“There were a lot of interference... static... but I heard mumbling from the other end.”
Mumbling? As in someone not speaking clearly or does he really mean not mumbling, but distorted due to the interference?
Interference. Departed 30 minutes sooner means approximately 200 nm distance ahead. Pretty normal not to be able to make clear contact.
However, they fly another hour and ten minutes. There is absolutely no excuse for the aircraft in distress not to make a call. Even if he lost or forgot to mKe a call to center, when company called, he would or should have tried the emergency frequency and make contact.
Mumbling?
Praying?