Black boxes – the importance of Black boxes in aviation

Recovering the Black box of a crashed flight in Brazil, 2006
Recovering the Black box of a crashed flight in Brazil, 2006 | Source

What is a Black box?

Lately we can hear a lot about a certain ‘Black box’ in the media, especially after the sudden and mysterious disappearance of the MH370 Malaysia Airlines on the 8th of March, 2014 and the terrible incident over Ukraine of the MH17 Malaysia Airlines on the 17th of July, 2014.

The Black box is a recorder equipment, which has to be carried compulsorily on each and every aircraft. In case of a catastrophe the contents of this box can be removed and examined, so the investigators might be able to completely hear and ‘relive’ the last few hours or minutes of the aircraft. This way they are able to find out the exact circumstances of the collision and the things leading up to it.

The inventor, Dr. Dave Warren with the prototype of the Black box
The inventor, Dr. Dave Warren with the prototype of the Black box | Source

Did you know?

Despite of its name, the Black box is orange. Originally it was designed to be black, but later the experts realised that it would be much easier to find it in extreme conditions, if its colour was much brighter and easily noticeable.

The significance of Black boxes

The first Black box was produced in 1957 by an Australian scientist, Dr. David Warren. He realised that some kind of recording equipment might be crucial in a plane crash investigation, when he was asked to reconstruct the circumstances of the crash of the world’s first passenger jet airliner, the Comet, in 1953.

The Black box itself consists of two parts: the cockpit voice recorder and the flight data recorder.

The cockpit voice recorder – despite of its name – is not located in the cockpit, but it is in the tail of the plane. This equipment not only records everything that the crew of the plane says, but monitors every sound that occurs within the cockpit area. So investigators are not only interested in any conversation between the pilots and the ground control, but they also have a keen ear for any sounds that are out of the ordinary (faulty engines, sudden warnings, any creaking, etc.). The most experienced investigators are even able to tell the exact speed and engine rpm just by listening to these sounds. This cockpit voice recorder records cockpit data on a two-hour loop, which means that only the last 2 hours of the communication is available, meanwhile older content is continuously overwritten by the newest information. Using these data, experts are able to determine the circumstances and the timing of different events, which is crucial in a plane crash investigation.

A 'Black' box in reality
A 'Black' box in reality | Source

On the other hand, the flight data recorder has an even bigger importance than the cockpit voice recorder, as it records all the main and essential operating functions of the plane like the time, the altitude, the direction, the speed, the air pressure within the plane, the fuel gauge, the movement of flaps on the wings, etc. With all these information the investigators are able to completely reconstruct the last hours of the airplane, including its exact movements and factors that might have led to its crash.

The Black box was designed so that it is able to withstand even the worst and most extreme conditions for a certain period of time. Its outer case is waterproof, withstands corrosion, can resist a fire of 1100°C for even 60 minutes (or a fire of 260°C for 10 hours) and it is still operative even in extreme weather conditions (-55°C to 70°C). The device can ‘survive’ a depth of 6100 metres in the ocean while still submitting a signal (the Underwater Locator Beacon /ULB/ - that is fitted onto the box – gets activated as soon as the recorder reaches the surface of the water). The device can record more than 24 hours of data.

Searching a Black box in the ocean
Searching a Black box in the ocean | Source

Problems with the Black boxes

The battery life of these Black boxes can lead to problems. Although batteries on certain aircrafts were updated to be able to transmit (ping) for 90 days (after the crash of the Air France 447 flight in 2009), most of the batteries in operation today (as of 2014) are still only able to transmit for only 30 days after the crash.

But even if the transmitter is operational and it is properly sending signals, it might be extremely hard to pick its ping up from a distance that is bigger than a mile. Also, the seabed can be very mountainous, therefore small sonar devices and unmanned submarines have to be used to recover it from water.

Additionally, in case a plane crashes into the ocean, one of its transmitters, the emergency locator transmitter (which transmits a distress signal on impact) will be useless, as these are unable to operate in water.

Recovering the wreckage of an aircraft and its Black box from the ocean in 2006
Recovering the wreckage of an aircraft and its Black box from the ocean in 2006 | Source

On the other hand, the recorded data on the equipment will remain intact, even if the battery is flat – but obviously, not being able to detect the signal of the transmitter will make it almost impossible to recover the Black box once the battery is dead (although magnetic detection is still possible, of course).

Another problem with Black boxes is their size. Despite the significance of these recorders, they are as big as two shoeboxes stuck together; therefore it is extremely hard to recover them once a plane crashes and submerges into the ocean.

Also, these boxes are made of aluminium, therefore they are very heavy compared to their size (10 kgs) – so a Black box weighs more than 20kgs. This means that in water the recorder sinks very quickly.

The future

Today’s technology tends to go in a direction that everything will be smaller and smaller. While this might not entirely be the case with Black boxes - as they are already small enough for a big aircraft -, they might become more compact in a sense that they will be able to record much more – some experts say even 500 hours of – data.

Additionally, since the mysterious disappearance of the Malaysian MH370 aircraft the public raised many concerns with Black boxes. Most of these concerns were already mentioned above, in the ‘Problems with the Black boxes’ section, but to sum it up, experts agree that these recorders are outdated, as they were barely changed in the last 50 years. They should be able to record more than 2 hours of cockpit communication, to transmit pings for the recovery teams for more than 30 days – even 90 days seems insufficient for an item of this importance -, and they must have a stronger signal that can be picked up from further distances, not only from within a mile.

What about you?

Do you feel safe on an airplane?

  • Yes, I always do. It is just as safe as driving a car.
  • No, I'm always horrified.
  • Never had a chance to fly before.
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© Copyright 2014, Zsofia Koszegi-Nagy (zsobig)

© 2014 Sophie

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Comments on this article 2 comments

zsobig profile image

zsobig 2 years ago from United Kingdom Author

Thank you gamerjimmy, I totally agree with you.

Meanwhile I was reading and researching about the future of Black boxes I had the feeling that this area is kind of a black spot in technology, as although the main idea and the importance of these devices is incredible, the main technology behind the box was barely changed in the past.

Nowadays, when we are already way past MB and GB, even TB sizes (even if this seemed impossible when we were still playing with games that fit onto a floppy disk) - and moreover (as you said) we can use the cloud technology in our everyday life as well, I can hardly believe there is still no available technology to completely upgrade this device.

Hopefully after the Malaysian airline-mystery there will be some changes pretty soon.

Thank you for your comment!


gamerjimmy23 profile image

gamerjimmy23 2 years ago from California

Thanks, I enjoyed your hub. Given 21st Century technology, why can't flight data be continuously uploaded to cloud storage? Meaning, why hasn't the black box been supplemented or replaced yet?

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