AA77 FDR Data, Explained

[BCR]

It is amazing the things people see in these videos.

 

[Baylor]

LOL. It's probably nothing, just the loop gives it the illusion like something's happening when it's not. Oh well

 

[Jonnyclueless]

You're talking about the frames right after Elvis takes a sip from a cherry slurpie right?

 

[Cobalt]

You're talking about the frames right after Elvis takes a sip from a cherry slurpie right?

After that he bums a cigarette off Jimmy Hoffa.

Well done on all the work by AW and 911files.

 

[bje]

911files,

If this helps with reference topography, using my GIS software, this is the line-of-sight view starting at 2500 feet from impact point, along the flight path of AA77.

The profile at bottom shows a very specific view. It is the view from zero altitude, i.e., eyes right on the ground, to the impact point, assumed to be 10 feet above ground.

It only shows the topography altitude, not man-made structures nor vegetation. Therefore, where the flight path crosses the intersection bridge, it does not show the altitude of the bridge above the road below, but the altitude of the road below.

If you find this useful and I can do any kind of profile.

 

[A W Smith]

After that he bums a cigarette off Jimmy Hoffa.

Well done on all the work by AW and 911files.

I haven't done any work yet, I just quickly collected some googled data and i see my time is off by 3 minutes. I was using 9:37 not 9:40 .

what I am curious about is if you took a straight line from the impact hole and the damage path of the poles, the clipped tree, and the peg knocked off the VA dot camera pole. From a point just above and half the wingspan north of the plane from the VA dot radio tower top off Columbia pike. Would the altitude and azimuth line starting from the shadow intersect it?

another thing I was wondering was Paiks assumption that the repairs he witnessed the very next day to that VDOT radio tower were because the wing tip hit it. Now if CIT claims that Paik puts the plane north of Columbia pike at that point. Why would Paik assume the damage to that tower would even be possible? if it flew over his head (as CIT claim) it would need a 560 foot wing span

 

[BCR]

I was wondering was Paiks assumption that the repairs he witnessed the very next day to that VDOT radio tower were because the wing tip hit it. Now if CIT claims that Paik puts the plane north of Columbia pike at that point. Why would Paik assume the damage to that tower would even be possible? if it flew over his head (as CIT claim) it would need a 560 foot wing span

I'll take this one first. What CIT does not understand is that human beings are the worst estimators of position that you could possibly use to determine a path with. On September 10, 2008 I spent the day following up on interviews with the Arlington County Police officers and verifying what they observed. One block west of ACP Off Foust's location at Columbia Pike and Walter Reed, witnesses in a small shopping center also saw the plane.

Mr. Howison had just stepped outside and was talking to someone in the parking lot when the plane passed. According to him the plane flew straight down Columbia Pike over the middle-of-the-road! Obviously, the radar and RO2 track is several blocks south of him and witnesses only a block east have the plane on the south side of Columbia Pike. Mr. Howison is not lying, and is relating his PERCEPTION, which often can be quite different from reality.

Knowing the Sun's azimuth and elevation, the shadow cast by the plane as it passed the VDOT area if it were at ~310 feet, would appear on the ground at around 500 feet from the plane towards Paik's location. For anyone wanting to play with it in GE, the distance from the A-One Auto location to the VDOT tower area in the direction of the Sun that morning is a good fit. Both Paik brothers talk about the "dark" plane. Sound's like the plane's shadow passed over their location and it was passing between Paik and the Sun when he saw it. That makes a lot more sense than some other speculation I have heard regarding his account.

Might I add that this also agrees with Madelyn Zakhem's account:

Madelyn Zakhem, executive secretary at the STC, had just stepped outside for a break and was seated on a bench when she heard what she thought was a jet fighter directly overhead. It wasn't. It was an airliner coming straight up Columbia Pike at tree-top level. "It was huge! It was silver. It was low -- unbelievable! I could see the cockpit. I fell to the ground.... I was crying and scared," Zakhem recalls.

 

[jaydeehess]

I am noting the small flash at 9:40:37. Not the big one at 9:40:38 (-and a halfish), over a second later. 77 was going about 714 ft/s so that would put the plane around 1000' ft out, making it a good candidate for the small flash at :37 being the light poles getting struck. I'll break it down by the seconds.

9:40:35 - 77's shadow (not shown in this loop)
9:40:37 - small flash, possibly light poles getting struck.
9:40:38 - big flash, 77 hitting pentagon.

I if may suggest another possibility for the small flash on the tape and for what Morin saw;
a sunlight glint off the round, silver aircraft. (what part of the a/c, the height of the a/c, the exact angle of the fuselage to the sun in three dimensions, etc.) There are so many variables for such a reflection that it would be nigh on impossible to know where along the flight path tit occured and it would do so at a different time for Morin than for the Citgo camera.

However the lamp poles would probably arc as they were snapped off.

 

[BCR]

Looks good bje

 

[BCR]

I am curious about is if you took a straight line from the impact hole and the damage path of the poles, the clipped tree, and the peg knocked off the VA dot camera pole. From a point just above and half the wingspan north of the plane from the VA dot radio tower top off Columbia pike. Would the altitude and azimuth line starting from the shadow intersect it?

First, the plane did not fly a straight line. At some point, according to witnesses the plane did some banking, most likely to the port side. This looks like the most probable path in the vicinity of the VDOT, with a slight turn as it passed the area.

This is a simple projection based on the wingspan of the plane (~125 feet) of the DCA radar data. It is unknown exactly what point the plane initiated the port turn, and it is highly possible it made a series of minor banks and turns along the way (some witnesses report a starboard bank). So the means there is a range of possibilities for exactly where the plane flew past the Citgo (to the south). However, the shadow position is consistent with that range. More details on these path segments can be found at the links below.

DCA Path Extended
VDOT Update

These comments might be useful from someone who worked the scene extensively with the firefighters.

One of our suspicions with some of the light poles knocked down by Flight 77 was that maybe they were not directly struct, but the turbulence from a very large plane flying very low at 500+ mph might have generated enough force to knock many things down or loose. Hard to tell. Striking the first tower might have produced some of the smoke that was believed to be coming from somewhere on the plane, possible the right engine. I never believed there was enough time for something to get ingested into the engine and for it to produce smoke, if it was part of a light pole, it would have been less than a second. But striking the antenna might have done enough damage to cause it.

 

[bje]

What is the height of the lamp poles above ground?

 

[MacGyverS2000]

I only visit about once a month (when I receive an automated email from JREF telling me there has been more activity in this thread), so keep that in mind when replying to me. I glanced through about 4-5 pages of new material since my last visit, but I didn't read anything in much detail.

TF, I didn't waste my time cut-n-pasting all of your points (not did I receive a PM as you suggested in an earlier post), so I copied one of your posts on the fly and comment on each part here:

I'll wait for him to back up his statements with his real name instead of a faceless account.

Claiming the addition of my real name to this account would suddenly lend credibility to my previous analyses is a non sequitur, like my car having an extra 50 horsepower because I put a NOS sticker on the bumper. Not to mention the fact that you already claim to know my name from the same website you (indirectly) requested my help from. I use this same handle on many boards, so it doesn't take a rocket scientist to figure out my personal information... I chose not to post it here for no other reason than my fingers didn't type it in. Your handle is TurboFan, mine is MacGyverS2000... should I disregard whatever you say because you didn't use your real name?

It's a silly argument meant to do nothing more than deflect the simple fact that my assessment of the data does not agree with yours. Feel free to post my real name, I don't care, it's your keyboard time. But it won't change my analysis.

Until then, he has zero FDR experience and his theory no longer makes sense based on these points:

I don't recall ever claiming I was an expert on FDRs. If you need it in writing, fine. Here ye, here ye... let it be known the MacGyverS2000 has never (and never intends to), to the best of his knowledge, worked on an FDR! What I did claim was quite a bit of experience designing and programming for embedded flash systems. Do not mistake a lack of experience with in-the-field FDRs with a lack of experience with the subcircuits they're composed of... that's like saying I don't know how an electric burner works because I cook on a gas stove. You think FDRs are the only thing that requires transient/surge protection? You think they're the only thing that uses flash as a data backup?

- a transient on a data line, or address line cannot issue an erase process

I've covered this already... if you don't agree with me, that's not my problem.

- EEPROM requires DC voltage over a sustained duration to reset gates, as opposed to a few milliseconds of noise

I've covered this already... if you don't agree with me, that's not my problem.

- The gates require a minimum DC voltage to reset. As power decays this voltage is no longer sufficient.

I've covered this already... if you don't agree with me, that's not my problem.

Gates cannot be reset by impact force, it's done electrically.

Does this really need to be said? Like cars require a fuel source to run... obvious and unnecessary to point out.

- The firmware determines which address lines are enabled and when the write/erase occurs. It is an involved and complex set of instructions - not a single 'switch' feature.

Yes, and when the hardware is operating under within operating limits. Obviously power transients, shorted lines, etc. remove this essential assumption. I've covered this already... if you don't agree with me, that's not my problem.




As to a debate...

Isn't that what's already happening here? You make it sound like a Sunday night WWE match at the Coliseum. If your friend wants to add in his two cents I have no objection. If you want to start a new thread that pertains just to the flash, I have no objection (in fact, I asked for such a thread earlier). But if such a thread is started, I won't rehash what I've already stated. My prose here can be quoted directly, in full, and moved over by someone else. Should there be a question not covered in that text, I'm happy to debate it.

But your feeble attempts to bait me into a pissing match are going to fail miserably... you had better come at me with something real, not these half-assed ad hominem logical fallacies you seem so keen on using. You don't like my answers, that's your problem. As Rush sings, you can twist perceptions, but reality won't budge. Don't think you can make this personal to me with the perception I'll waste my time revamping what I've already typed. My real name is irrelevant to the facts, and even if it wasn't you still couldn't use it against me as it's easy enough to find, just go to the eng-tips.com website and look up the same handle. It even has a link to my LED business.

You have provided zero new evidence to discount my possible scenarios (and that's what they are, possible scenarios for flash corruption, exactly what you originally asked for).

 

[BCR]

Ouch...how do you say "ripped a new one" on JREF without getting banned?

 

[Turbofan]

Your handle is TurboFan, mine is MacGyverS2000... should I disregard whatever you say because you didn't use your real name?

I'm not an electrical engineer. Those who will be signing up here to debate
will use their real name. I just might throw mine in for good measure.

My experts will not come here to debate a faceless account and anyone
with enough expertise to make claims about a system should very well
offer a name for reference purposes.

Do not mistake a lack of experience with in-the-field FDRs with a lack of experience with the subcircuits they're composed of... that's like saying I don't know how an electric burner works because I cook on a gas stove. You think FDRs are the only thing that requires transient/surge protection? You think they're the only thing that uses flash as a data backup?

Do any of your flash drives, memory devices, or designs require certification
for commerical aviation use? Do they also consider thousands of g impact
force to protect the data by way of physical damage and production of
transient from impact?

You have provided zero new evidence to discount my possible scenarios (and that's what they are, possible scenarios for flash corruption, exactly what you originally asked for).

[/QUOTE]

As mentioned before, I'm not the one who will be debating your points.
I don't know the systems as well as the engineers who disagree with
the statements made here that a transient could initiate an erase command
and wipe out previously recorded data.

We can get into the write/erase process and the requirements for each to
occur (mainly with the erase function). More to the point, that a DC voltage
must be applied to the gate in order to change the bit state.

I've measuried transients on digital transmission lines (not avionics) and noticed
that the duration of the peaks (non filtered) is a few milliseconds at best.

Couple this with a fast decay of available/useable power and the theory
of transient erasure falls flat.

Correct me if I'm wrong, but your transient theory assumes that an erase function
was already in process, or starting in order to make sense?

In other words, the FDR was not writing flight data at this time.

 

[WildCat]

I'll take this one first. What CIT does not understand is that human beings are the worst estimators of position that you could possibly use to determine a path with.

An incident at the Bears-Jaguars game yesterday afternoon is a good illustration of this. On the Jaguars first offensive series of the game, the QB threw an interception directly to the Bears' Danieal Manning. Manning ran it back, but fumbled near the sideline at the 5 yard line, the ball bounced out of bounds. The referee, who was right on the sideline within a few yards of the play, ruled that the ball had hit the pylon and by rule this would be a touchback and the Jaguars would get the ball back at the 20 yard line.

But then they showed the replay, which showed conclusively that the ball did not hit the pylon, it had rolled out at the 1 yard line. It was actually a Jaguar player that hit the pylon. Bears coach Lovie Smith threw out the challenge flag, and upon further review the call was reversed and the Bears got it at the 5 yard line, the spot of the fumble.

Now when a professional football referee in perfect position and on a field marked with lines every yard can misjudge where a ball went out of bounds, and even misidentified what had hit the pylon, failed so completely in his perception how can CIT expect laypersons to accurately place an object in the sky roaring by unexpectedly at nearly 500 mph with no grid for reference?

This is why physical evidence trumps eyewitness accounts for such an event.

 

[Bobert]

Do I have this right?
TF has been debating MAC but then after not getting the answers that do not agree with his fantasy he turns around and basically trash talks MAC who he knows hadn't logged onto JREF for a month?
Do I have this right?
He then starts to demand that MAC post his real name.
When Mac responds to him TF then says that he (TF) isn't even a qualified engineer but he has "experts" who are willing to debate with MAC.
Wait a second wasn't the point of TF going over to MAC's forum to get what he felt was an "expert"?
This is confusing.
It seems that time is being wasted with TF when he isnt the one who wears the pants in the CIT family.

 

[Turbofan]

Do I have this right?
TF has been debating MAC but then after not getting the answers that do not agree with his fantasy he turns around and basically trash talks MAC who he knows hadn't logged onto JREF for a month?
Do I have this right?
He then starts to demand that MAC post his real name.
When Mac responds to him TF then says that he (TF) isn't even a qualified engineer but he has "experts" who are willing to debate with MAC.
Wait a second wasn't the point of TF going over to MAC's forum to get what he felt was an "expert"?
This is confusing.
It seems that time is being wasted with TF when he isnt the one who wears the pants in the CIT family.

Wait, do I have this right? Bobert has posted nonsense without reading the
previous replies?

Mac is not an FDR expert. Period. Admitted.

You guys cry all day and night that our 35+ year Accident Ivestigators, engineers,
pilots, etc. aren`t worth listening to, but you will buy into a theory of
someone with less expertise with the equipment?

Nice. Makes a lot of sense.

Does anyone here know what a Zener diode is/does? or a voltage regulator works? MIL SPEC?

 

[WildCat]

Mac is not an FDR expert. Period. Admitted.

Oddly enough, neither is anyone at PfffT. Hmmmmm...

 

[Jonnyclueless]

Does anyone here know what a Zener diode is/does? or a voltage regulator works? MIL SPEC?

I am sorry, is this question supposed to make people think you have any experience with FDRs? You don't. You know it. Drop the act.

 

[jaydeehess]

I'm not an electrical engineer. Those who will be signing up here to debate
will use their real name. I just might throw mine in for good measure.

My experts will not come here to debate a faceless account and anyone
with enough expertise to make claims about a system should very well
offer a name for reference purposes.

You are and have been shilling for the 'experts' at PfT.

However, the idea that no information posited by a person posting here can carry any weight unless that person uses his real name is ridiculous. Either a technical points stands or it doesn't, it does not matter whether or not a name is attached to it.

As mentioned before, I'm not the one who will be debating your points.
I don't know the systems as well as the engineers who disagree with
the statements made here that a transient could initiate an erase command
and wipe out previously recorded data.

Then they could post here with their reasoning for that belief. Better yet they could write up a consise technical paper outlining their belief that the FDR data set does not illustrate the same flight path as the downed poles and submit it to organizations which have access to the recognized expertise you, and PfT, claim they desire an opinion from. Instead you choose to concentrate on doing this on the internet with persons you believe do not have the expertise to render an opinion.

I've measuried transients on digital transmission lines (not avionics) and noticed
that the duration of the peaks (non filtered) is a few milliseconds at best.

Hmm, so have I and if by a few milliseconds you mean up to 200-300 milliseconds then I can agree and at whole powers of ten above the regulated voltage. I no longer have access to a storage scope. Too bad.

Correct me if I'm wrong, but your transient theory assumes that an erase function
was already in process, or starting in order to make sense?

IIRC you are wrong. IIRC he stated it had just taken place and data had started to be written to that erase block. 3-6 seconds worth for this particular senario, but this was only ONE possible senario.