Final answer:
Cockpit voice recorders must continuously record from the time the aircraft's engines are started until they are shut down. These recorders capture all communication between the flight crew and other sounds in the cockpit, providing crucial information for accident investigations.
Step-by-step explanation:
In aviation, cockpit voice recorders (CVRs) must be continuously recording from the time an aircraft's engines are started until they are shut down. The purpose of CVRs is to capture all communication between the flight crew and any other sounds in the cockpit. This includes conversations, radio transmissions, alarms, and engine noise.
CVRs play a crucial role in accident investigations by providing valuable information about the sequence of events leading up to an incident or crash. They are designed to withstand extreme conditions and are often equipped with multiple redundancies to ensure the data is preserved even in the event of an accident.
For example, if there is an unexpected loss of communication with an aircraft and investigators need to understand what happened, they can listen to the CVR recording to gather information and analyze the situation.