Flight 77 FDR research

Regarding IRS accuracy, the maximum rated speed is in TAS. As the cruising speed of the 757 can be as high as 600 kts TAS, 450 kts IAS at 500 ft is going to put it well inside its operational envelope.

If the IRS is not updated, it is expected to drift no more than 3nm in 8 hours.

The bigger questions are: how rapidly does the INS update its OWN position, and separately, how often is this recorded on the FDR?

[edit on 9-3-2007 by mirageofdeceit]

Originally posted by johndoex
Dont blame us that it fits any type of 'conspiracy'. Blame the NTSB. Perhaps you should try to do what we are doing in trying to get the NTSB/FBI to either correct their data (they cant as noted above), or explain it.

It's true, the NTSB animation holds the key. Obviously this will have to be addressed sooner or later. I've been mulling it over.

And no, we dont claim that 273 AGL was recorded at that time. Matter of fact, 273 AGL shows being recorded at 09:37:47, 2 seconds after supposed impact.

We combine the 273AGL at 2 seconds PRIOR to impact to show that the govt loyalist argument of '2 seconds' missing also does not fit into the govt theory...

Got it. sorry, no more tech. questions unless i know what I don't know and have checked for prev. expl. first.

And don't forget, Dark Blue, no matter what the data says as you read it, the north path is verified by the witnesses. Who saw it fly in from about 100-35 feet above ground. this clearly verifies the northern path and multiple-hundreds-foot flyover. So unless i'm misunderstanding Rob, your arguments don't hold up like theirs. Reality only actually happens one way. Don't get your fingers stained picking all those cherries!



[edit on 9-3-2007 by Caustic Logic]

Where can I get the lat/lon for the aircraft? I'm either totally blind or it's not in my data.

[edit on 10-3-2007 by mirageofdeceit]

It's in the L3 data I hear, the other main doc besides the CSV from the pilots.
z9.invisionfree.com... & (AAL 77 params.txt) I haven't checked, not sure I'd know it if I saw it.
If this is wrong, a quick search of previous pages should help clarify where it's from.
Good lucks my friend.

Thanks!

I was wondering: have people stopped working on this?

I have for the time being. looking at Pgon eyewitnesses now, tackling the PeantCon not PBB and the FDR.
www.abovetopsecret.com...
I'm COINTELPRO maybe! I learned this from Jack Tripper.
I'll come back to the FDR when I feel up to trying to unserstand the stuff that's been figured out here, still can't wrap my brain around it... I think those lat-long readings are key, as well as authenticity/correlation of the various sources used by P49T. At least for what I was trying to figure out. Everything else here, for me, is supporting evidence. Despite the technical discoveries, the main thing I eep seeing is these sources don't add up.

OK! I'll keep looking and post what I find.

Originally posted by mirageofdeceit
Thanks!

I was wondering: have people stopped working on this?

Haven't given up, just occupied elsewhere. I will be back later this week.
Re: DFDR: there is too much uncertainty in the data....

Some parameters have been manipulated by NTSB/FBI etc. according CTer's (mag heading)

Some parameters are useless due to inaccuracies of measurment and recording (lat/long) according top CTer's.

But they will hang their hat on the DME which has an accuracy only to the nearest 500 feet in an area of the flight profile that spans roughly 1,500 feet. (Citgo to Pentagon) Since the INS lat/long data is being dismissed, the CTer's can rely only on the DME data to plot the final position of the aircraft based on DFDR data. And the position, based on DME can only approximated within a 1,000 ft corridor based on the accuracy of the DME data (nearest 1/10th of a NM).

I'll illustrate later when I have more time.

Hi,

There are 3 IRS units on the aircraft. When taking IRS data, you have to average the position (known as triple mixing). See my point above about the allowable drift rate and speed ratings. The IRS units are within operational design spec for the duration of the flight.

For relevant, background research, check out the CIVA INS used on Concorde. She was a Mach 2.00 bird that was allowed to operate with a sub-sonic INS as #3. Above 606kts TAS, the #3 unit would not (could not) supply wind data, and displayed the wind as 0 degrees at 0 kts. Other than this, its accuracy was still very good over the 3 hours and 45 minutes that it would not have a positional update, over a distance of 3,200 nm.

The CIVA INS had an allowable, maximum uncorrected drift rate of 3 degrees in 15 hours, becoming unreliable for navigation after this time. Note that modern IRS units are derived from the same principles as this unit.

We are talking about 45 minutes and 200nm?? I'd take the IRS as accurate (the chances of a triple IRS failure or extreme inaccuracy of this magnitude occurring to all 3 IRS units over this time is extremely slim).

If I could find this data, I'd plot it and show you.

[edit on 12-3-2007 by mirageofdeceit]

[edit on 3/12/2007 by darkbluesky]

if you go here z9.invisionfree.com...
and watch the the two flight paths , the path that believers of the conspiracy say was the real path the plane took , the right wing is clearly
over the light poles that they say couldn't have been knocked down .

If you check my calcs on the altitude on Page 3 of this thread, and compare with the decoded FDR data found here: z9.invisionfree.com...

Accounting for the fact I have mis-calculated the altitude of the Pentagon lawn in my calcs, and making the differences up, I come to the same conclusion@ that it was 275 feet above the lawn of the Pentagon.

If it was descending at 5,500 ft/min, then in 1 second, the aircraft descended 5500 / 60 = 91 ft. In two seconds, it descended 91 x 2 ft = 182 ft.

275 - 182 = 93 ft AGL. It STILL didn't hit the Pentagon, even allowing for a two second gap in the data between the last reading and "impact".

The aircraft passed over the Pentagon with 93 - 70 = 23 ft to spare. Allowing for altimeter altitude (13 ft according to the Boeing tech drawings with the gear up to allow for the bottom of the engine nacelles) we get 23 - 13 = 10 ft clearance.

This still puts the aircraft 80 ft above the lawn, two seconds after the last data was recorded in the FDR.

Considering the aircraft clearly enters the official camera view LEVEL with the ground at about 15 ft, it is not possible that the aircraft suddenly dived in the last 150 ft and leveled out before hitting the Pentagon, at 450 kts. It would have gone nose first into the lawn (and we know that didn't happen).

We know it didn't bounce - the lawn is intact. Another point here: if it did bounce, it would leave the engines behind as these would impact first. Most people assume that when it "bounced" it bounced off the fuselage, but the engines are under-slung, and these would impact first, most likely ripping the wings off in the process, and creating a fireball SHORT of the Pentagon (think of the Boeing 720 fuel test aircraft from the 80s). We'd have scorched earth, a crater where it dug in, and a general mess. But the lawn is actually intact.

If it didn't dive, and therefore didn't/couldn't hit the bottom of the building as is claimed (with a level attitude), the only place it went was over. There is no-where else it could have gone given the damage to the Pentagon, the lack of damage to the lawn, and the aircraft altitude, speed, and rate of descent.

[edit on 13-3-2007 by mirageofdeceit]

I'm not an expert in explosions, but if oyu look closely at this: en.wikipedia.org...:Pentagon_video_security4.jpg

I would have expected the fireball to come out of the bulding, the way the aircraft went into it. This clearly looks like it blew the top of the building out???????

Refer to the aircraft impacts with the WTC for an idea of what I would have expected the fireball to behave like.

[edit on 13-3-2007 by mirageofdeceit]

Originally posted by mirageofdeceit


If it was descending at 5,500 ft/min, then in 1 second, the aircraft descended 5500 / 60 = 91 ft. In two seconds, it descended 91 x 2 ft = 182 ft.

Perhaps its rate of descent was >5500 fpm during the last two seconds of its flight.

Assuming it was, it would not be flying level with the ground as we see in the official videos.

So, why is it level in the official videos? That is the next part of the puzzle.

Sorry guys I don't have more to offer, but as for level: the vid is from so great a distance, and with fisheye, I'm not sure how high it really was, if the video is correct. Could be 25 feet or more, and only captured in one frame, at one frame/sec means this is less than one seond from impact. Does that fit? X-foot alt to imapct height of about five feet in something like 0.75 sec? Just a thought...

You might be interested in this thread over here:

P4911T Link

Note the quote by johndoeX:

Conversation with our FDR Expert (although pilots already know this):

FDR Expert: Oh if you have DME and VOR you use that every time. DME is very accurate, the trouble with lat/long is it relies on GPS data which is all under the control of the military, if they wanted to they can pretty much make that plane appear anywhere they want from the lat/long. So yea every time use the DME.

IRS isn't updated by GPS, for the reason I stated in the thread over there:

The IRS would be updated using DME updates, to maintain system accuracy. the GPS would NOT be used for this function, for the fact that the GPS system could indeed be made inaccurate. To update the IRS from the GPS would render the IRS useless as a backup in the event of GPS failure or positional error, as it would have the same positional errors the GPS system had before it was deemed unreliable for navigation. This is an unacceptable scenario in commercial aviation and is not permitted.

What are peoples thoughts on this? Their FDR guy spreading dis-info? IRS isn't updated by GPS, so the IRS accuracy can't be affected remotely (as is being suggested). Their plots on Google Maps don't make much sense (especially at the beginning of the flight) as the aircraft is a significantly long way from its real location, having been aligned (it is re-aligned before every flight). Considering we are talking about a flight that lasted around 45 minutes, with plenty of DME stations around from which to conduct updates, the IRS system should be more accurate that it was.

I'll find the requirements for GPS nav (I think the FAA site has them) on required navigation hardware in order to use GPS as primary nav.

Note that GPS is not fitted to all aircraft with IRS as it isn't a requirement for IRS functionality, but GPS is deemed more accurate, so it can be used where available, but only if the requirements for backup are met.

From memory:

To use GPS as primary nav requires IRS ** and (IIRC) ** VOR/DME backup.

To use IRS as primary nav requires VOR/DME backup, unless flight is across an ocean where there are no VOR/DME stations for thousands of miles, then IRS system accuracy and number of serviceable units are checked prior to entering oceanic airspace. If the criterion are not met, then the flight has to be aborted.

[edit on 14-3-2007 by mirageofdeceit]

Mirage, What does the IRS acronym stand for? I've been assuming you meant INS (inertial navigation system). Is IRS something different?
Thanks

IRS = Inertial Reference System. It is the same principle as INS, but you can't use the unit directly for navigation as there is no way to provide it way point co-ordinates.

On an INS you enter your way points (flight plan) into it and fly using the INS the way modern FMCs are used.

With IRS, it simply provides inertial position data to other systems that use it to navigate (so the FMC is the nav system, but gets its position from the IRS).

Mirage - What is your opinion regarding the fact that the DME data shows steady at 3.2 NM from time 37:23 to 37:39? Is it an issue of update frequency?