Originally Posted by
Cynical Sid
I don't see how it would help in this situation. You want as many people as possible to hear an emergency message. Systems of this type in any case do not work well when a signal is weak/noisy.
I have been flying for over 20 years now as an airline pilot. Never in those years have I heard a genuine emergency call on 121.5! However, several times EVERY week I hear ATC trying to call a lost-com-flight on guard in vain. Why? Most probably because the crew turned down or stopped monitoring 121.5 because of the constant useless chatter on it which interferes with the primary task of monitoring the active ATC frequency. If ATC would use SELCAL on 121.5 they would have a much bigger chance of getting in contact with them, because most probably they still have 121.5 selected in VHF 2 without monitoring it! Using SELCAL on 121.5 would definitely help in many of those cases! I fly over central Europe almost every day, and believe me, constantly monitoring 121.5 has become practically impossible!!!