- Shutterstock/Iryna Rasko
- Airplane black boxes play a key role in helping the aviation industry figure out why plane crashes occur.
- Black boxes have helped the FAA improve aviation safety standards since the 1950s.
- They contain vital information that can reveal why a plane may have crashed.
Every time a tragic aviation accident occurs, you’re likely to hear the news mention something about the hunt for the plane’s black boxes. These units are said to contain vital information that can reveal why a particular airplane might have crashed. Since the 1950s, the data inside black boxes has helped accident investigators, airline manufacturers, and aviation professionals improve flight safety for everyone. They are a significant contribution to airline safety, but have you ever wondered how they actually work?INSIDER found out some interesting facts about black boxes and how they record plane data.
“Black boxes” aren’t black at all.
- Kamenetskiy Konstantin/Shutterstock
They’re actually painted a loud, vibrant color called International Orange – a shade which is most often associated with San Francisco’s Golden Gate Bridge, or the colorful highlighters you used as a student. The purpose behind this is to make them highly visible in the event of an accident, since there can be a lot of debris.
Aviation industry professionals don’t actually call them black boxes.
As previously noted, the name “black boxes” is actually a misnomer, and it turns out, most people aren’t completely sure why the term is still used. Some sources say it’s because of its mysterious properties. Others say the name the name comes from the color of the box when its found after a crash, as it’s typically covered in ashes.
Whatever its origins may be, you likely won’t hear a professional referring to them by that name. Instead, they call them by their technical terms: Flight data recorders and cockpit voice recorders, or FDRs and CVRs.
They’re actually made of two components: the flight data recorder and cockpit voice recorder.
- REUTERS/Wolfgang Rattay
Technically there isn’t one single “black box” on each plane. Instead, there are two parts – the flight data recorder (FDR), and the cockpit voice recorder (CVR). During a flight, the FDR tracks information about the plane itself, like its direction and speed, while the CVR records audio of the crew’s conversations, radio transmissions, engine sounds, and alarm noises.
Sometimes they can be combined together in one unit, but they are often two separate devices. They’re also quite expensive to make. The standard flight data and cockpit voice recorder system can cost anywhere from $10,000 to $15,000 to produce.
Human error is one of the primary reasons black boxes exist and are still used today.
- Bruce Bennett/Getty
It’s true that inventions are born out of human necessity. In the 1950s, an Australian research scientist named David Warren helped to investigate the repeated plane crashes of the first commercial jet airliner, The Comet. He proposed that if researchers had knowledge of what happened on the plane moments before it went down, it would help them figure out how to improve the next flight.
While mechanical failure is a very real possibility, it’s been noted by several sources that the most common cause of airline crashes is pilot mistake. This is arguably why the CVR (cockpit voice recorder) exists, and not solely the flight data recorder.
Australia was the first country to make black boxes mandatory in its airplanes.
- Omar Prestwich/Unsplash
Initially, the Australian government expressed concerns about Warren’s invention interfering with pilot privacy.
After the fatal 1960 crash of Trans Australia Airlines Flight 538, authorities quickly changed their minds and required flight data recorders be placed on all commercial airlines. The United States followed suit three years later.
Information is stored on a memory chip inside a small portion of the device called the Crash Survivable Memory Unit (CSMU).
The original flight data recorders registered information on a magnetic tape. It wasn’t until many years and technological advancements later that they started recording with solid memory chips, which are used to this day.
Contemporary models of memory chips stay housed inside a titanium or steel portion of the unit called The Crash Survivable Memory Unit. This keeps the important data safe even if the recording devices themselves are totally burnt, crushed, or destroyed in a crash.
They typically hold 25 hours worth of flight data, like airspeed and altitude, but only two hours of audio recordings.
- Photo by Lian Jonkman on Unsplash
The cockpit voice recorder only registers the last two hours of audio and re-records over itself in a continuous loop. The plane’s flight data recorder, however, can store up to 25 hours of information about the plane’s position, speed, fuel levels, and more during a single flight.
This means that the standard FDR has enough data storage to cover even the entirety of the famous Singapore airlines route from Changi Airport to Newark Liberty Airport, aka the longest flight ever.
The flight data recorder is required to monitor a minimum of 88 different stats every second.
According to The National Transporation Safety Board, the flight data recorder can track up to 1,000 different parameters, including fuel levels, altitude, engine gauge, temperature, direction, and speed. The Federal Aviation Administration requires that a minimum of 88 possible parameters are tracked in a given second. Since 2008, all new planes are required to record 91.
The locations of black boxes can be traced in the bottom of deep oceans thanks to a special tracking component.
- Nieuwland Photography/Shutterstock
Every flight data recorder contains a tool called an underwater location beacon (ULB). This makes it possible for investigators to find it if a plane crashes into a body of water. Once underwater, it sends out an acoustic signal that searchers can detect with a special receiver.
Finding the FDR and CVR from a plane that’s crashed into an ocean can still be tricky. In order for the signal to be heard, one has to be within a 15-mile range of the beacon. On top of that, the battery life only lasts for 30 days after it’s been submerged.
However, it’s not impossible. Two years after the 1987 crash of South African Airways 295, investigators found the plane’s cockpit voice recorder 16,000 feet below the surface.
Black boxes are placed in the airplane’s tail because that’s where the least damage will occur.
Even though the CVR records cockpit audio, the recording device itself doesn’t sit up front with the pilots. Typically the pilot area is fitted with several microphones, but the actual device that stores the recordings is hidden in the tail of the plane. This prevents the FDR and CVR from being completely destroyed in a crash since the tail typically feels the impact last.
As Joe James of the Information School at The University of Washington said, “Planes rarely back into mountains.”
Airplane black boxes are extremely durable.
- Christopher Furlong/Getty Images
The Australian Transport Safety Bureau reports that flight data recorders can withstand fires up to 1,100 degrees Celsius and a continuous pressure force of 5,000 pounds for up to five minutes. In addition, they can endure water pressure at depths up to 20,000 feet.
However, they are not indestructible.
Many FDR and CVR have been totally destroyed by the physical impact of plane crashes. Recent news stories about the October Lion Air 610 Crash from this year have reported that the plane’s CSMU experienced water damage that could make it very difficult for investigators to handle.
Only a special committee is allowed to listen to black box data.
- Unsplash/Leio McLaren
Once an FDR or CVR has been recovered from a plane crash site, it gets transported to a special lab for analysis. After the data is extracted, a panel of exclusive aviation VIPs, everyone from industry experts, airplane manufacturers, and FAA officials, meet to review its contents. They then piece together the audio recordings and information from the FDR and try to deduce what happened in the moments leading up to an incident. The rules regarding who gets to be involved in the investigation are very strict and highly regulated by The US National Transportation Safety Board.
In fact, the US Congress explicitly forbids CVR audio recordings from being released to the public. They only publish the written transcript of the CVR data after the official safety hearing occurs.
To this day, some black boxes have never been recovered.
The unfortunate part about airplane black boxes is that they are pretty useless if investigators don’t physically find them. This is precisely why the causes behind several plane crashes over the past 60 years remain a mystery. The black boxes were either too damaged to extract any information, or they were simply never recovered.
The most recent incident where this happened was in the aftermath of the Malaysia Airlines flight 370 that crashed into the Indian Ocean back in 2014. Investigators and rescue teams have spent several years searching the ocean floor for the missing aircraft and its black boxes, but they have yet to find anything.
Throughout history, there have been several other flight black boxes that were never recovered, including the ones from two of the planes used in the September 11 attacks. As a result, some people have argued that it’s time to take a more live-streamed approach to recording flight data. However, some remain hesitant due to the cost of implementing such changes on an international level.
Visit INSIDER’s homepage for more.