Black box: how technology helps uncover plane crashes

When an air accident occurs, the investigation teams’ attention turns to a fundamental piece of equipment: the black box. Essential for unraveling the final moments of a flight, this technology is the key piece that allows authorities to reconstruct the sequence of events that led to the tragedy.

Despite the name, the equipment is not black. Its color is orange or bright red, tones chosen to make it easier to locate among the wreckage. The black box, in fact, is a set of two distinct devices, both generally installed in the tail of the plane, the part that tends to suffer the least damage in an impact.

What do black box recorders record?

The two components of the black box work together to provide a complete picture of the flight. Each has a specific and vital function for the post-accident analysis.

The first is the Flight Data Recorder (FDR). It monitors and stores hundreds of aircraft parameters. Information such as altitude, speed, direction, flap position, engine power and pilot commands are recorded continuously. This data allows you to create a detailed simulation of the plane’s behavior.

The second device is the Cabin Voice Recorder (CVR). Its function is to capture all audio from the cockpit. In modern digital systems, the default is to record the last two hours of the flight, although the time may vary depending on the equipment’s technology. This includes the conversations between pilotscommunications with the control tower, and any ambient sounds such as alarms or unusual noises in the aircraft structure.

Built to survive

To ensure information is recovered, recorders are designed to withstand extreme conditions. They withstand impact forces thousands of times greater than gravity, temperatures of more than 1,100°C for up to an hour and the immense pressure of deep water.

If the plane crashes into the sea an underwater locator attached to the black box is activated. It emits a pulse signal, or “ping,” every second for at least 30 days, allowing search teams to find it even miles underground. Joint analysis of FDR data and CVR audio offers investigators the chance to understand the causes of the accident and thus develop measures to prevent similar failures from happening again.