Disassemble the aircraft black box and see which manufacturers' chips are inside[Copy link]
Today, I will show you the disassembly of the FA2100 cockpit voice recorder. Let me first explain the background. I found it at a garbage dump. I disassembled it for research purposes to see the internal structure. I didn't intend to record the process, I just took a few photos and looked up a lot of information. I am not familiar with circuits. If there are any mistakes in the following, please feel free to correct me.Before we begin, let’s answer two questions: Why is the black box orange? Why is it called a black box?Everyone can guess the color issue. Orange has higher recognition and is easier to find and locate. After all, it stores very important flight data.As for why it is called a black box, one widely accepted theory is that it is because the working principle is relatively simple. You only need to input data, and there is no way of knowing what happens inside. It is a bit like a "blind box."
Then some people will ask me if what I dismantled was dropped from a crashed plane →_→If it really fell from a crashed plane, then the black box should look like this at this moment:
So don't worry, this is a black box that has been retired normally.Next, let's do a little extra homework, otherwise the disassembly will be a bit confusing.There are two main black boxes on an airplane - the FDR and the CVR.
The upper part is FDR, the lower part is CVRFlight Data Recorder (FDR), generally called flight data recorder in Chinese, is a device that mainly records various parameter data of aircraft during flight. Generally speaking, the black box refers to FDR, which is the most important direct evidence in air crash investigation.Cockpit Voice Recorder (CVR) is generally translated into Chinese as cockpit voice recorder. In layman's terms, it is a recorder used to record radio calls, conversations between pilots and environmental sounds.It is a pity that what was dismantled this time was not the FDR but the CVR, so it looks rather simple.The CVR is mainly divided into three parts: FDAU, CSMU and positioning beacon.Flight Data Acquisition Unit (FDAU), which should be translated as flight data collection unit, is the base part with square edges, used to communicate with the aircraft-related data bus to obtain corresponding data and encode it.The Crash-Survivable Memory Unit, which should be called the accident data storage unit in Chinese, is the orange cylinder above. It is the place where data is actually stored. 70% of the weight of the entire black box is on it.Finally, the small cylinder fixed on the CSMU is an underwater locator device, which will automatically start and send out a positioning signal when it comes into contact with water.
After doing my homework, let's take a general look at the model we disassembled this time. This is a CVR from L-3 Communications, model FA2100. The appearance is as shown in the picture:
According to the design parameters of this CVR, its operating temperature can range from -55℃ to 70℃, and it can withstand:5000 pounds of pressure1100℃ continuous high temperature for one hourContinuous high temperature of 260℃ for ten hours3400G acceleration impactAnd no data will be lost. In general, it is a super powerful USB flash drive!As for what’s inside, let’s open it!Start by removing the cover protecting the service port, then the surrounding screws securing the CVR itself.Remove all the screws, tighten them one by one, without any panic.
At the end of the disassembly, I found that I needed to remove the CSMU first before continuing to remove the top cover of the FDAU, so I unscrewed the four huge bolts, lifted it vertically, and removed the connecting cable to remove the entire CSMU.
I only have ordinary precision tools at home, not wrenches of this size, so I had to use a lot of strength to remove it, and my hands hurt so much. The first thing I saw after removing it was two TI DSPs, which I will leave aside for a while and continue disassembling.
Lift the top cover and put it aside, remove the screws that fix the PCB, and you can take out the entire bottom plate. The whole board looks dirty, but it is actually quite clean. It has been glued all over, but it looks more like some kind of resin. As for the reason for gluing, I think you should know it without me saying it!There are still a few boards left in the interface part, so continue to remove the other half...
There is something else on the other side of the power board, but it is basically power-related circuits. There is also a very cute toroidal transformer, which is not surprising considering that this thing can work with both 28V DC and 115V AC.
All boards, without exception, have been thoroughly glued and are basically not damaged by liquids. At the same time, connectors are used to connect the boards to facilitate maintenance and replacement.
Next is the highlight, dismantling the CSMU. Considering that the production date is at the end of the last century, it is more likely that solid-state recording is used.
After tearing off the shock-absorbing foam underneath, four large screws appeared, so it took a lot of effort to take them all out...There is a handwritten serial number on the small tail. It is the same as the one on the sticker. It must have been assembled and calibrated by hand. The level of care in special equipment is different.
Taking off the bottom cover, it is basically certain that this model uses solid-state media for recording. The surrounding area should be a heat-insulating layer and shock-absorbing material, and the black one on the top should also be, but the material seems to be different.I scratched it with my hand and felt that it was a mixture of asbestos and foam, very light. Its main function is heat insulation and shock absorption.
I have to say that this thing is much smaller than I thought. After taking it out, there is basically nothing inside that can be taken out, all black foam.
A lot of effort has been put into protecting this cylinder, which shows the importance of what's inside.Without saying anything, just use a screwdriver and unscrew all the screws on the cylinder. Then you can separate the top cover.
As expected, the interior is a multi-layer stacked structure, which is tightly fixed together by 4 pillars and screws.The left side is the main control, and the right side is the FLASH. Now it’s time for the free guessing game. Which company does the FLASH used in this black box come from?Reveal the answer:
Anyway, after all of them were dismantled and lined up, it was still quite spectacular.Judging from the date on the label, it should have been assembled in the 21st week of 1998, and the chip itself was produced in 1997. It is a pretty good SLC chip in Intel's product line.
In that era, being able to erase and write 10,000 times was considered a good level. The operating temperature ranges from 0℃ to 70℃, so it should be a wide-temperature chip.However, there is a 182℃ sticker on the top cover. Does it mean that when the internal temperature reaches 182℃, the data inside is very dangerous? I am not very clear.
Finally, I checked what the main control was. As I expected, it was a custom chip, so it seemed that it was basically impossible to reuse the entire module.Let's calculate the total capacity of the entire module. 8x15 is 120MB. If we record four 30-minute audios, it basically consumes 1MB per minute?
Finally, let’s go back to this picture. I won’t talk about the two TI chips in the middle. They should be used to process analog microphone signals. One chip is responsible for two channels. The two black chips in the upper left and lower right corners of the DSP should be the DRAM cache used by the DSP.The one with the sticker in the middle should be the main control of FDAU, which comes from QuickLogic. Its essence is similar to the FPGA used now. It is a highly customized ASIC, but its flexibility is not as high as FPGA. In my opinion, it is a specially made chip.In addition, there are several major chips manufactured by QuickLogic, which should apply a complete set of solutions.
I had considered buying a set of repair tools to read the information inside, but when I checked online, the cheapest quote was around 40,000 US dollars, so I thought I should just dismantle it.
This is the wreckage after disassembly. In fact, the structure of this thing itself is not very complicated. The impression it left on me is the solid materials and some detailed designs. I will try to get an FDR to disassemble it when I have the chance. The solid-state CVR is still a bit simpler.
Zhao Yutian posted on 2022-3-22 13:13 The probability is very high. Previously, the black box of a foreign aircraft was broken, and the data was finally restored normally
The Aviation Administration stipulates that the black box will not be damaged even at temperatures over 1,000 degrees Celsius, and will not be damaged by a collision of 1 to 2 tons.
The one from a certain airline, it seems the real reason will remain a mystery, because the data will definitely not be recovered in that kind of collision
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