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AA77 FDR Data, Explained

From JDX on colboard:
The AlliedSignal SSFDR and SSCVRs have performed flawlessly with 100% recovery and no errors in the data. In one particular investigation the NTSB started with a download of the SSFDR contents at 9:00 am and by 1:00 pm of that same afternoon a full animation of the final moments of the flight were available for review.
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If that is going to be the quality of the expected argument, stop wasting your time. You are arguing with strawmen.

I'd like to point out, simply, that my document is based entirely on misinterpreting the CSV file and the animation it is based on. No one claimed the FDR had errors. I only claimed that the CSV file is not the full FDR data, in the raw. I explained how the CSV differs from the FDR data.

I hope your arguments are of a higher quality than this tripe.
 
Also, UnderTow, it appears that JDX keeps refering to you as the "computer expert". What are your credentials that make you an expert in this particular field? Mine have been stated, so let's hear yours, as well.

Let me repeat, I won't judge your analysis based on your credentials. I'm a firm believer that analysis stands alone, apart from its creator.. and I will attack it, directly. That being said, JDX likes to quote you as his "computer expert" and I'm wondering why he thinks you are an expert.
 
I need to work on my post count here. :)

You report is tripe. It is so full of misunderstandings, misintterputations, and is total bloat. I can't believe your "waving it about as proof".
 
UnderTow said:
I need to work on my post count here. :)

You report is tripe. It is so full of misunderstandings, misintterputations, and is total bloat. I can't believe your "waving it about as proof".
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Saying it, and demostrating it are two very different actions. Talk is cheap. So far the only thing you've brought up is completely irrelevant and arguing with a point I didn't even make (the very definition of a strawman). That makes you 0 for 1 in even ADDRESSING my arguments, let alone contradicting them. Let me reiterate the main point, again, in plain English: My "report" never stated that the SSFDR data had errors.

I've worked with them enough to know that they are incredibly good at recording exactly what they are told to record, when they are told to record it.
 
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Anti-sophist said:
Also, UnderTow, it appears that JDX keeps refering to you as the "computer expert". What are your credentials that make you an expert in this particular field? JDX likes to quote you as his "computer expert" and I'm wondering why he thinks you are an expert.
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I don't know why. The term 'computer expert' certainly could mean just about anything these days. Most likely because through my other work he's found me to be very adept with technology.

Anti-sophist said:
Let me repeat, I won't judge your analysis based on your credentials. I'm a firm believer that analysis stands alone, apart from its creator.. and I will attack it, directly. Mine have been stated, so let's hear yours, as well.
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In like terms, I don't care about your credentials much either, and I don't see why you even put them in your report, since they are pretty loose and easily typed by anyone. Perhaps to add a bit of extra fluff to the report maybe. And since you won't judge me by mine, I feel no reason to state them.
 
Summary

1) The FDR did not record the final moments of Flight 77. There is up to 2 seconds missing.
2) The CSV file is not meant to be analyzed forensically, it is meant to be plotted.
3) The CSV data is not raw FDR data. It is not even serial bitstream data.
4) The CSV data is not meant to be broken down into 1/8th seconds and analyzed.
5) The CSV data, properly interpreted, says that there are N samples during this particular frame.
6) Without the frame description, we do not know when in a frame any one sample occurred.
7) Without the frame description, we have lost the measurement timestamps, so the time a particular word was recorded does not necessarily equate with when it was measured.
8) Given these time-shift errors, any mathematics that uses more than one data-point runs the risk of assuming that two numbers occurred at the same time, when they didn’t.
9) Many of these errors can be corrected, greatly, with the frame descriptor.
10) Any analysis must account for (or justify ignoring) these issues in order to draw any valid conclusions.[/quote]

It looks like it would take more experts on the FDR to figure out how much time after :44 there is before impact.

The plane at :44 recorded data appears to be making another pitch down, pushing the nose down, and show signs of 6000 feet per minute descent again. He could have pushed too hard and then had to level off just in time to hit the posts and then there is just a second before impact in the Pentagon.

It would only take a six degree glide path to hit the ground in 3 seconds from the last data stored if the altitude is 300 to 400 feet above the ground. We all fly with these planes landing at about 3 degrees or less before the final flare, but the fpm are in the 500 range not 6000. But even flaring from 6000 fpm is possible, but where would 6 degrees put 77 from the base of the pentagon at attitude, and why cant the wingtip vortices from the wing rip up the light poles?

Darn CT guys now I have to look at the poles on the ground.

The FDR fits, and puts 77 at the pentagon. Plus we see how bad a pilot this guy was, he had no steady turn. How ever the video some pilot put out remarks how the terrorist should have dived from 7000 feet! Do not fly with that idiot, he will be dangerous, the turn the terrorist did was too loose altitude, guess he did not realize he could not loose that much altitude cause the dam plane glides too well and it is hard to loose altitude when you are a rookie pilot.

So how many seconds do we have to account for so the CT pilots stop misleading people?

Looked up some stuff on FDR, it has to process and compress the data before it is place in storage.

The FDR data matches what happened that day, as backed up with radar witnesses, eye witnesses, and forensic evidence.
 
UnderTow said:
'cargo plane' is just jargon in certain circles for any aircraft carrying over X gross weight. Whether it's bodies, boxes, or booty doesn't make a difference. It's all cargo.
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I'd post the specific link. But I'm not allowed. But it is right below your question.
/whistle
 
UnderTow said:
I'd post the specific link. But I'm not allowed. But it is right below your question.
/whistle
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I'm not a mod, and don't speak for them, but I seriously doubt they will fault you for circumventing this particular rule of posting a link when being directly asked for one by Gravvy and being well within the spirit of the rules. You could just put _'s where the '.'s go.

I am not mod a though, so follow that advice at your risk :)
 
I only said that b/c Gravy posted a link to his post which is on this very same page, and my reply was the post directly below his. So in like I would've post the link directly to my post like he did. But instead I jabbed at my post limitation again and simple quoted myself. See :)
/post 17
 
For real!! :D

Figure2.1_1.jpg

Fig1_A717FrameFormat.jpg


Damn, and right at the end of the day. I'll let you all sauce on that. Gotta run. /thanks Admins :)
 
That's an excellent graphic, as it fits perfectly into my explaination of things. My report describes the DAU (or, in this case, DFDAU), asynchronous digital data, and the digital buffering (so-called parameter pool).

Please read the fine print at the bottom. You will notice striking similiarities to what they are saying and what I am saying. This graphic is litterally proving my point for me.

Where did you get it? Is it copyrighted? Can I reproduce it for my report?
 
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