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

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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

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?

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?

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.

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.

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.