olandese:
Seems like a diode shorting or a major defect in the cell are the only reasons I can think of for an ELT to decide to self immolate.
More curious to me is why we need a 50+ hour transmit time on a 406 ELT. The Satellites should get a very good position fix in under an hour, even if the ELT isn't reporting last known position. It's not like we're using a loop antenna on 121.5 to find the position anymore. Maybe go back to alkaline batteries and accept an under 12 hour transmit time??