The pilots didn’t transmit anything after the plane was in trouble. Those were all automated transmissions from the plane’s systems. The last actual communication from the pilots was quite a bit earlier, and quite routine, just noting thunderstorm activity which is to be expected along that route.
That has been bothering me in following all these threads. Has it occurred to anyone that they weren't able to transmit anything. Were they incapacitated in some way? Hmmm. It's been said that communication is the last priority but still, how long to say Mayday? JMO.