New FDR Decode

reply to post by turbofan


Turbo, I am not going to argue with you. The FDR records a serial bit stream from the DAU, but what you are talking about is not the signal I am talking about. I am talking about the the voltage stream (a binary representation of data collected by the DAU) sent to the FDR. It sends the logic value to the FDR and has absolutely nothing to do with what you just posted (other than transferring the binary values).

You don't have to get all techy and embarrass yourself. Just show me a logic value of 1 for this parameter so that we know it was recording.

Originally posted by 911files
I am talking about the the voltage stream (a binary representation of data collected by the DAU) sent to the FDR. It sends the logic value to the FDR and has absolutely nothing to do with what you just posted (other than transferring the binary values).

Voltage stream? You know there can only be one voltage level on the
wire at any given time...correct?

What signal are you talking about? THere is one from the door switch circuit
to the input of the DAU

The other is the serial stream from the DAU to the FDR.

Please clarify.

You don't have to get all techy and embarrass yourself. Just show me a logic value of 1 for this parameter so that we know it was recording.

I already posted a chart proving the door was part of the data polling.
Any item not scanned would have been listed as "Spare".

reply to post by tomk52

While your use of "baby" and "kid" were certainly uhh... "mature," I've been meaning to ask what exactly "Nyquist" scanning of a [nearly always ANALOG in about every context that I have seen] signal actually has to do with a DFDR (Digital Flight Data Recorder) and its datastream.

I would expect the relevant FDAU to actually be a DFDAU (Digital Flight Data Acquisition Unit) as well in a Boeing 757-200, after the 1997 FAA mandate.

www.boeing.com...

www.honeywell.com...

www.boeing.com...

Digital data streams are usually sent in blocks or sectors (but Boeing seems to prefer the word "frame"):

www.boeing.com...

While it has been mildly-"gossipy" hearing [off-topic] about your's and Will's resumes, all this Nyquist-Shannon business that you brought up back about 4 pages ago couldn't have been one of these could it?

en.wikipedia.org...

Does anyone know whether UA 93's data ever showed the flight deck door open please ?

Originally posted by turbofan
What signal are you talking about? THere is one from the door switch circuit to the input of the DAU

The other is the serial stream from the DAU to the FDR.

Please clarify.

Okay, I was very clear, the serial bt stream. Thanks for confirming you have no idea what you are talking about.

Please note you are posting materials from the the 757-3 frame. I did the same, why? Because this was NOT a parameter recorded in the 757-1, 757-2 frames. If you will refer to the Boeing frame layouts again, 4/21/97 was the date this frame was put into use. The plane, N644AA was manufactured in 1991.

Please show me the frame from 1991 that includes this parameter or evidence that it was upgraded to frame 757-3. Or show me a simple single value of where a binary 1 was recorded in the 42 hour record.

[atsimg]http://files.abovetopsecret.com/images/member/e92a5f5002e3.jpg[/atsimg]

I thought I'd save you some digging and post the frame history for you.

[edit on 28-11-2009 by 911files]

If you will look at the 757-3 frame where it lists the parameter, you'll see it was added in revision A2 of 757-3, dated 7/11/97.

[edit on 28-11-2009 by 911files]

Originally posted by Alfie1

Does anyone know whether UA 93's data ever showed the flight deck door open please ?

Warren S. didn't release any new UA93 decoder that I'm aware of, and that would be off-topic for this AA77 DFDR decode discussion.

There is an older UA93 decoder program at his webpage, but I haven't used it- I would recommend contacting the author:

www.warrenstutt.com...

Originally posted by turbofan

Originally posted by PilgrumAren't you talking about actual air pressure versus rate of change of air pressure?

No, not exactly.

Look at it this way, the Pressure Altimeter [PA] reads altitude based on the
plane's vertical position at any given time.

Sloppy & therefore wrong. The altimeter reads the static pressure, which is the best APPROXIMATION available to the true freestream static pressure.

The altimeter then converts this static pressure into a Pressure Altitude reading, which is a pretty good approximation to it's actual pressure altitude.

Originally posted by turbofan
If the aircrafts drops altitude,
over that one second of time PA will update with a new value. PA does
not tell you the time required to change altitude (rate of descent/ascent).

This is where VSI comes into play. VSI does not tell you the altitude, but
it tells you the rate of change in feet/min. By looking at VSI, you can calculate
the amount of change in altitude based on the previous scan.

No pilot calculates his altitude by performing a "running integration of the VSI" in his head.
You look at the altimeter. That's what it's there for.

Originally posted by turbofan
Even though VSI samples the pitot port, the static port is used to determine
the delta in pressure (which is also read by the PA absolute pressure sensor).

Are you REALLY sure that "the VSI samples the pitot port"?

You want to stand by this statement?

Do you really know how a VSI works? Or are you just faking it?

Originally posted by turbofan
As I mentioned before, I would expect to see these values "locked" in
their trends, and therefore would confirm Pressure Altitude whether it
were a 'real' file, or fabricated by flight sim.

They are tied together. They are just NOT "equal to" each other. They are tied in very specific ways that neither you, nor Robby, have yet figured out.

Robby posted before that s = 1/2 a t^2.
where s = distance, a = acceleration & t = time.

Robby's equation is wrong in the general case. (Or is only right for an initial velocity equal to zero. Which was not true in the case Robby was attempting to solve. As cesura tried to explain to him.)

The correct general equation is that
s = (Vi t) + (1/2 a t^2)
where Vi = the velocity at the beginning of the interval, and the other variables are as before.

Another relationship is:
Vf = Vi + a t
where Vf = the final velocity & Vi = the initial velocity

Another is
Vavg = (p2 - p1)/(t2 - t1)
where Vavg = the average velocity over that interval, and p2 & p1 represent the starting & ending position (or height) values.

Another is:
Aavg = (V2 - V1)/(t2 - t1)
where Aavg is the average acceleration over an interval, and the other values are as before.

These equations define how the various values are tied together. They are NOT "equal to each other". Or whatever you mean by "reflect each other".

The fact is that the values in the FDR file are logical & self-consistent.
There are round-off errors and instantaneous values not reflecting the full intervals. These are not a problem when you are differentiating to get velocities from positions, or accelerations from velocities.

However, you have to be careful. The round off errors and integration constants become sources of large accumulated errors when you try to integrate from acceleration to velocity or from velocity to position.

TomK

Originally posted by rhunter
reply to post by tomk52

 

While your use of "baby" and "kid" were certainly uhh... "mature,"

It wasn't intended to be mature.
It was intended to be effective.
And to stop the crappola.

It was intended to be a gentle whack upside the head to remind an obviously young kid (even if he is about 30) that it ain't smart to get snarky with people whose level of experience he is utterly unaware of.

Originally posted by rhunter
I've been meaning to ask what exactly "Nyquist" scanning of a [nearly always ANALOG in about every context that I have seen] signal actually has to do with a DFDR (Digital Flight Data Recorder) and its datastream.

Well then, why don't you ask.

And you'll find the answer back about 5 pages when the whole issue first came up.

And it was brought up in the context of mapping the 1 sample per second OUTPUT of the FDR onto the ANALOG profile of the terrain height in order to figure out where the plane was at any given sampling. And consequently, what level of resolution of the ground profile that one could get from one sample every 700 - 800 ft.

Now, speaking of "red herrings", all the rest of this wouldn't fall into that category, would it?

Originally posted by rhunter
I would expect the relevant FDAU to actually be a DFDAU (Digital Flight Data Acquisition Unit) as well in a Boeing 757-200, after the 1997 FAA mandate.

www.boeing.com...

www.honeywell.com...

www.boeing.com...

Digital data streams are usually sent in blocks or sectors (but Boeing seems to prefer the word "frame"):

www.boeing.com...

While it has been mildly-"gossipy" hearing [off-topic] about your's and Will's resumes, all this Nyquist-Shannon business that you brought up back about 4 pages ago couldn't have been one of these could it?

en.wikipedia.org...

Nahhhh...


TomK

Originally posted by tomk52

Originally posted by rhunter
reply to post by tomk52

 

While your use of "baby" and "kid" were certainly uhh... "mature,"

It wasn't intended to be mature.
It was intended to be effective.
And to stop the crappola.

It was intended to be a gentle whack upside the head to remind an obviously young kid (even if he is about 30) that it ain't smart to get snarky with people whose level of experience he is utterly unaware of.

Oh, I had guessed that you might be trying to remove any doubt that you are likely a pompous ass. I surmised that most astute readers could have discerned that already from this post of yours. Yes, yes, you're "the bestest MechE, you're the bestest EE, you're just the overall bestest in the world, tomfk!"

Does your ego feel better now?

BTW, on that "level of experience utterly unaware of" thing- you aren't even close on your wild speculations Tom.

Well then, why don't you ask.

Uh, I did- very subtly- you somewhat even answered the question, but I did have to page back several pages. I'm still not convinced of the relevance, however.

Now, speaking of "red herrings", all the rest of this wouldn't fall into that category, would it?

Nope, 60-80% of those links involve Boeing 757-200 aircraft (you know, as in DFDR, as in decode, with percentage depending upon the "options").- perhaps you should have read them. That last Wiki link involved red herrings and relevance, and you appear to have missed the point there in its entirety.

Have a nice life "KingE, Tomk the Bestest"

-rh

A couple of points.

1. Those who claim there are 11 other flights of the door condition closed have not provided any proof of their claim.

2. The claimed data for the "11 other flights" has not been verified by the data provided by the NTSB as was the flight mentioned in the original post. The "11 other flights" data will truly be exclusively from some guy in Australia, if ever provided. This data is unconfirmed and has never been verified. If ever verified, the data sensing door closed position does not mean default. See Turbofans post on previous page.

3. Date of aircraft vs date of regulation. Aircraft go through many changes over their lifetime to upgrade/update with regulation changes. They are inspected through what is called A, B, C, and D checks. The D check practically pulls the entire aircraft apart for inspection. If the regulation was required in 1997 for the FLT DECK DOOR parameter, it would be upgraded during the next inspection. The FLT DECK DOOR sensor and recording was required equipment on Sept 11, 2001 for the 757.

4. The sensor records either logic 0 (closed) or logic 1 (open). Those who claim logic 0 is a default value are wrong. Again, Turbofan explained this well in his diagrams.

Don't let keyboard commandos who have an extreme bias for the govt story cloud the issue (as is most likely their intention as this issue is very damaging to the govt story). Demand verified evidence for their claims.

[edit on 28-11-2009 by R_Mackey]

Originally posted by R_Mackey
A couple of points.

1. Those who claim there are 11 other flights of the door condition closed have not provided any proof of their claim.

2. The claimed data for the "11 other flights" has not been verified by the data provided by the NTSB as was the flight mentioned in the original post. The "11 other flights" data will truly be exclusively from some guy in Australia, if ever provided. This data is unconfirmed and has never been verified. If ever verified, the data sensing door closed position does not mean default. See Turbofans post on previous page.

3. Date of aircraft vs date of regulation. Aircraft go through many changes over their lifetime to upgrade/update with regulation changes. They are inspected through what is called A, B, C, and D checks. The D check practically pulls the entire aircraft apart for inspection. If the regulation was required in 1997 for the FLT DECK DOOR parameter, it would be upgraded during the next inspection. The FLT DECK DOOR sensor and recording was required equipment on Sept 11, 2001 for the 757.

4. The sensor records either logic 0 (closed) or logic 1 (open). Those who claim logic 0 is a default value are wrong. Again, Turbofan explained this well in his diagrams.

Don't let keyboard commandos who have an extreme bias for the govt story cloud the issue (as is most likely their intention as this issue is very damaging to the govt story). Demand verified evidence for th

Check and mate....you lose. No one needs to take my word or yours. I suggest everyone just download the Warren software and look for themselves. Find just one case in 42 hours of flight where the door was OPEN. You can't because the WORD has nothing stored in it except the default 0.

Didn’t we come to the conclusion a missile hit the pentagon. Now we’re back to a plane? Good cuz I’d still like to know why…

1. The people that where on the plane that supposedly hit the pentagon haven’t been seen since.

2. Where’s the wreckage? Isn’t that why we said missile?

3. Unfortunately I think the door thing can be blown off as a malfunction or any easy excuse. If we can’t explain the lack of any plane wreckage why do we have to explain a malfunctioning door sensor? Also, it would be possible for some one, especially in a hurry, to open a door have two people pass through and close it in a few seconds. Try it.

4. Are we now convinced there was a plane?

Oh boy, I don’t think I can start on the whole door thing.

I hope I'm not muddying the waters further here but I checked the parameters (working & not) recorded by the Allied Signal FDR on UA93 and the flight deck door door is not among them. That FDR appears to be a less sophisticated (older technology) design than the Loral Fairchild F2100 unit on AA77.

Considering the planes were of similar vintage, could it be that AA77 had an FDR capable of recording a parameter that wasn't actually wired into that particular plane? If that input was simply tied to ground it would produce the input (0) that was recorded. It was listed as 'not working or unconfirmed' along with a vast number of other parameters in the NTSB study dated Jan 31 2002.

Originally posted by Pilgrum
I hope I'm not muddying the waters further here but I checked the parameters (working & not) recorded by the Allied Signal FDR on UA93 and the flight deck door door is not among them. That FDR appears to be a less sophisticated (older technology) design than the Loral Fairchild F2100 unit on AA77.

Considering the planes were of similar vintage, could it be that AA77 had an FDR capable of recording a parameter that wasn't actually wired into that particular plane? If that input was simply tied to ground it would produce the input (0) that was recorded. It was listed as 'not working or unconfirmed' along with a vast number of other parameters in the NTSB study dated Jan 31 2002.

Not a 'muddying' question at all. A frame has a fixed amount of binary space associated with it. There is always room built in for adding additional parameters for future use. That is the case here. That particular WORD in the frame would just hold a binary 0 until some parameter(s) was assigned at a later date. The frame layout determines what parameters are stored in a paticular binary location.

[edit on 28-11-2009 by 911files]

Originally posted by Pilgrum
I hope I'm not muddying the waters further here but I checked the parameters (working & not) recorded by the Allied Signal FDR on UA93 and the flight deck door door is not among them. That FDR appears to be a less sophisticated (older technology) design than the Loral Fairchild F2100 unit on AA77.

Considering the planes were of similar vintage, could it be that AA77 had an FDR capable of recording a parameter that wasn't actually wired into that particular plane? If that input was simply tied to ground it would produce the input (0) that was recorded. It was listed as 'not working or unconfirmed' along with a vast number of other parameters in the NTSB study dated Jan 31 2002.

That's interesting. According to R-Mackey above :- " The FLT DECK DOOR sensor and recording was required equipment on Sept 11, 2001 for the 757." Your research indicates that UA 93 didn't even have a parameter for it, used or unused. Was it flouting requirements ?

Originally posted by Pilgrum
I hope I'm not muddying the waters further here but I checked the parameters (working & not) recorded by the Allied Signal FDR on UA93 and the flight deck door door is not among them.

Different FDR, different plane, different airline.

For example, United 757's have the door switch on the pedestal and it is a switch with a light when flipped (the door can be closed, but the light comes on when switch is moved to open position).

American 757's have the door switch on the overhead and is a button with an associated light when the door opens. (The light will remain off until the door is open, the door has a sensor itself).

There are many parameters which are all Logic 0 in the FDR data. Does that mean they are all "not working"? No. It means they are in that condition which record Logic 0.

The parameters which are "not working" show "#ERROR" throughout their column. Many parameters which are not required are just blank.

For instance, the "CTR_ENTRY_DOOR_R" is all Logic 0 for the entire flight as well. Does that mean no one used the entry door? No, it means the door is closed.

Conversely, "CTR_ENTRY_DOOR_L" shows Logic 0 and occasionally "#ERROR". This is clearly a faulty switch.

Logic 0 is not a default. It is a condition. The condition is CLOSED in the case of Door's.

Those who claim Logic 0 is a default also must believe all other parameters with all 0's may not be showing their true condition. This is faulty logic in and of itself and is used mainly by keyboard commandos who will attempt to find any excuse to hold onto their support of the govt story.

911Files, you should get some sleep. lol

Originally posted by Alfie1
That's interesting. According to R-Mackey above :- " The FLT DECK DOOR sensor and recording was required equipment on Sept 11, 2001 for the 757."

You need to familiarize yourself with a MEL. In other words, if it's on the plane, its required equipment (however, it can be deferred, but at that point mechanics come in and collar the breaker, in which case, the switch is completely open and the FDR will record #ERROR in that column as seen in other parameters). American 757's had/have a door sensor prior to 9/11 and after. Therefore, it's required equipment.

Originally posted by R_Mackey
911Files, you should get some sleep. lol

No, you should find us one case of the parameter being anything but the default 0 and documentation of a frame upgrade.

Just an additional FYI...
That #ERROR, that is generated by the software reading the parameter, not the value stored in the file. We are talking about a bit here. It stores just two values, 0 and 1.

[edit on 28-11-2009 by 911files]

reply to post by R_Mackey


A single bit binary data point has only 2 states by definition so, in the case of a simple digital indication, there's no 'error' or undefined state just simply open/shut, on/off or whatever the assigned point is monitoriing.

The 'ERROR' indication is generated by the decoding software and would indicate that the parameter was missing in that particular subframe or 'out of bounds' in the case of analog inputs or something along those lines.

911files beat me to it - I'm the one who needs sleep

[edit on 28/11/2009 by Pilgrum]

Originally posted by Pilgrum
911files beat me to it - I'm the one who needs sleep

[edit on 28/11/2009 by Pilgrum]

No, I was updating while you were writing. Didn't mean to steal your thunder, but you are correct.