English version

mayday in Telephone, telegraph topic

From Longman Dictionary of Contemporary Englishmaydaymay‧day /ˈmeɪdeɪ/ noun [singular]  TCTa radio signal used to ask for help when a ship or plane is in serious dangerSOS
Examples from the Corpus
maydaySend out a mayday, jump in and wait.The pilot sent out a mayday.We sent out a mayday, but your guess is as good as mine if anyone heard it.