Why does it take half a year to decode an airplane’s black box?

1.03K views

In light of the recent plane crash in Pakistan, reports suggest that it will take 6-7 months to decode the black box.
The company that made the black box surely knows how to decrypt their encryption, so why would it take so long?
Also, assuming the encyrption is super-complicated, what sensitive data would warrant such encryption? Is it just voice recordings, or something more?

In: Technology

20 Answers

Anonymous 0 Comments

Normally they are slightly damaged due to the conditions of the crash, then it isn’t the decoding that is a problem it is interpreting the data, the data tells you what happened and when but not all the other things that happened. So an engine failed at 11.03 20 seconds later the plane goes into a steep dive. Is it crashing or are the pilots trying to dive to restart the engine or even put out a fire?

Anonymous 0 Comments

Im no black box expert, but from what I know, it’s basically a log of all of the aircraft’s sensors and all of the things the pilots did. Imagine a massive excel file with hundreds of columns(vertical) . Each column is a sensor, be it altitude, aircraft nose angle, air speed, engine power, amount of fuel, door closed sensors, etc, anything you can imagine that an aircraft might have. Then every second, the value of all the sensors fills out a row(horizontal) in that excel file. Well, that’s a shitload of data, and looking through an hour or more of that pure data is going to take a lot of time. You’d be looking for abnormalities in sensor readings or weird combinations of sensor values, sensors that stop working, pilot actions that didn’t result in the expected sensor response, etc. It’s probably just a ton of crap to go through, and unless you find a real “smoking gun” figuring out what exactly happened would take a lot of time a knowledge of the entire aircraft. That make sense?

Anonymous 0 Comments

It’s probably inaccurate reporting.

Most likely they can read it right away, but it’s the full analysis what takes time. Sure, the black box says what each sensor reported, but what does that actually mean? Eg, did the black box record low fuel because there was too little to start with, or a sensor malfunctioned, or there was a leak, or some unexpected condition caused the airplane to burn fuel faster than normal?

They may need to collect all the wreckage and look at the remaining bits, and interview survivors.

They have to be careful with these things, and make sure not to blame the wrong thing just because that can cause additional harm.

Anonymous 0 Comments

No expert, but decode in this sense doesn’t mean it’s encrypted for security reasons and they’re thinking “oh shit, we forgot the password” it’s more to do with the complexity of the task at hand.

It is also extremely important to make sure all the data is correct and none of it is corrupted (bear in mind, this box went through a hell of an impact) and if something is reading the wrong figure, it could screw up the whole investigation. So they have to error check and back up (safely) millions of lines of code reporting everything that happened, from thousands of sensors, millisecond by millisecond. Not an easy task.

Anonymous 0 Comments

AliHB brings up a good point. If the company that makes them can’t read them, how do they know they’re working? Why “invent” a way to read them after the fact? Whichever system they use to record the data, there should already be a user friendly system to read the data.

Anonymous 0 Comments

this is bad reporting. The FDR will be repaired and all the data will be pulled. it’s raw data, but from that they can build a pretty good picture of what was happening to the aircraft’s systems leading up to the crash. That data will be compared with crash data from other aircraft and compared with findings from air accident investigators who have examined the wreckage and any eye witnesses/survivors/video footage and the Cockpit Voice recorder which has all the pilot and copilot’s conversations right up until they die.

At the 6-7 month stage the press release will be “we’re pretty sure the plane crashed because of XYZ reasons”

Anonymous 0 Comments

Imagine someone’s car crashed and you want to understand what happened. You have a recording of the crash, but it’s not a video – it’s a recording of the exact speed each wheel was doing, what the brake pressure was, what the position of the accelerator was, the engine temperature, the air con setting, and so on.

You’d eventually be able to understand a lot about the crash, but you’d need an expert to look at all that data and tell you what it meant.

Now imagine that for an aeroplane except there are several hundred times more pieces of data to look at, and the ultimate cause of the crash may be buried deep in one obscure sensor reading. That’s what you’re ‘decoding’ with a black box.

Edit: thank you for the gold and awards! My first ever!

Anonymous 0 Comments

When people use the word decode in contexts like this, they’re talking about taking raw data, packed for efficient storage, and decoding it into a form that is understandable by humans, and then working out an interpretation of events.

Normally extracting the data is easy, but if the recorder is damaged, it could require specialized skills and tools to retrieve and decode.

Normally the vast majority of the time is just spent piecing together events, and making sure you got it right and every anomaly in the data is explained.

Anonymous 0 Comments

It depends on the type of aircraft and the operator but usually there are two “black boxes” — one is the CVR (cockpit voice recorder) and the other is the FDR (flight data recorder). The FDR records panel settings, alarms, fuel flow, and similar. If they are damaged in a crash it can be difficult to extract the information. Sometimes it requires the expertise of the regional transportation safety board and sometimes it even requires the original manufacturers to extract meaningful information. All of this needs to be methodically analyzed in an attempt to understand what happened leading up to, during, and sometimes even after a crash. Sometimes it’s obvious and sometimes its a major puzzle.

Anonymous 0 Comments

As others have mentioned, the analysis is the long part. But ensuring integrity of the data is a huge challenge as well. Plane crashes are violent affairs, and getting to the storage media, and getting the data off in a safe way is a forensics and computing nightmare.