Snowfalcon,
But every crew is only ever 90 seconds from voluntarily spearing into the ground/sea, as Egyptair showed.
Circuit breaker design isn't going to stop a deranged crew, or fraction thereof, of going postal.
Legacy aircraft can't have their power systems and the location of their avionics bays redesigned as a result of a one-off freak event. If you want a permanent locator, then fit an independent transponder.
I wonder if any knee-jerking legislators might consider having arbitrary numbers of security persons with much less education, training and judgement than the crew themselves installed in the jump seats to watch the crew and each other?