Little things to know about plane black boxes

On each aircraft there are two devices to store flight data and cockpit recording. As a focal point to determine the cause of each aviation accident, they are designed to be durable, painted orange (but still called the black box) and can self-signal position.

The Brazilian Air Force found the relatively intact black box of the Boeing 737 crashing into the Amazon on September 29, 2006, killing all 154 people on board.Photos: Wikipedia.

Since the Wright brothers, two pioneers in aircraft manufacturing in the early 20th century, they knew how to use a device to record the rotor's rotation. But it was not until the post-World War II period that the use of recording devices and flight data was popularly used and that they were commonly referred to as black boxes.

Since the 1960s, magnetic tape technology has been used to manufacture aircraft black boxes and is still in use today. However, modern aircraft are turning to solid-state technology (the solid-state) that has appeared since the 1990s with outstanding durability and efficiency. Today black box manufacturers have also terminated the use of magnetic tape. According to Honeywell Black Box manufacturer, solid-state storage technology is much more reliable than magnetic tape.

On the plane, there are two devices called black boxes including the Cockpit Recorder (CVR) and the Flight Data Recorder (FDR). In fact, they are painted orange in order to be most noticeable. Both operate from a power source from a generator that generates electricity from an aircraft engine.

Cockpit recorder (CVR)

All commercial airplanes today have cockpit microphones, to record all communications and communications of the crew. The microphones are also designed to catch all the other noises in the cockpit, like the sound of a switch, knocking on the door . Usually each aircraft cockpit has four microphones attached to the captain's headset, the headphones pilot pilots, third party crew members' headsets and mounts in the cockpit center, where the alarm signals and other sounds can be recorded.

Each microphone connects directly to the CVR black box. All sounds in the cockpit are recorded by these microphones and transferred to the CVR, where encryption and storage are carried out. Most CVRs use tape technology that can record 30 minutes of audio, when all is recorded again. So they always record the last 30 minutes of exchange in the cockpit before the accident happens. Meanwhile, the CVR black box uses solid-state technology that can record up to 2 hours of sound.

The robotic arms of the remote control search device are holding the black box CVR of the McDonnell Doughlas Md-83 of Alaska Airlines crashing into the Pacific on January 31, 2000, killing 88 people.Photo: Electronics.

Flight data recorder (FDR)

The second black box on this aircraft is designed to record a lot of operating data from aircraft operating systems. There are electronic sensors that are connected from multiple locations on the plane to the flight data acquisition device. From here the data continues to be transferred to the black FDR storage box. Any switch on the aircraft that is turned on or off is also recorded by FDR.

In the United States, the country's non-Federal Administration (FAA) regulates commercial aircraft to record at least 11 to 29 flight parameters depending on the passenger size of the aircraft. FDR black boxes using tape technology can record up to 100 parameters, while FDR using solid-state technology can record more than 700 parameters. Solid-state technology can store more parameters because they allow data to be transmitted faster. Solid FDR can store up to 25 hours of flight data and each parameter allows investigators to have additional clues to determine the cause of the accident.

Since 1997, the US Federal Aviation Administration regulates the FDR black box of aircraft manufactured after August 19, 2002 to score at least 88 parameters. The main parameters of the flight that most FDRs must record include flight time, pressure, cruising speed, vertical acceleration, location of wing parts and fuel flow.

The flight flight black box (FDR) of Egypt Air crashed into the Atlantic Ocean on October 31, 1999, killing all 217 people on board.Photo: Electronics.

Super durable design

In many aircraft crashes, the only active device is the core of two black boxes designed to resist extreme impact (CSMU). CSMU has cylinders placed inside black boxes. This is the intact part even though the other parts of the black box are damaged in the accident because they are designed to withstand extreme temperatures and pressures of tons. In older black boxes using magnetic tape technology, the CSMU core is usually placed in a rectangular box.

To ensure the black box durability, the manufacturer must conduct a particularly thorough test of the CSMU core unit. If investigators have this in their hands they will get back the information they need. The manufacturer's tests for the black box core are usually a very strong impact test like a real accident, a fire test, a deep submerged seabed test or immersion in a chemical with a high chemical . Normally black boxes can withstand temperatures as high as 1,100 degrees Celsius for 30 minutes continuously and soak in depths of up to 6,100 meters in 30 days.

Black box manufacturers often sell their products directly to aircraft manufacturers to carry out installation on aircraft. Both black boxes are placed on the tail of the aircraft, in order to increase their survivability in each crash. According to experts, the tail of the aircraft is usually the last position to be impacted when an accident occurs so it is the part with the highest safety.

Design a black box using solid technology.Photo: Electronics.

Find black box after accident

Although called black boxes, they are actually painted bright orange in order to be most noticeable. In addition, they are equipped with underwater position indicator lights (ULB). When the plane crashed into the sea or river or lake, this signaling device sent out an ultrasonic wave that the human ear could not hear, but the sound or ultrasound underwater positioning system easily detected them. .

There is a flooded sensor attached to this signaling device that looks like a bull's eye. When water hits this sensor, it immediately activates the signaling device to operate. Each signaling device is capable of transmitting ultrasonic waves once a second and continuously for 30 days. This is the time for teams to search for black boxes to use them to identify them, before they become useless. That's why the team looking for the black box of Air France's Airbus A330 crashed into the Atlantic on the night of May 31 is racing against time.

In the US, when investigators find black boxes they will transfer them to the National Transport Safety Agency (NTSB) laboratory. Experts here will have measures and equipment to ensure two black boxes are not damaged further. If the plane crashed into the sea and the black box was soaked in water, they would be placed in the chiller to keep the moisture in place, avoiding the drying of the black box affecting the data inside.

Experts will then proceed to download data from two black boxes to reproduce the situations and conditions on the plane when an accident occurs. This process usually takes several weeks or months to complete. It may take only a few minutes to read the necessary data if the black box condition is good, especially the type using solid-state technology. Black box manufacturers often provide investigators with a black box reading system and the necessary software to analyze data taken from them.

Both cockpit recording and flight data are invaluable for the investigation of the cause of aircraft accidents. These are often the only things that survive in each tragedy and provide an important clue to investigators. With the development of technology, black boxes will continue to play a key role in future aviation accident investigations.

Today, black boxes are used not only in airplanes but also on trains and cars. The new US automaker has filed for bankruptcy. GM has applied black box technology in its products like Corvette for a decade, to help police investigate when an accident occurs.