The latest media report on the 100-minute-incommunicado
Below is what I wrote for another forum.
The report has it that both of them were having their meals without wearing their headsets; the boom mic gets in the way if (s)he does not take the headset off while eating. One thing that makes this explanation fishy is the fact that they usually leave the (Loud) speaker on and turn up the volume while munching so as to listen to the directions from the ATC.
Anyhow, for the whole 100 minute-incommunicado, one thought the other was in contact with the controller.
They don't seem to talk much in the flightdeck. Another case of bad CRM.
It must have been quite interesting when the TCAS alert and resolution advisories went off right before the fighters popped up close enough to see the faces of the freighter crew.