Flight Data Recorder Basics - Part 1

Learn the basics of how data from a flight data recorder is interpreted for use by investigators and analysts. Part 1 of a 2 part series looking at the ARINC 717 format. Visit us at www.scaledanalytics.com.

[@ramsaini3745]

great explanation

[@robshef718]

Excellent presentation for the student, thanks.

[@siutubetube]

Thanks . Happy to learn that they are well protected. Is there any website I could find the statistics data is total lost , partly lost etc.

[@subinrevi1]

Greats video..well explained !

[@MrRBond007]

This was very well explained, thank you.

[@Scaledanalytics]

+BLACKWOLF Thanks for the feedback. Glad to see it's helpful.

[@user-wz1wj2br9x]

it's awesome ! i could understand Data Recoder basics !

[@Scaledanalytics]

Thanks for the comment. We're glad it made things easier to understand.

[@jamesscotney5820]

Can you explain the last bit for me? 2^12 = 4096 values (0 - 4095)? I understand that the 12 represents a word (at 12 bits). Is the 2 representative of the sample frequency i.e. 1Hz & 0.5Hz?

[@Scaledanalytics]

Hi, James. It just means that with 12 bits, you can have 4096 possible values. From 000000000000 (0) to 111111111111 (4095) and everything in between. The 2 represents the number of possible values of a particular bit (either a 0 or 1).

[@jamesscotney5820]

@@Scaledanalytics Thanks for the reply. What math are you applying to get 4096 values from 0's and 1's though? Sorry, I'm not too clued up on this.

[@Scaledanalytics]

@@jamesscotney5820 Hi, James. For every bit there are 2 possible values, zero or one. So with 12 bits there are 2 to the power of 12 possible values, or 4096. If there were only 2 bits, for example, there would only be 2x2 = 4 possible values: 00 (0), 01 (1), 10 (2) or 11 (3). If you are ever bored, the Windows calculator has a programmer mode that can be used to convert binary to decimal numbers (among others). Hope this helps.

[@siutubetube]

just wonder if the black boxes are well protected. impression : fragile... data always lost in crashes. or even .... cannot find them.

[@Scaledanalytics]

Thanks for the comment. The boxes are actually very well protected. Despite how severely damaged they may look on TV after a crash, the memory is normally well protected. We have an article on our website describing how data is typically recovered from damaged boxes --> www.scaledanalytics.com/2015/03/30/how-will-they-recover-data-from-that/.

[@djdrops22]

Thanks for great explanation. I have a question what is main difference between Arinc 573 and Arinc 717?

[@Scaledanalytics]

It's been (quite) a while, but I believe the older 573 standard was for the old magnetic tape-based recorders that used a Harvard Biphase pattern on magnetic tape to effectively create 1s and 0s. It was a pretty ingenious idea at the time and is worth a Google search if you're interested in some of the history of older Flight Data Recorders.

[@djdrops22]

@@Scaledanalytics Thank you very much for the reply.

[@user-hv4xn1lm6y]

Is there a reason why the frame is defined to 4 sub-frames each representing a second of flight data? It would be much more simple defining a frame for each second.

[@Scaledanalytics]

One of the advantages of having 4 separate sub-frames, rather than just one is that you can store more parameters that can be sampled at less than 1 Hz. For example, you can have something like Flap Position sampled once every two seconds, e.g. in Sub-frames 1 and 3, and Slat Position in the same words but in sub-frames 2 and 4. This lets you store 2 separate parameters in the same word location (rather than 1 if you only had a 1 second frame), but sampled at 0.5 Hz, rather than 1 Hz. I hope this helps and thanks for the question.

[@boz1944]

Cool Video :D

[@Jason_Quinn]

"one-based" indexing is making me cringe