.

 

[bluffs4U]

Are you at it again? Thinking your right?

As quoted out of a Collins pilots guide " Mode S replies include all the info supplied by A and C plus a unique aircraft id, ie directly associated with the a/c regrisration or "N" number". Mode S direcly is not involved with TCAS, but it may be used in TCAS systems.