What is a “black box” and why is it not black

Milan Jevtic, an inspector in quality control at “Jat Tehnika”, has a unique job in Serbia – he is in charge of controlling the correctness of “black boxes” of planes that are serviced in the hangars of this company at Belgrade’s “Nikola Tesla” Airport.

On his desk, there are computers whose software enables the reading of data important not only for determining the cause of the accident, but also for checking the correctness of various systems on the plane, as well as for controlling the work of pilots.

“Black boxes”, of course, are not black, but are painted in orange to be more noticeable after the accident, and they are so named because of the “black” reason of existence – determining the cause of the plane crash and the death of the crew and passengers.

“Every passenger plane must have two ‘black boxes’ – one – one records the technical data of the flight, and the other a conversation in the cockpit, which means communication between pilots and flight control ‘through headphones’, ie radio, but also each another conversation that takes place in the cabin “, explains Jevtić.

Behind this expert, “Jat tehnika” is a great experience. He enrolled in aviation high school in 1970, later he completed specializations abroad, and during the last two decades he was in charge of “black boxes”.

While the story of the history of the introduction of “black boxes”, which have been the standard in civil aviation since the 1960s, shows various generations of these devices. Initially, the data was recorded on a special tape, later it was stored thanks to the development of electronics, and today the most important part of the “black box” is actually a flash memory protected in a small cylindrical steel housing. The first “black boxes” in the domestic aviation appeared with the introduction of the “caravel” type aircraft, that is, in parallel with the beginning of the era of jet passenger planes in the then “Jat”.

“Initially, basic flight data was recorded, and today’s devices record more than thirty parameters. The most modern ‘black boxes’, which record flight data, record the last 25 hours of flight, ie flights. The device that records the pilot’s communication with the flight control and the conversation in the cabin, keeps the sound recording for the last two hours “, explains Jevtić.

The “black boxes” are made so that they can withstand a fall from great heights, ie a force of 3,600 G and a temperature of up to 1,000 degrees Celsius. Each of them is also equipped with the ULB (Underwater locator beacon) device, which, in the event of a plane crash into the water, sends an acoustic signal that can be used for up to thirty days after the accident, at a depth of up to five kilometers. When the Malaysian “Boeing 777” disappeared over the Indian Ocean on March 8 this year, the teams searching for the wreck relied on this device. At one point, the appropriate acoustic signal was captured, but after a month had passed, and the depths were around the limit of five kilometers, it was soon lost, so this mystery has not been solved even today.

Both “black boxes” are located in the tail of the aircraft, experience has shown that this part of the structure is the least damaged in the crash, so the television footage from the crash site is mostly the tail (vertical and horizontal stabilizer) is the only recognizable part of the aircraft. The planes are also equipped with the ELT (Emergency Locator transmitter) device, which is automatically activated as soon as the plane starts to fall and sends data on its position via satellite.

As for the currently most recent accident in the air force, the downing of the Malaysian “Boeing 777” over Ukraine, the interlocutor of “Politika”, with the caveat that he can only talk about the case based on media reports, says that the found “black boxes” will certainly provide evidence of that tragedy.

“It will be possible to determine whether the crew followed the instructions for flying over that territory, what the flight control required of them and what they did. The ‘black boxes’ work while in a crashing plane they have power supply. Even in the event that the rocket hits the plane, it is possible that they worked for another second or two after that and recorded data that could contribute to shedding light on this tragedy “, says Jevtić.

Gallery

1 / 2 Photo: Shutterstock

Milan Jevtic, an inspector in quality control at “Jat Tehnika”, has a unique job in Serbia – he is in charge of controlling the correctness of “black boxes” of planes that are serviced in the hangars of this company at Belgrade’s “Nikola Tesla” Airport.

On his desk, there are computers whose software enables the reading of data important not only for determining the cause of the accident, but also for checking the correctness of various systems on the plane, as well as for controlling the work of pilots.

“Black boxes”, of course, are not black, but are painted in orange to be more noticeable after the accident, and they are so named because of the “black” reason of existence – determining the cause of the plane crash and the death of the crew and passengers.

“Every passenger plane must have two ‘black boxes’ – one – one records the technical data of the flight, and the other a conversation in the cockpit, which means communication between pilots and flight control ‘through headphones’, ie radio, but also each another conversation that takes place in the cabin “, explains Jevtić.

Behind this expert, “Jat tehnika” is a great experience. He enrolled in aviation high school in 1970, later he completed specializations abroad, and during the last two decades he was in charge of “black boxes”.

While the story of the history of the introduction of “black boxes”, which have been the standard in civil aviation since the 1960s, shows various generations of these devices. Initially, the data was recorded on a special tape, later it was stored thanks to the development of electronics, and today the most important part of the “black box” is actually a flash memory protected in a small cylindrical steel housing. The first “black boxes” in the domestic aviation appeared with the introduction of the “caravel” type aircraft, that is, in parallel with the beginning of the era of jet passenger planes in the then “Jat”.

“Initially, basic flight data was recorded, and today’s devices record more than thirty parameters. The most modern ‘black boxes’, which record flight data, record the last 25 hours of flight, ie flights. The device that records the pilot’s communication with the flight control and the conversation in the cabin, keeps the sound recording for the last two hours “, explains Jevtić.

The “black boxes” are made so that they can withstand a fall from great heights, ie a force of 3,600 G and a temperature of up to 1,000 degrees Celsius. Each of them is also equipped with the ULB (Underwater locator beacon) device, which, in the event of a plane crash into the water, sends an acoustic signal that can be used for up to thirty days after the accident, at a depth of up to five kilometers. When the Malaysian “Boeing 777” disappeared over the Indian Ocean on March 8 this year, the teams searching for the wreck relied on this device. At one point, the appropriate acoustic signal was captured, but after a month had passed, and the depths were around the limit of five kilometers, it was soon lost, so this mystery has not been solved even today.

Both “black boxes” are located in the tail of the aircraft, experience has shown that this part of the structure is the least damaged in the crash, so the television footage from the crash site is mostly the tail (vertical and horizontal stabilizer) is the only recognizable part of the aircraft. The planes are also equipped with the ELT (Emergency Locator transmitter) device, which is automatically activated as soon as the plane starts to fall and sends data on its position via satellite.

As for the currently most recent accident in the air force, the downing of the Malaysian “Boeing 777” over Ukraine, the interlocutor of “Politika”, with the caveat that he can only talk about the case based on media reports, says that the found “black boxes” will certainly provide evidence of that tragedy.

“It will be possible to determine whether the crew followed the instructions for flying over that territory, what the flight control required of them and what they did. The ‘black boxes’ work while in a crashing plane they have power supply. Even in the event that the rocket hits the plane, it is possible that they worked for another second or two after that and recorded data that could contribute to shedding light on this tragedy “, says Jevtić.

Gallery

1 / 2 Photo: Shutterstock