Flight AA77 on 9/11: Real FDR Analysis: Frank Legge / Warren Stutt

Originally posted by Alfie1

Originally posted by backinblack
reply to post by Alfie1

 

Then you lambast the authors for being frank about " limited accuracy of available measurements "relative to this specific issue . Showing bias much ?

Bias?
The FIRST thing the report does is ASSUME an error in the data regarding the time..
They adjust the time to suit the flight path..Then work on from there..

I am not getting your point. Are you referring to the aircraft clock and official impact times ?

I don't see what the time has to do with the flightpath can you elaborate please ?

Are you for real??
They altered the times which changes the whole flight plan at least as far as altitude is concerned..
Mind you, the altitude readings are already open to question as even weed agrees..
So if this was an attempt to debunk the flyover scenario then it is an epic fail..

They have the times altered and can not accurately confirm altitude..
Maybe it's you that needs to fully read the report...

reply to post by backinblack


I still don't understand your point. Who "altered the times " ? The FDR recording ended when it ended. The last recording was at 9:37:52 according to the aircraft clock. This is 6 or 8 seconds different from the two official impact times. All the authors are saying is that they don't know whether the aircrafts clock was a few seconds out or the official impact times are a few seconds out. One must be because there are two. But what does this have to do with the flightpath ?

So far as radio height is concerned all we have had is an unsubstantiated allegation from turbofan that radio readings above about 200 knots may be incorrect. Against that we have a statement from John Bursill over at 9/11 Blogger ( I posted a link on the previous page saying " This paper from the perspective of someone who is qualified to fit and repair the LRRA system and the DFDR system, this is a good description of what is rational and probably from the raw data " ( John Bursill is a Licensed Aircraft Maintenance Engineer-Avionics ).

Let me ask you this. Supposing the last radio height of 4 feet was so far out that in actual fact the aircraft had sufficient altitude to clear the Pentagon why does the FDR show at exactly the same moment off the scale decelaration ( greater deceleration than the device is capable of recording ) far more severe than any landing ?
It doesn't make any sense that a pilot trying to fly over the Pentagon and get away as quickly as possible would attempt such a thing and, anyway, wouldn't be capable of it. The only thing that makes sense is impact.

reply to post by Alfie1

Let me ask you this. Supposing the last radio height of 4 feet was so far out that in actual fact the aircraft had sufficient altitude to clear the Pentagon why does the FDR show at exactly the same moment off the scale decelaration ( greater deceleration than the device is capable of recording ) far more severe than any landing ?

I question how they even got this new information after the Government departments tried for years but that aside, look at your comment..

off the scale decelaration ( greater deceleration than the device is capable of recording )

Really?? You say that and ask WHY we question the conclusion??
As I said and even sent you a quote, Weedwhacker confirms the device is not designed for the conditions it recorded this data in..

It's not a reputable report and I highly doubt it would stand up to peer review...

reply to post by backinblack


The information was obtained through FOIA requests as the authors say in the paper.

The fact that a device is used in circumstances beyond what it was strictly designed for is not proof that it will fail in those circumstances. You obviously just don't want to know about a Licensed Aircraft Maintenance Engineer-Avionics ( John Bursill ) finding the RADALT readings perfectly feasible. Go have a look on 9/11 Blogger. I did post a link on the previous page.

Originally posted by Alfie1
reply to post by backinblack

 

The information was obtained through FOIA requests as the authors say in the paper.
The fact that a device is used in circumstances beyond what it was strictly designed for is not proof that it will fail in those circumstances. You obviously just don't want to know about a Licensed Aircraft Maintenance Engineer-Avionics ( John Bursill ) finding the RADALT readings perfectly feasible. Go have a look on 9/11 Blogger. I did post a link on the previous page.

You do understand the difference between "perfectly feasable" and "accurate" right..??

Is it not also "perfectly feasable" that the altitude readings were consistently off by say 90'.??
That's not really a lot considering cruise altitude or allowing for errors caused due to the instruments being "outside" their accepted limits..

I don't believe the "fly over" theory but this report doesn't seem accurate enough to debunk it...

" Feasible " was my word. What the Avionics Engineer said, in part, over at 9/11 Blogger was " I have no reason to think that the Low Range Radio Altimeter would not be close to accurate enough for the paper's purpose as the angle to the horizontal is very small so the sampling rate is not so important."

This is from someone , as he says, " qualified to fit and repair LRRA systems ".

Against that all we have had is turbofan's unsubstantiated allegation that the radio alt. may be out when the aircraft speed is over 200 knots. He hasn't backed that up with any sources yet and I am not aware that turbo is " qualified to fit and repair LRRA systems"

You have suggested that the final radio height of 4' could be 90' out but you don't have any basis for that; it is just a figure you have plucked out of the air. Have you picked it because that would just be enough to clear the Pentagon. In the which case, I go back to my earlier question. How do you account for the fact that the final radio height was accompanied by deceleration so severe it exceeded the maximum possible for the FDR to record ?

reply to post by Alfie1


Well, I was hoping you would do some research and look for yourself. I don't know why I have to
continuously provide links for people...the same ones that just agree with something and have no
basis for their understanding.

Bursill fixes and installs stuff. He doesn't know how it works. I, on the other hand do.

I design and test this sort of equipment. Bursill diagnosis it, and installs it. Big difference.

Here's the MFG link:

avionics-support.com...

There's a reason for tracking to be maxed out @ 330 feet per second. It's a limitation of the processor and
how the RADAR returns function.

"AA77" was moving at over 780 feet per second. That's more than twice the design limits of the device.

The previous RAD ALT value in the data was close to 300 (273 I believe...sorry, I can't check I'm at work).

The following is 4 feet (again, as I recall).

Pressure Altitude must be considered and it does not support an impact.

Forward acceleration does not change pressure altitude.

Forward acceleration does however effect the accuracy of the LRA-900.

These are facts, not opinion and they are supported by manufacturer links.

Originally posted by Alfie1


" Feasible " was my word. What the Avionics Engineer said, in part, over at 9/11 Blogger was " I have no reason to think that the Low Range Radio Altimeter would not be close to accurate enough for the paper's purpose as the angle to the horizontal is very small so the sampling rate is not so important."

This is from someone , as he says, " qualified to fit and repair LRRA systems ".

Against that all we have had is turbofan's unsubstantiated allegation that the radio alt. may be out when the aircraft speed is over 200 knots. He hasn't backed that up with any sources yet and I am not aware that turbo is " qualified to fit and repair LRRA systems"

You have suggested that the final radio height of 4' could be 90' out but you don't have any basis for that; it is just a figure you have plucked out of the air. Have you picked it because that would just be enough to clear the Pentagon. In the which case, I go back to my earlier question. How do you account for the fact that the final radio height was accompanied by deceleration so severe it exceeded the maximum possible for the FDR to record ?

It's time for you to look at this report for what it is..
A very biased opinion based on MANY asumptions from the authors..

reply to post by turbofan


turbo, I am not sure why you expect me to find sources to back up what you allege.

You say of the Avionics Engineer John Bursill that he " fixes and installs stuff, He doesn't know how it works ."
If I was John Bursill I would think that very arrogant and presumptive. Most people who fix and install stuff know how it works or they would be pretty rubbish at their job. John says " I have no reason to think that the Low Range Radio Altimeter would not be close to accurate enough for the papers purpose as the angle to the horizontal is very small so the sampling rate is not so important ". This indicates to me that John knows perfectly well how it works and he has referred to an aspect you haven't even mentioned.

I have looked at your link to description and specification and:-

(a) Was it an LRA-900 in AA 77 ? Pictures of the recovered FDR I have seen look different.

(b) I didn't see anything in the description or specs warning that the device would be inaccurate at speeds over 330 fps. Did I miss it somewhere ?

With regard to pressure altitude, the papers authors have gone to considerable trouble considering this, by reference to previous flights in the FDR to establish error. John Bursill says " LRRA is the best source of altitude below 2500 ft."

I know you want AA 77's altitude at the Pentagon to be sufficient to clear it so I will ask you the same question I asked another member. How come at the final moment, when radio alt. is recorded as 4', does the FDR record maximum deceleration that the device is capable of recording ?

reply to post by Alfie1

With regard to pressure altitude, the papers authors have gone to considerable trouble considering this, by reference to previous flights in the FDR to establish error. John Bursill says " LRRA is the best source of altitude below 2500 ft."

John Bursill is probably correct because the system was designed to measure altitude during landings..

Do you really think landing speed is over 400 knots???

Most instruments have "acceptable" limits..
In the fairness of true debate, would YOU care to list the acceptable limits of this instrument??

Or do you simply wish to accept the results as fact, disregarding what others have questioned?

Originally posted by backinblack
reply to post by Alfie1

 

With regard to pressure altitude, the papers authors have gone to considerable trouble considering this, by reference to previous flights in the FDR to establish error. John Bursill says " LRRA is the best source of altitude below 2500 ft."

John Bursill is probably correct because the system was designed to measure altitude during landings..

Do you really think landing speed is over 400 knots???

Most instruments have "acceptable" limits..
In the fairness of true debate, would YOU care to list the acceptable limits of this instrument??

Or do you simply wish to accept the results as fact, disregarding what others have questioned?

John Bursill is well aware we are talking about the last moments of AA 77 and not a normal landing. but he still thinks the radio readings would be " close to accurate enough for the papers purpose".

My take is that he thinks the readings could be thrown off a bit by excessive speed but not materially. i.e. 4' could not suddenly be 90' really to clear the Pentagon.

And, you still don't address the other issue, massive deceleration at that final moment.

Btw, it might interest you to know that John Bursill is a truther and member of AE 9/11t so there is a strong element of civil war going on here.

Originally posted by Alfie1You say of the Avionics Engineer John Bursill that he " fixes and installs stuff, He doesn't know how it works ."
If I was John Bursill I would think that very arrogant and presumptive.

John doesn't repair the LRRA itself. He simply replaces it. Like changing a tire.

I can guarantee that I know more about RF and RADAR being in the industry for over 17+ years (military + aerospace inclusive) that John, or yourself combined.

(a) Was it an LRA-900 in AA 77 ? Pictures of the recovered FDR I have seen look different.

A Radio Altimeter and Flight Data recorder are two separate items and pieces of electronics. I wouldn't
expect you to know that...just as much as I don't expect you to understand the the unit cannot function
accurate at more than twice it's design CAPABILITY.

(b) I didn't see anything in the description or specs warning that the device would be inaccurate at speeds over 330 fps. Did I miss it somewhere ?

Again, if you understood RADAR, you would clue into why it wouldn't work.

Think of a camera shutter speed designed to take photos of moving objects at 1000 frames per second.
At some point, if you are moving fast enough the image will become blurry.

Moving faster, the image becomes more useless and distorted.

Same thing with processors and RADAR. They are designed to function at limits.

Why wouldn't we spin tracking RADAR twice as fast according to your logic? We would be able to track
incoming objects better, don't you think? Hmmm...think about it. Read about RADAR. Think about the
camera shutter speed anaolgy.

With regard to pressure altitude, the papers authors have gone to considerable trouble considering this, by reference to previous flights in the FDR to establish error. John Bursill says " LRRA is the best source of altitude below 2500 ft."

Maybe if it were within limits.

FOr the same reason he cried about Pressure Altitude being "in error", the RADAR altimeter would be more
in error because it's effected by forward acceleration.

I know you want AA 77's altitude at the Pentagon to be sufficient to clear it so I will ask you the same question I asked another member. How come at the final moment, when radio alt. is recorded as 4', does the FDR record maximum deceleration that the device is capable of recording ?

Because the data is fake and likely recorded by a simulator.

reply to post by turbofan


turbo, I wondered how long it would be before a truther cried " fake data ". But isn't that what truthers always cry when the evidence gets tough ?

Can you provide any sort of qualified source to confirm that it is possible to fake an FDR ? As you know, AA 77's FDR contained not only the recordings from the final fatal flight but 11 previous flights amounting to more than 40 hours of flying. Millions and millions and millions of parameters recorded, some several times a second, and all must correlate.

Also, if the data is fake, why did it take FOIA requests to get hold of it ? And why did it take an independent New Zealand researcher in Australia to tease out the last few seconds of incomplete frames from the FDR which the NTSB didn't extract ?

reply to post by Alfie1


Already done.

Discussion on this forum about Fake FDR data. Just search it using my name as the Author.
You will find several links in my posts showing that Flight Sims have data recording capabilities
that produce the SAME DATA as their real world counterparts.

Afterall, the do use the same computers and avionics as a real jet.

I've also called a Level D Flight Sim company and recorded a phone call to prove Flight Sims can
produce flight data.



The audio drop outs are intentional to hide the identity of the school and associated airline.

reply to post by turbofan


I have just listened to 1/4 hr of your vid. You might point out to people that there is nothing about recording the flight sim until about 9 mins.

You just wasted the flight sim salesman's time didn't you ? How does this prove that you can simulate historic flights and match up exactly every detail and destination so that it comports precisely with radar and air traffic control?

Plus, you still haven't answered. If the data is fake, why did it take an FOIA request to get it and why did it take an independent researcher to tease out the last few seconds NTSB didn't bother with ?

reply to post by turbofan


turbo, I have thoroughly explaned this to you already....your allegation of the simulator versus the real airplane is seriously flawed. Perhaps I have failed to find just the exact words that explain it to YOU, and for YOU?

Already done.

Discussion on this forum about Fake FDR data. ......

Afterall, the do use the same computers and avionics as a real jet.

That is either intentionally disingenuous to claim (based on your stated +17 years of "experience" (experience that is somewhat useful, but only enough to give you a lot of false assumptions....gathered likely from reading the technical details). But as I've said, "book knowledge" is no substitute for practical experience in the specific field.

Now, if some part of your +17 years included ACTUALLY working with, designing or servicing Full Level-D flight simulators?? THEN you would be more qualified to make these assertions.

Furthermore...your little phone call to the company that offers (for a fee) an "experience" in a Full motion simulator suite is a red herring, as I've explained to you before. The salesman did NOT know your purpose, and your intent behind the questions you were asking. In order to sell his product, naturally understood your questions to mean "how realistic is the simulator" in comparison to the "real thing". (Assuming, as he did, that you were ignorant of many details of such devices).


NOW, specifically to using the same "computers and avionics"?

Here is the difference.....what is GIVING the inputs to those devices!!!! In a real airplane, they are receiving REAL data, from the various sources and equipment as appropriate. Compiled by sensors, converted as needed per the function of the component that uses it.

IN a simulator, it is ALL BINARY CODE!!

Let's look at your RA example....in the REAL airplane the transceiver measures, in real time, the ACTUAL terrain and obstructions beneath the antennas, as they pass over them. This information is converted to the various instruments, and fed to the other units that "look" at it.

In a simulator, the algorithms and computer coding determines the "airplane" position and altitude, all mathematically....and has NO BEARING on reality...there is nothing "physical"...no ground, no "obstructions"....only those simulants that are programmed in to the software.

SO......the Radar Altitude as "displayed" to the pilots when in a simulator is pure math, pure simulation. The INPUT to the actual displays is different...it is "number crunching", pure and simple.

Same with everything else....even to the "feel" of the controls. (The aileron and elevator "forces" on the control wheel, and the rudder pedal pressures required --- for engine-out work, and crosswind takeoffs/landings --- ALL supplied by hydraulics, FROM the simulator, to re-create what a "real" pilot on the "real" airplane will feel).

The real airplane does not need to "provide" those aerodynamic forces. Do not, however, be confused with what the "real" airplane DOES do, in terms of "artificial" elevator feel...this is a different concept, and is because the controls ARE hydraulically powered....so, at higher air speeds, the elevator "feel" is increased, to preclude over-controlling (think of the equivalent to your power steering on a car....and how the "feel" is speed-specific....).

reply to post by weedwhacker


weed, now you are here, have you any observation on the accuracy of a radio altimeter reading where the aircraft is travelling above 200 knots ?

I know as a pilot it is not strictly your field but it has been suggested on here you agree that would be inaccurate.

reply to post by Alfie1


I posted on that earlier.

In cases personally seen, below 2,500 AGL (that is only the limit of the DISPLAY in the cockpit. As seen in the specs, it actually CAN read up to 5,500 feet....and THAT range, "invisible" and "transparent" to the flight crew, is used for other purposes....part of the GPWS), and at max speed (in most country's airspace) of 250 knots, yes the RA reads properly. (Out in the "Air Mike" area....Micronesia....we have no airspeed restrictions in International airspace, over-water. Of course, there the RA is merely reading the ocean surface, and is flat, for all intents and purposes).

What is at issue, based on the manufacturer's stated accuracy and tolerances (of up to 330 fps ground speed), that is merely what the system is DESIGNED and GUARANTEED to provide accurate readings, unequivocally.

There is nothing at all in those technical specifications to suggest that the units CANNOT provide reasonable accuracy above those horizontal velocities. That is a red-herring fallacious argument.

You didn't understand the term "EMULATION" the first few times, so I don't expect you to be any smarter
this time around.

Here is the difference.....what is GIVING the inputs to those devices!!!! In a real airplane, they are receiving REAL data, from the various sources and equipment as appropriate. Compiled by sensors, converted as needed per the function of the component that uses it.

Gee Weed, guess what? The simulator is an airplane chopped off and put in hydraulic motion axis'.

It's all the same stuff, and if produces the SAME DATA OUTPUTS AND DISPLAYS!!!!!

IN a simulator, it is ALL BINARY CODE!!

And in A REAL 757 IT"S ALL BINARY CODE AS WELL!!!





That's what the FDR contains . BINARY DATA recieved from ELECTRONICS that produce BINARY DATA!

Gee, I just posted a damn video from a level D fight company that told you the DATA IS THE SAME!!!!



You are a pilot. I don' t expect you to understand how electronic devices function, or how emulation is
applied to make the Avition devices work as though you were in a real airplane.

I therefore don't expect you to debate this subject as you have ZERO experience with it.

Alfie,

Warren Stutt did nothing spectaular. He did what an honest technician at the NTSB refused to do, or
what the MFG software valued as "incomplete frames".

Warren is not smarter than the NTSB FDR tech. He is just more thorough perhaps.

Don't make it seem like there's any magic going on.

An FDR is just a big ol' USB drive, but it's memory module is encased in a very strong titanium frame
with highly sophisticated electronics to filter power and data.

reply to post by turbofan


turbo, you seem to be agreeing with me that Warren Stutt teased out the last few seconds from incomplete frames the NTSB didn't bother with. It really, really, doesn't sound like fake data to me.