How long will those recorders ping? I thought it was 30 days.
The battery's life is approximately thirty days.
If the plane flew for hours on autopilot and everyone on board was dead, there wouldn’t be any useful information on the black box or cockpit voice recorder anyway, would there? My understanding is the black box only records on a loop that is about 2 hours.
From the thread on airliners.net, I gather that there are two recorders. They are on a continuous two hour and two and a half hour loop respectively. In other words, we will never find out what happened in the cockpit during those critical first two hours of the flight.