A mode S transponder is silent when it is not interrogated.
A. True
B. False
I had been asked this question by my school principal while I was bunking the class.
This question is from Modes S System topic in chapter Surveillance Systems, Mapping and Multimode Radars of Avionics
Right option is B. False
Easy explanation: Usually, a transponder remains silent when not interrogated. However, being an integral part of TCAS requires the occasional spontaneous mode S transmissions.