American flight attendant revealed the meaning of the dual signal on board the aircraft 
American Airlines employee Tommy Cimato, who became famous on social networks videos about the profession, revealed the secret meaning of sound signals for crew members on board. He shared this on his personal TikTok account.
The flight attendant explained that two signals (the first in a high tone, the second in a low tone) during the flight means an incoming phone call at the flight counter, or when the flight attendant from one part of the airliner is trying to contact a colleague who is in another sector of the aircraft.
Three continuous double beeps (high and low) indicate an emergency on board. A single alert (in one tone) indicates to the crew that some of the passengers need help. In this case, the person presses the flight attendant call button, which is located above his seat or on the service panel in the washroom.
Earlier in November, the same flight attendant named the most ridiculous questions he had ever heard on board. According to him, one day an economy class passenger asked him where business class travelers were flying. Another oddity is trying to ask a cabin crew member how many times he has flown an airplane in his entire life.