AA77 FDR Data, Explained

Why are you building strawmen gravy? Please show me a post where I have mentioned the illuminati or lizard people.
 
WildCat said:
I like that line of thinking! So it's safe to say that the entire TRUTH movement is discredited.
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No the entire truth movement don't represent each other. James Meigs is the editor of popular mechanics and was caught lying. Hence PM is now discredited.
 
jessicarabbit said:
Why are you building strawmen gravy? Please show me a post where I have mentioned the illuminati or lizard people.
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- jessicarabbit/docker either bring something to the thread or go away

we need some help on some issues, this would be the first time you have really read a thread, you could, and you could help

your read all 10,000 pages of the NIST report, this thread should be a piece of cake
 
WildCat said:
What did he lie about?
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When asked about Chertoff being connected to the head of homeland security, Meigs claimed that Chertoff could not influence the project since he was a junior researcher. So Jeff rang and discovered that in fact Chertoff was the senior researcher.
 
jessicarabbit said:
The point of the call was that James Meigs had pretended Chertoff was a junior researcher on the 911 project. During the call he admitted he was in fact a senior researcher.

The call did its job beautifully.
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What does it matter, he's not related to Michael Chertoff. Get over it. Any other useless accusations?
 
jessicarabbit said:
When asked about Chertoff being connected to the head of homeland security, Meigs claimed that Chertoff could not influence the project since he was a junior researcher. So Jeff rang and discovered that in fact Chertoff was the senior researcher.
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Bulldung. The moniker of "senior researcher" was pinned on Chertoff by Christopher Bollyn, who called him, asked if he worked on the story, then asked him whether he was the "senior researcher." That title doesn't exist at Popular Mechanics, but Chertoff had been there longer than some of the others, and said something like "sure."

Meigs wouldn't have excused Chertoff's role as insignificant, especially not by implying that he is really related to the head of Homeland Security. I think you're simply lying here, but you're invited to prove me wrong.

ETA: the prank phone call was made well after Bollyn's article which called Chertoff "senior researcher."
 
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UnderTow said:
I don't know where this claim comes from and I have never stated such. But this paper is directed at 'them' and not 'me' so who knows. This Time value is there, therfore it was recorded. It's relation to real-world time before it was sync'd during the investigation is up for grabs.
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Correlating time between the FDR stamps and the "real world" is not easy. There is a specific error margin that this was done with, and that number is not in the public domain as best as I can tell. From my perspective, the number +/- 2 seconds I would say is an extremely safe guess, but the actual margin error is probably smaller.

Time sync within the plane is most definately very strict (microseconds?).
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Potentially nanoseconds. Hard to say w/o the datasheets of the components, though. It's fairly safe to say though that any time-error "within" the plane is insignificant compared with the rest. If the plane says two samples happened 1 seconds apart, that's good to alot of decimal places.

I don't know what claim is being referenced here either. But I find fault in suggesting that a parameter 'recorded' during one second (after Time.00) would be a value from Time-1.5 seconds.
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First, I've never said that, exactly. I state that if the frame starts at t=0, then the parameter is recorded some time between t=0 and t=1, and it was measured some time between t=-1 and t=1. (I also use the more conservative estimate of t=-0.5 to t=1, which would correspond to a "measurement" rate of twice the "recorded" rate.)

I don't see why you would disagree with this, unless you still deny the existance of the digital buffer (the so called parameter pool), and/or the reality that measured time does not equal recorded time. There is a 1 second window error (for 1Hz signals) in the recorded time. Furthermore, there is some delay between measurement and recording. For some samples (like reading an analog accelerometer), the second delay may be insignificant. For others, like computer airspeed, it is likely very significant.

The +-2seconds is also false for parameters that appear within the same frame/row of the CSV.
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It's not false when you take into account the digitial buffering error combined with the intraframe error of 1 second.

I still find this ridiculous within the scope of the parameters most concerned. Time,Accleration(s),Speed,Alititude, etc. If we are talking about unimportant parameters like a Seat Belt Light, well who cares. Every instance I have seen of Word location for the most crucial required parameters places them within the first 50 words. In our subject's 256wps frame this means these crucial mandatory parameters are recorded to FDR within .2 seconds of our .00 Time Stamp. For instance, TWA800's AirSpeed was located in Word 38. If this placement is similiar in AA77's Frame, AirSpeed would be recorded at +00.15 seconds.
But again, we don't know 'exactly' so there can be no real conclusion to any argument over this I suppose.
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You seem to be misunderstanding what "error range" is. Since you already agree that we don't know when a parameter is recorded inside of the 1 second frame, that means the error range between two parameters is 2 seconds. Altitude could be +0.0 and speed could be +1.0, or Alt. could be +1.0, and speed could be +0.0. Both are recorded in the same frame, and occur on the same line in the CSV file. The total difference is 2 seconds. That is _just_ using the recording time error. When combined with the digital buffering, that can be 3 seconds, or even 4 seconds in some cases.

1) The FDR will record data (or 'something') up until it is detached from all power. The CSV does not show the final 2 seconds other then a Time value. Whether partial data or no data occurs in the FDR we can't say. To say that the FDR stopped recording 2 seconds Before impact, error.
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This is mostly correct, and I thank you for pointing it out. Both you and I are using insufficiently precise language to describe what is happening. Frame :45 and :46 were partial frames, so for some parameters, the last recording happened in the :44 frame. That means that up to 2 full seconds for some parameters _is_ missing from the FDR. That was what I meant.

You are correct, however, when you state that the FDR itself was recording until the time of the crash. The data, however, wasn't necessarily valid up to that point, and for some parameters, up to 2 seconds of valid data is missing.

This is complicated by the fact that you need to add in the measurement-to-recording delay, to find the "age" of the final sample of any parameter.

2) Agreed on the first part in regards to the extreme hundreths of a second we keep talking about. The 2nd part I don't agree with but if he wants to say that s'okay I guess.
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There is no other reason to make this CSV file, other than to make it easy to plot in a program like gnuplot or excel. The actual FDR data with the frame descriptor is far more useful for any forsenic purpose. The FDR report mentions, specifically, that the CSV file is the source of the plots.

4) Except for those parameters which are recorded N per second.
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Well, again, we are both being too imprecise in our wording, but you are on the right track.

8) I only assume they're recorded during the same second. But to think that the Altitude and Speed Measument could differ by 2 seconds in plane time, I don't think so.
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Again, this is +1 second for frame haziness and +1 second for digital buffering. That provides a maximum upperbound of +2 seconds (and vice versa, giving a full error of +/-2 seconds, or a 4 second error range). Keep in mind this has to do with _two_ parameters in relation to each other. One might be 2 seconds ahead, or 2 seconds behind. Both would appear in the same line of the CSV file.



Overall, you seem to be 90% of the way there. The last 10% seems to be the fact that you refuse to believe that recorded time does not equal measured time. You seem to think that the delay between being measured and being recorded is safe to ignore. It's not. Once you accept the existance of this delay, and you go back and reread the footnote I keep bringing up, you will see how easy it is to explain how one parameter can "appear" to be older, but actually be much newer. That's because it was measured much closer to when it was recorded.

Finally, given your understanding as it is now, you can already debunk both of JDX's "lightpole" analyses on your own. He seems to think you are going to support his position. If you don't, then what do you support?
 
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I always liked this thread (not that I understand a word of it) because AS did such a fantastic job of presenting his evidence.

But what annoys me immensely is that Undertow (listed as a 'researcher' on the pilots for truth site) didn't have the common decency to concede or apologise to AS for all his bluster and arrogance at the start when he was subsequently found to be talking crap.
 
I was trying to ask some accident guys what the possible data missing was in seconds in a massive impact like flight 77. The data not recorded on the chip. The guy I am trying to ask would have some connections to Boeing. He never reads my email. He post tons to me, but I think his receipts are wholesale deleted with my requests.

Any updates from AS?
 
I think it's impossible for anyone to say with certainty how much data is missing except the people who actually looked at the recorder. I think the estimate in the 1-2 seconds range is probably accurate, though.
 
Anti-sophist said:
I think it's impossible for anyone to say with certainty how much data is missing except the people who actually looked at the recorder. I think the estimate in the 1-2 seconds range is probably accurate, though.
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I was looking for more to match the descent rate into the Pentagon. But if you mean 2 seconds past the time stamps; that gets real close to make me happy.

Dam CT guys drive me nuts.
 
beachnut said:
I was looking for more to match the descent rate into the Pentagon. But if you mean 2 seconds past the time stamps; that gets real close to make me happy.

Dam CT guys drive me nuts.
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I'm not sure what that mean, exactly. Are you talking about the absolute altimeter reading, or the descent rate in regards to the lightpoles?

In the first case, the speed + pressure is outside of the calibrated operating point of the altimeter. Those readings can't be trusted because they aren't calibrated for those conditions. In the second case, yes, the FDR is incapable of telling us with any precision where the plane was or how high it was relative to the impact point when it crossed over the lightpoles.
 
Anti-sophist said:
I'm not sure what that mean, exactly. Are you talking about the absolute altimeter reading, or the descent rate in regards to the lightpoles?

In the first case, the speed + pressure is outside of the calibrated operating point of the altimeter. Those readings can't be trusted because they aren't calibrated for those conditions. In the second case, yes, the FDR is incapable of telling us with any precision where the plane was or how high it was relative to the impact point when it crossed over the lightpoles.
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I was talking about how many data points are missing from the last altitude taken to the impact point.

If you assume the altitude is correct on the FDR. You can back off from the impact to that altitude. That could be 7 seconds back away from the Pentagon. Or about 4 seconds if you take the standard rate of descent the terrorist was getting during his final run.

I am still thinking about compressibitiy and the error on the altitude and airspeed. This guy is past the 350 KCAS limit on the airframe (or what ever the 757 limit is this is close).

Give me 4 plus missing seconds of altitude data to shut up the CT idiots; I will go look up compressabilty errors and see what the book answer is.

I know 77 hit the Pentagon; I am just pissed the CT guys keep adding 10 seconds to the clock!
 
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