What is the frequency designated for emergency communication?

The designated frequency for emergency communication in aviation is 121.75 MHz. This frequency is utilized for emergency situations by pilots and air traffic controllers. It serves as a universal emergency frequency recognized worldwide, making it crucial for communication during crises. It enables pilots to alert air traffic control and other aircraft in the vicinity about emergencies and request assistance.

The options provided that are not associated with standard emergency communication frequencies serve different purposes, such as specific air traffic control communications, but they do not hold the universal priority that 121.75 has during emergency situations. Understanding the importance of this frequency allows drivers and operators at O'Hare Airport to ensure their readiness for handling emergencies appropriately and effectively.