Black boxes record important flight parameters

What Is the Black Box on an Airplane?

The black boxes are essential to investigators of an aviation accident. But what exactly are they, and what do they do?

Tobias Holm

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If you’ve ever taken a flight, were curious about flight incidents, or are simply part of pop-culture knowledge, you’ve heard of the black boxes. But what are the black boxes on an airplane?

The black boxes are flight recorders present on most commercial aircraft. It is a virtually indestructible device that records flight data, cockpit conversations, and anything else needed to understand an accident with an airplane. These devices have been vital in cementing air travel as the safest means of transportation in the world, and they continue to produce critical information needed in aviation safety.

In this article, we will break down this mysterious black box and why it is required on planes today.

What Is a Black Box?

Though the “black box” is a misnomer, the devices are actually orange. Its primary purpose is to record data on the flight in a specific algorithm. The data can then be accessed by the authorities who are investigating incidents and accidents that take place.

Because of the importance of this data, the black box is built to be tough and resilient. They are built to withstand direct impact to a solid wall at 466 miles per hour (750 km/h), can sustain in temperatures of about 2,012 degrees Fahrenheit (1,100 degrees Celsius) for one hour, can tolerate a 2.25-ton static load for five minutes, and tolerate water pressure of up to 19,700 feet (6,000 meters).

There are two black boxes in each aircraft
A flight data recorder (left) and a cockpit voice recorder (right). These are from Asiana Flight 214.

These boxes are painted orange and lined with strips of reflective tape to make them as easy to locate and identify as possible. The device also sends out signals through a locator beacon if the device is lost in the sea and can be found within a radius of 15 miles. Sonars can then pick up the beacon and help guide the recovery of the black boxes. Despite this, it still may take investigators a significant amount of time to find it.

The black box is made up of several different important parts. The largest part is the power supply, which charges the memory unit and underwater locator beacon. A flash memory chip is stored inside the memory unit, a thick crash-survivable case. Each of these recording devices can cost between $10,000 and $15,000.

What Is the Black Box Used For?

Now, each commercial aircraft has two types of recording devices. The first is the Flight Data Recorder (FDR). This device logs thousands of parameters from sensors and systems all over the aircraft, such as:

  • Heading
  • Altitude
  • Airspeed
  • Engine and exhaust temperature
  • Vertical acceleration
  • Fuel Flow

The second device is the Cockpit Voice Recorder (CVR), which saves audio from the pilots’ microphones and earphones. In addition, a microphone in the cockpit, usually located in the overhead panel, records audio from the entire cockpit environment. This saves both the dialogue between the pilots and the communications the pilots are having with Air Traffic Control.

For the authorities, the ultimate goal of the black boxes is to investigate accidents and incidents to prevent them in the future. When a plane crashes, the accident is usually shrouded in mystery - Especially if there are no survivors to report on the incident. After investigators find the black boxes, they bring them to a lab to download data from the recorders in an attempt to recreate the events.

Black boxes are actually orange
The black boxes are actually orange. That makes them easier to find in case of a crash.

Experts from the airline, airplane manufacturer, and National Transportation Safety Board (when in the USA) are brought in to study the data and create an accurate representation of the events. After a process that could take weeks to complete, the data is studied thoroughly to uncover exactly what happened; is this a one-time issue, or is it something more serious?

The information collected and investigated by these professionals has led to improvements in aircraft and flight training, recall of certain software, and provided answers to what led to the accidents. An example of this work is Air France Flight 447.


Air travel is one of the safest travel methods on the planet, and black boxes have been one of the most important tools to make this a reality. As technology continues to advance and air travel continues to rise, these devices continue to play a key role in the aviation world.

Also read:

Commercial Aviation

Tobias Holm Twitter

Founder of Planenerd, based in Denmark. Got a LEGO plane as a kid. Obsessed with aviation since. None of my friends want to talk about airplanes.