AA77 FDR Data, Explained

It's just a matter of time befire Cap'n Bob bans wstutt for finding 4 extra seconds of data on the FDR, data which clearly suports the "official theory" and not Cap'n Bob's idiotic flyover claim.

Shades of Russell Pickering and John Farmer.
 
It's just a matter of time befire Cap'n Bob bans wstutt for finding 4 extra seconds of data on the FDR, data which clearly suports the "official theory" and not Cap'n Bob's idiotic flyover claim.

Shades of Russell Pickering and John Farmer.

Do you suppose there's someone he can ban for the stupidity of tying a flyover hypothesis to data taken from a flight recorder found inside the Pentagon at the crash site? Whose fault was that, I wonder?
 
It's just a matter of time befire Cap'n Bob bans wstutt for finding 4 extra seconds of data on the FDR, data which clearly suports the "official theory" and not Cap'n Bob's idiotic flyover claim.

Shades of Russell Pickering and John Farmer.

I have been thinking along those lines as well. Bobby has however been quite nice to warren. Uncharacteristic and, IMHO, insincere.
 
Excuse my lack of background work in this. It's not been an interest before...

Can you guys tell me where on the plane the accelerometers are located?

Do they also provide roll, pitch & yaw accelerometer readings?

It's difficult for me to imagine any source that of a force that could really apply any sizable linear, lateral acceleration to the cg of the plane.


Tom
 
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Excuse my lack of background work in this. It's not been an interest before...

Can you guys tell me where on the plane the accelerometers are located?

Do they also provide roll, pitch & yaw accelerometer readings?

It's difficult for me to imagine any source that of a force that could really apply any sizable linear, lateral acceleration to the cg of the plane.


Tom
A big thunderstorm.
 
I have been thinking along those lines as well. Bobby has however been quite nice to warren. Uncharacteristic and, IMHO, insincere.
Some dictators get off on being nice to the people they have marked for execution. You can be certain that Cap'n Bob is not happy with Warren going off the reservation like that. Aldo's already demanded a loyalty oath.
 
You are right, the -1 g long accer, is like stopping, you would feel you full weight wanting to go forward. .3 take off is feeling .3 of your weight pushed back in the seat.

Yes, that is what it would feel like.

As fast as the plane was going, however, a quarter-second deceleration of 1g corresponds to a 1% loss of airspeed during that quarter-second. It's pegged, of course, so it's probably more than a 1% loss of airspeed. Maybe it was the collision with the Pentagon, but it seems to me that the collision with the construction trailer could have produced that much deceleration, and maybe the cumulative deceleration from clipping several light poles could have done it. That's from my back-of-the-envelope estimates; I'd like to see some real calculations.

Will
 
Yes, that is what it would feel like.

As fast as the plane was going, however, a quarter-second deceleration of 1g corresponds to a 1% loss of airspeed during that quarter-second. It's pegged, of course, so it's probably more than a 1% loss of airspeed. Maybe it was the collision with the Pentagon, but it seems to me that the collision with the construction trailer could have produced that much deceleration, and maybe the cumulative deceleration from clipping several light poles could have done it. That's from my back-of-the-envelope estimates; I'd like to see some real calculations.

Will
I agree, the trailer may be a source. The lamppost are made to fall down on impact, not sure they would do much unless they were ingested and the engine was upset; that is a noticeable bang and pop you can feel.


(from the p4t-truth-NAZI) The only file(s) we can argue are the files officially provided by the NTSB through FOIA which do not need special software for decode. I'm sure the reply we will get from ASAR's regarding your extra 4 seconds conflicting with the NTSB conclusions... is going to be along the lines of, "The NTSB did not decode the file, therefore it is unreliable."
Math is special; not used by p4t. Same for physics.

Balsamo is calling Warren's software special, and he is making predictions. BTW, the raw data Warren got was from the NTSB, and Warren's decode matches the NTSB work on all complete frames I have seen. Proves Warrens work is correct decode of the raw data where it decode the exact (within rounding error) values the NTSB obtained with the standard software. Make no mistake, the raw data is decodable and we can not only argue with this evidence it is real evidence that ruins Balsamo's moronic over flight delusions. (not to mention the FDR was found in the Pentagon, or the DNA) Is being a core member of p4t the badge of stupidity?

The p4t forum is not a free speech zone, so they will not be arguing the files Warren decoded from the actually FDR files obtained through the NTSB. The chief delusion cleric at p4t limits free speech, bans free thinkers, and is unable to use math and physics to understand the real world. He must have figured out the 57 foot reading from the FDR is the lower road on the overpass before the Pentagon ruining his failed conclusions. How do p4t believers and terrorists apologists wave their hands fast enough to erase the fact (real evidence) of the FDR being found in the Pentagon?
 
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Can you guys tell me where on the plane the accelerometers are located?

Do they also provide roll, pitch & yaw accelerometer readings?

It's difficult for me to imagine any source that of a force that could really apply any sizable linear, lateral acceleration to the cg of the plane.


Tom

It's a single three-axis accelerometer and it's strictly for use by the FDR. On the 757 as well as most other Boeings, it's located in the main landing gear wheel well, very near the CG.

ETA: There are 9 other accelerometers located in the Inertial Reference Units - those detect any movement along or about any axis. But I dont think the FDR will record the raw numbers from those accelerometers, though I could be wrong.
 
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Or the rudder, if I'm not mistaken?

Respectfully,
Myriad

Not in coordinated flight.

The best example being acrobatic pilots, doing complex, coordinated maneuvers (loops, barrel rolls, etc) with a glass of water sitting on the instrument panel ... won't spill a drop.

It's actually a pretty good way to learn how, when & how much rudder to use ... if you don't mind dumping water into absurdly expensive electronics boxes. :jaw-dropp

My point on this was that, if the accelerometers are not located at the c.g. of the plane, then the moment arm will cross-couple yaw rate & lateral velocity (and their accelerations).

Tom

PS. BTW, it seems pretty clear in the sims that have been put on Youtube, allegedly based on the FDR data, that the rudder inputs are happening, but not displayed. If you watch the rudder indicator, it never moves. Even tho the nose of the plane is, at times, wandering all over the sky.
 
It's a single three-axis accelerometer and it's strictly for use by the FDR. On the 757 as well as most other Boeings, it's located in the main landing gear wheel well, very near the CG.

ETA: There are 9 other accelerometers located in the Inertial Reference Units - those detect any movement along or about any axis. But I dont think the FDR will record the raw numbers from those accelerometers, though I could be wrong.

Hey thanks, Ap.

What is your opinion of the causes of the last accelerations?

Tom
 
I will post the ver accer in a second.
...

These are the last 4 seconds of data with average G each 8 samples of G,
0.725
0.659
0.92
0.858
0.94
1.121
0.828
0.783 0.85425
...

Are these indexed to 1.000 G's?

In straight & level flight, do they read 1.00Gs or 0.00Gs?

Tom
 
Or the rudder, if I'm not mistaken?

Respectfully,
Myriad

Hey Bud,

You go tossing around terms like "respectfully", and they're gonna toss your butt outta here. "Conduct unbecoming ...", don't ya know.

With Ap's info (the accelerometers being very near the CG), then rudder pedal transients will not show up as lateral g's.

Viz, stomp right rudder. The plane pivots about a vertical axis thru the CG.

The nose of the plane slews to the right, and the pilots feel a lateral acceleration to the right.

The cheap seat goats in 3rd class at the back feel a lateral acceleration to the left.

Right over the CG, the lateral acceleration is zero. Due to the transient.

Now if the pilot holds right rudder (with wings level) so that he's skidding thru the air, he'll be presenting a lot of the left side of the plane to the wind, and he'll get a (relatively small) lateral velocity (not acceleration) to the right as well.

I'm pretty puzzled at that .56G lateral acceleration number. Given the mass of that plane, it's hard for me to imagine that even a compressor stall or the impact with the trailor is going to give that sort of number.

And I'm certain that they'd mount the accelerometer to withstand beaucoup G's. But perhaps if the bulkhead to which it was mounted was torquing around such that the accelerometers were no longer aligned with the axis of the plane. So that longitudinal accelerations were now showing up as lateral ones. One indicator of this might be a simultaneous decrease in the recorded longitudinal G's.

Or, equivalently, an impact vibration that "twanged" that bulkhead. Not moving the whole plane, but a vibration of the structure to which the accelerometer was mounted. This could make sense...

Does anyone yet have a fairly compelling idea of the time difference between the last data & impact?

Tom
 
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I'm pretty puzzled at that .56G lateral acceleration number. Given the mass of that plane, it's hard for me to imagine that even a compressor stall or the impact with the trailor is going to give that sort of number.

I'm under the impression that the starboard engine hit the construction trailer with a glancing blow with one end of the trailer, pushing that end of the trailer out of the way, rather than a direct head-on impact.

Given that there was a -.564 lateral acceleration, meaning a lateral movement to port, might that be consistent with a reaction to the glancing blow, i.e., a sudden lateral acceleration to the port as illustrated below, (Truck is yellow) given that the port-starboard axis of the engine mount is close to the port-starboard axis of the center of gravity? Or might we expect a different reaction at that force, like the engine shearing off?

OR, am I just whistling Dixie?

 
I'm under the impression that the starboard engine hit the construction trailer with a glancing blow with one end of the trailer, pushing that end of the trailer out of the way, rather than a direct head-on impact.

It does appear that way in photos.

Given that there was a -.564 lateral acceleration, meaning a lateral movement to port, might that be consistent with a reaction to the glancing blow, i.e., a sudden lateral acceleration to the port as illustrated below, (Truck is yellow) given that the port-starboard axis of the engine mount is close to the port-starboard axis of the center of gravity? Or might we expect a different reaction at that force, like the engine shearing off?

As has been pointed out above, it is essential to understand the difference between yaw and lateral acceleration, particularly since the accelerometers are located near CG. A glancing blow with that generator would produce some yaw moment, but, I don't think it would have been enough to produce more than half G laterally to the left. Certainly not enough to produce more than 1 negative G longitudinally.

If the eight engine was the one smoking in the video and it failed to produce thrust, the aircraft would yaw right and w/o correction would skid left causing negative accel. If that happened early enough there may have been time to record it. However, it's certainly debatable if an engine loss could have caused more than a negative G longitudinally. It would be noticeable, but how much?

If I'm not mistaken the left wing hit the foundation first. Was there enough time for that input and the longitudinal deaccel to be recorded in protected memory before loss of power? I have my doubts, but I'm not sure at all.

OR, am I just whistling Dixie?

Depends on which way your head is turned when you whistle!
 

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