dessas
Whilst I agree a Mayday or ELT activation would be nice, and the PTT is right there on the sidestick, we do not know if the radios were tuned to guard, I suspect there was plenty going on around them that precluded setting up a frequency on the radio. Even tx-ing blind on whatever frequency they were on might not be heard if as is thought, they were in an area of an electrical storm.
Just my two rupees worth.
KW