If it was from fixed ELT activated on impact, it would transmit until it is destroyed or submerged
If it was a portable ELT activated by cabin crew, it would transmit until it is destroyed or submerged
One thought I have, without any new technology, airlines should instruct cabin crew to turn portable ELT on at the first sign of trouble,ie., don't wait for the crash they can later call airline and give all clear, if everything is a OK. This works only if CC member can reach it, big if.
Bottomline there is no way to estimate the duration of transmission. Like I posted upthread, even though aircraft may have 3xELT,8xRaft Beacons and 2xULB all are useless.
Last edited by notapilot15; 31st May 2016 at 23:25.