Final answer:
The EMER/NORM switch on aircraft audio control panels allows pilots to alternate between normal and emergency communication modes to maintain contact with air traffic control during emergencies.
Step-by-step explanation:
The EMER/NORM switch found on audio control panels in aircraft typically serves an important function. Its purpose is to allow pilots to switch the aircraft's communication system between normal operations and emergency modes. In normal mode, pilots and crew can use the standard communication channels to talk with each other and with air traffic control. However, in the case where the standard communication system fails or there is an emergency, the switch can be flipped to the emergency position. This reroutes the audio to emergency channels, ensuring that the pilots can maintain communication with essential services, such as air traffic control, in order to relay the aircraft's emergency status and receive assistance.