Flight crews adhere to the "Sterile Cockpit Rule," a federal regulation (FAA 121.542) that prohibits non-essential conversation and activities during critical phases of flight, typically below 10,000 feet. This includes the entire process of taxiing, takeoff, and the final approach and landing. The rule was established in 1981 to prevent distractions after several accidents were traced back to "idle chatter" that led to a loss of situational awareness. During these times, the pilots must focus entirely on monitoring instruments, communicating with Air Traffic Control, and executing checklists. Similarly, cabin crew are trained to remain silent and perform a "30-second review," mentally rehearsing emergency procedures like exits and evacuations. This period of quiet ensures that if a technical anomaly or emergency occurs, the crew can react instantly without the cognitive delay caused by social interaction or unnecessary announcements.