Every time a foreign air crash movie, the captain honestly said that he got nothing. What the hell does this mean?

Distress signal is an international radio distress signal. This kind of signal is usually used by airplanes and ships to call for help in life-threatening emergencies. When sending signals, they must shout three times ("help, help, help") to avoid misunderstanding, confusion or noise interference.

As a distress signal, "Mayday" was created by an Englishman, Federick Stanley Mokford. 1923, senior radio reporter at Croydon airport. The airport asked him to put forward a simple word to all pilots and ground crew as an emergency distress signal. At that time, most of the flights at the airport were to and from Paris-Lebourt Day Airport, so he took the French word "venez m'aider" and changed it into the English word "Mayday" with similar pronunciation as a proposal.