Examples from the Web for transponder
The tripwire for an unfolding plot to take control of the flight would be the transponder, operated by a switch beside the pilots.
However, to use the phrase “switched off” in relation to the transponder and the ACARS was in itself prejudicial.
With so much else crumbling, the transponder lies at the heart of this great mystery.
Government officials now admit the data system and transponder quit communicating after the pilots said things were OK.
The moment the transponder turned off means everything to the investigation—and it happened after the pilots said things were OK.
British Dictionary definitions for transponder
Word Origin for transponder
Word Origin and History for transponder
1945, from trans(mit) + (res)pond + agent noun suffix -er (1).