ELTs are activated either manually or by sudden deceleration with a g-switch. Plus, the life rafts aboard have ELTs in them which are activated when the raft is deployed.
So if it did a belly landing, unlike AF flight 447, at least one would have been activated. With a belly landing that might give the crew to deploy the life raft thus activating the second one.
There was not a distress beacon on AF flight 447 but there was debris found plus signs of oil or jet fuel on the water surface, aircraft seats, an orange buoy, dead bodies, a passenger’s briefcase, and other things.
We haven’t seen any distress beacons nor crash debris.
In that case, the pilot would know that and nosedive to get the plane under water before the ELT(s) could activate.
We havent seen any distress beacons nor crash debris.
I would think nosediving in the southern Indian Ocean or northern Antarctic Ocean would explain that.