With so much else crumbling, the transponder lies at the heart of this great mystery.
That the plane apparently continued flying for at least 45 minutes after its transponder signal was lost is all the more baffling.
The moment the transponder turned off means everything to the investigation—and it happened after the pilots said things were OK.
The tripwire for an unfolding plot to take control of the flight would be the transponder, operated by a switch beside the pilots.
The transponder is really the tripwire for whatever began to unfold on that jet.
Government officials now admit the data system and transponder quit communicating after the pilots said things were OK.
However, to use the phrase “switched off” in relation to the transponder and the ACARS was in itself prejudicial.