"Disappering" planes!

[gumboot]

Originally Posted by Senenmut

is there anyway that a plane (plane A) could turn of its transponder and another (say a drone plane) put the code of plane A (or another code) into its transponder and basically turn into plane A or at least look like plane A on radar?

Yes, there is a way it could happen. Could it go unnoticed? Highly unlikely. Does the scenario make sense in regards to 9/11? Not in the least.

Originally Posted by Senenmut

pay attention to the map and the animation and the fact that:

Senenmut, I've already explained this, but you obviously didn't read it, so please pay VERY close attention to my following responses. They detail a vital piece of information that is missing from your analysis.

Originally Posted by Senenmut

Within the area that the hijackings took place, there are two areas with no primary radar coverage that stretch up towards Canada.

The map you're referring to shows radar coverage at 5,000ft above ground level. Coverage is greater at higher altitude, where the hijackings occurred. The only gaps in primary radar coverage in the entire continental USA are a few tiny isolated spots over the Rocky Mountains.

Originally Posted by Senenmut

Flight 11 switched off its transponder right next to an area with no primary radar coverage.

The map you're referring to shows radar coverage at 5,000ft above ground level. Coverage is greater at higher altitude, where the hijackings occurred. The only gaps in primary radar coverage in the entire continental USA are a few tiny isolated spots over the Rocky Mountains.

Originally Posted by Senenmut

Flight 77 switched off its transponder right next to an area with no primary radar coverage.

The map you're referring to shows radar coverage at 5,000ft above ground level. Coverage is greater at higher altitude, where the hijackings occurred. The only gaps in primary radar coverage in the entire continental USA are a few tiny isolated spots over the Rocky Mountains.

Originally Posted by Senenmut

Flight 93 switched off its transponder right next to an area with no primary radar coverage.

The map you're referring to shows radar coverage at 5,000ft above ground level. Coverage is greater at higher altitude, where the hijackings occurred. The only gaps in primary radar coverage in the entire continental USA are a few tiny isolated spots over the Rocky Mountains.

Originally Posted by Senenmut

United Flight 175 switched off its transponder next to United Flight 93.
We have two incidences where a hijacked plane came very close to a non-hijacked plane. (What are the odds?) Flight 11(hijacked) meets Flight 175 (not hijacked). Flight 175 (hijacked) meets Flight 93 (Not Hijacked).

This is utter drivel. Firstly, UA175's transponder was never turned off. Secondly, when UA175 was hijacked (and the transponder code was changed), UA93 was miles away, and just taking off (while UA175 was at or near cruising altitude).

Thirdly, the proximity of AA11 and UA175 should be of no surprise when you consider they took off from the exact same runway (4R at Logan International) only 15 minutes apart, and were both heading to the same place (LAX).

Fourthly, you focus on these supposed "meetings" and ignore much closer meetings - UA175 nearly collided with at least two other aircraft during its flight, reportedly coming within 200ft of DA2315.

[Senenmut]

Originally Posted by Obviousman

Yes. It's just a code. Even though, there is absolutely no evidence that it happened. Until someone can come up with evidence - not speculation, not conjecture but proof - then it is not worth considering when compared to factual data.

thanks for the input.

[Senenmut]

Originally Posted by gumboot

Hi Guys,

Just to clear up a pointless little argument, St Albans, VT (QHB) is a FPS-20 series PSR (Primary Surveillance Radar) with a Mode-S SSR (Secondary Surveillance Radar). The PSR became operational on 1 Jan, 1990, and the SSR became operational on 30 Jan, 1996.

I would eyeball the nearest ARSR-4 site from St Albans as North Truro, MA (QEA).

Data is from the FAA's NAS Architecture.

thanks for telling the skeptics i was right. anyway, can you describe that data from the faa's nas architecture. is that the software ptech designed for the faa?

[gumboot]

Originally Posted by Senenmut

thanks for telling the skeptics i was right.

You're right about the radar site, but you're utterly wrong about your claim of "gaps in primary coverage".

Originally Posted by Senenmut

anyway, can you describe that data from the faa's nas architecture. is that the software ptech designed for the faa?

Ptech is a company. If you want to check out their data, do it yourself, I have no time for Conspiracy Theorists any more.

[Senenmut]

Originally Posted by gumboot

You're right about the radar site, but you're utterly wrong about your claim of "gaps in primary coverage".




Ptech is a company. If you want to check out their data, do it yourself, I have no time for Conspiracy Theorists any more.

the map speaks for itself.

unfortunaetly it is not a conspiracy. ptech software was on faa computers along with many other computer systems that day.

http://ourworldinbalance.blogspot.co...ira-singh.html

question - What do you mean P-Tech was a ‘Middle Eastern’ company?

Indira Singh - Well, that’s what subsequently was revealed in the phone calls, that their financiers, their founder, their investors, were all Saudis. And I said, “So? What?” And they said, “One Saudi has been placed on the US terror list, October 12, 2001.” It got very quiet and I said, “You better have proof of that because having thrown that into my lap now, this is not something that I can ignore. I have to follow up on it.” This is not something I could ignore, or pretend would go away or have someone else handle. This is risk management, the highest levels of one of the largest banks in the world, it is my responsibility to deal with this. And I said, “How can I get proof of this?” And that’s when they started saying, you need to talk to Jeff Goins, one of 3 people in P-Tech who knew of this relationship. You see, it was that well hidden within P-Tech. And so I subsequently called Jeff Goins and I said, “If this is true… (P-Tech is a private company, so this information would only be privy to those on the inside.)… did you report it anywhere? That someone who has been placed on the US terror list is Key Funder, Angel Investor, to a company whose software is utilized at the highest levels of almost every government and military and defense organization in this country, including, the Secret Service, the FBI, the Department of Defense, the House of Representatives, the Treasury Dept., the IRS, the US Navy, the USAF, and, last but not least, the FAA.”

[Senenmut]

gumboot-
would you care to explain where you acquired this information. i cant find anything about a false second track being created. and if that false second track was created, what would the track look like?

"On 9/11, because aircraft were disappearing from radars, some centres started to use the TSD to track flights, however obviously this is problematic when flights are changing course. It was also used by centres to monitor aircraft outside their airspace. A false second track was created for AA11, which was the cause of the phantom AA11 report."

[9/11 Chewy Defense]

I'd like to know where these alleged "gaps" are in the radar system?

[gumboot]

Originally Posted by Senenmut

the map speaks for itself.

It does. The problem is you don't understand what it's actually showing.

Originally Posted by Senenmut

unfortunaetly it is not a conspiracy. ptech software was on faa computers along with many other computer systems that day.

Ptech's software is an organisation simulator that is used to test how changes to an organisation's structure will affect its operation - say what will happen if the cleaners department is closed and contracted to a private company, or what will happen if accounting and facility managment are combined into a single department.

While the Ptech thing is very interesting, and if used by terrorists would have given them insight into the structure of US government organisations, there's nothing the software does that could have had any impact on the events of 9/11 whatsoever.

[Cheap Shot]

Originally Posted by Senenmut

:lets let cheapshot answer the question.
is there anyway that a plane (plane A) could turn of its transponder and another (say a drone plane) put the code of plane A (or another code) into its transponder and basically turn into plane A or at least look like plane A on radar?

Not exactly the way you state it, it wasn't common practice for our USAF, but they used to depart E-135 aircraft from Alaska and they would position themselves under the belly and a little intrail from Air Carriers flying close to Kamchatka, north of Korea in Russian Airspace. Working in concert if the aircraft abvoe knew about the aircraft below they could simutaneously switch one transponder off and turn the other one on. and appear to look like the same aircraft.

Does it make any sense not really, the drone aircraft idea is really dumb, I would forget about it. Can it be done yeah with millions of dollars and a lot of people involved. Why do it in concert with another aircraft, just have the plane take off and fly into a building. If you had a remote location with a big enough runway, and where you had to conduct years of testing without anyone noticing. It would be cheaper and more effective to hire 4 to 5 hijackers, teach one how to fly and crash them into a buildiing.

[Cheap Shot]

From a controller perspective, you either have an ARSR 4 or an ATCRBS site, they are both long range radar as far as we are concerned and one has primary and the other one does not. yes St. Albans is a Mode S site. we have called it an ARSR for years, didn't really know it was designated as an FP20. We knew it had Mode S we just assumed it was an extra atenna.
Either way it still had primary radar which was the concern of the orignal post.

[Cheap Shot]

Originally Posted by parky76

id love if someone from the FAA could confirm or deny that they have a button that can easily isolate flights that have switched-off transponders.

and id love if someone from the FAA could confirm or deny if they have ever had practice and training sessions with the DOD of how they would assist in the tracking and interception of a hijacked airliner.

i seriously doubt they had.

Yes we do, at high altitude sectors if you lose the beacon target you press an "All Primary Button" and the primary target appears.

Prior to 9-11 yes we had an occasional exercise that were geared for the Military, not neccesarilly for the FAA. We did have a large sacle Hijack exercise in 1995 I beleive that involved the FAA, Airlines, DOD, and Canada.

But we did have some real world hijackings as well.

[Simplicissimus]

Hi everybody!

I ahve stumbled across information implying Ua175 disappeard from primary radar radar for a short timre. I am still puzzled.

1. "12:46:48: last beacon hit/ no primary (good primary elsewhere)", p. 20


911mythsdotcom/ images/0/0b/3_AWA_207_Fax_Draft_Transcript _W-9029p _Sector_R4 2_RED ACT.p df

2. 1 min 55 sec: Narrator says Ua175 "disappeared":

videodotzgoogle.fr/videoplay? docid=2707152614760625 109&q=Air+Traffic+Con #

3. Miles Kara in his August 24 note: "...it was lost as a primary target.."

/w w w .or edigger61.o rg /

[DavidJames]

Originally Posted by Simplicissimus

Hi everybody!

I ahve stumbled across information implying Ua175 disappeard from primary radar radar for a short timre. I am still puzzled.

1. "12:46:48: last beacon hit/ no primary (good primary elsewhere)", p. 20


911mythsdotcom/ images/0/0b/3_AWA_207_Fax_Draft_Transcript _W-9029p _Sector_R4 2_RED ACT.p df

2. 1 min 55 sec: Narrator says Ua175 "disappeared":

videodotzgoogle.fr/videoplay? docid=2707152614760625 109&q=Air+Traffic+Con #

3. Miles Kara in his August 24 note: "...it was lost as a primary target.."

/w w w .or edigger61.o rg /

So?

[Simplicissimus]

This contradicts the official story. Ua 175 never disappeared from primary like AA77. but just switched transponder code twice.

[Dave Rogers]

Originally Posted by Simplicissimus

This contradicts the official story. Ua 175 never disappeared from primary like AA77. but just switched transponder code twice.

This would only matter if there were such a thing as an 'official story'. There isn't; there's just what happened. If the evidence suggests that UA175 was lost from primary radar, and somebody else says it wasn't, then the evidence may be misleading or the somebody else may have made a mistake. In neither case does it cast significant doubt on the well-established fact that it was under the control of a group of hijackers who crashed it into WTC2.

Dave

[funk de fino]

Originally Posted by Simplicissimus

This contradicts the official story. Ua 175 never disappeared from primary like AA77. but just switched transponder code twice.

So?

[NutCracker]

Originally Posted by Simplicissimus

This contradicts the official story. Ua 175 never disappeared from primary like AA77. but just switched transponder code twice.

Please do elaborate on the implications.

[Simplicissimus]

As I said I am puzzled, thus I am asking everybody for an explanation, I do not have a specific theory at this moment.

[progge]

Originally Posted by Simplicissimus

Hi everybody!

I ahve stumbled across information implying Ua175 disappeard from primary radar radar for a short timre. I am still puzzled.

1. "12:46:48: last beacon hit/ no primary (good primary elsewhere)", p. 20


911mythsdotcom/ images/0/0b/3_AWA_207_Fax_Draft_Transcript _W-9029p _Sector_R4 2_RED ACT.p df

2. 1 min 55 sec: Narrator says Ua175 "disappeared":

videodotzgoogle.fr/videoplay? docid=2707152614760625 109&q=Air+Traffic+Con #

3. Miles Kara in his August 24 note: "...it was lost as a primary target.."

/w w w .or edigger61.o rg /

There is "no hard evidence" that UA 175 really dissapeared from primary radar. The early FAA reports are misleading sometimes, and you cited a very early notion (September 13th). AFAIK, the report you mentioned is the only one including any notion indicating a lack of primary coverage in the area UA 175 flew in. So the case is not as strong as it may seem to be.
As to 1 and 3, you can read the working hypothesis from Miles Kara in his blog in the "Transponders and Ghosts" section in the comments.

Quote:

Whatever the tactical plan, there is no question that al Shehhi changed the transponder code immediately after AA 11 struck. Now, that also happens to be about the time of the odd transcript entry you mention. So, two things. One, it is a reference to AA 11 or, more likely, it is a reference that they lost the secondary on UA 175 original transponder code and didn’t see a primary because there was none, the aircraft was now a Mode 3 intruder. It was never primary only to the FAA radar system.

Source

As to 2, the FAA controllers were puzzled about AA 11, and about the "intruder" then (which turned out to be UA 175). I´m not sure if they ever looked for primary targets with respect to UA 175. Another explanation for the "disappeared" comment might be that UA 175 simply dissapeared from secondary radar screen (first transponder code change wasn´t noticed by ATC).

[T.A.M.]

Originally Posted by Simplicissimus

This contradicts the official story. Ua 175 never disappeared from primary like AA77. but just switched transponder code twice.

1. Your Miles Kara quote seems to have been addressed at the very site you quoted,

Quote:

December 1, 2009

There seems to be some confusion abut my August 24 note concerning UA 175 lost as a primary target. The internal link is to an FAA document and, yes, UA 175 under its assigned transponder code was lost as a primary target; that “plane” ceased to exist except on TSD. What showed up on air traffic control scopes was a transponding intruder, an aircraft squawking an unassigned code. That intruder was, first, 3020, and then 3321.

http://www.oredigger61.org/

TAM

[carlitos]

Originally Posted by Simplicissimus

As I said I am puzzled, thus I am asking everybody for an explanation, I do not have a specific theory at this moment.

OK, but be aware that you are on thin ice "Just Asking Questions" around here. It usually ends only one way...

[T.A.M.]

The first point, the 12:46:48 entry,

1. We have no proof (though like he is) that the communication is about UA175. Other flights are mentioned in that log. No flight # is mentioned in that specific quote.
2. Even if it was lost from primary for AN INSTANT, this has ABSOLUTELY NO EFFECT on the official account of that day.

JHC talk about MINUTIA and A FINE TOOTH COMB.

give it up already.

TAM

[T.A.M.]

Your 2nd quote is 2nd hand interpretation by Tom Brokaw based on his information which may be from (A) Botaglias memory, (B) a transcript, or (C) actual tapes...who knows...talk about unreliable. So because BROKAW says that "Botaglia noticed" that UA175 "Had also disappeared" you take this as proof that they lost it as a primary target???

holy crap

TAM

[ElMondoHummus]

Folks, lost doesn't have to mean "dropped from radar screen". Stop and think about this for a moment:

FL175 changes its transponder, then alters it's direction. When an ATC goes looking on primary for it, he's not going to know it changed direction, so along what path would he be looking? The path it was originally supposed to fly along, not the route it eventually did take. That is exactly how FL77 got "lost"; it never actually disappeared from radar, and John Farmer's post-event evaluation of the radar tracks prove this. What happened is that it was "lost" in the sense that the controllers couldn't find it once it (I'm talking Flight 77 here) stopped broadcasting its proper transponder code. The real primary radar "blip" would be elsewhere on the screen, and in an unexpected location.

It's not a stretch to think the same thing might have happened to FL175.

Now, I'll have to defer to Cheap Shot on this, since he was actually in Boston Center at the time, but it seems to me that once FL175 changed transponders and turned, it would be easy to not figure out which dot on the display it was. That right there would be a perfectly logical reason for controllers saying a flight was "lost". Read the quotes: "last beacon hit" i.e. last spot the proper transponder code was read. "No primary": Could mean that they couldn't locate it on primary, and most likely because at first, they'd have no reason to look anywhere else other than along it's original flight path. Again, that's exactly the case with Flight 77. And "it was lost as a primary target": Lost as in dropped from the screen at all? That's not correct, as Farmer's reconstruction shows. Rather, lost as in the controller in the moment, deprived of information, didn't know where it was on his screen, and had no reason to think that an unlabeled splotch well away from the filed flight path would be the same jet.

You don't have to read those controller quotes and report quotes as saying "Flight 175 disappeared from radar". It is perfectly logical to read them as "we can't find them". And there's a difference between the two.

Cheap Shot: Feel free to correct or expand on anything I've written here. You know way more about this than I do, by orders of magnitude.

[progge]

Originally Posted by ElMondoHummus

Folks, lost doesn't have to mean "dropped from radar screen". Stop and think about this for a moment:

FL175 changes its transponder, then alters it's direction. When an ATC goes looking on primary for it, he's not going to know it changed direction, so along what path would he be looking? The path it was originally supposed to fly along, not the route it eventually did take. That is exactly how FL77 got "lost";

I do not think that this is the correct explanation. UA 175 did not change altitude before 8:51 and direction before 8:52, the notion "no primary" is from 8:47.

Originally Posted by ElMondoHummus

You don't have to read those controller quotes and report quotes as saying "Flight 175 disappeared from radar". It is perfectly logical to read them as "we can't find them". And there's a difference between the two.

Agreed, though

[TruthersLie]

Originally Posted by Simplicissimus

As I said I am puzzled, thus I am asking everybody for an explanation, I do not have a specific theory at this moment.

Most definately a lie.

Hello new twoof. Welcome to Jref.

now try to provide some proof ... maybe you will be the first one ever.

Unless of course you are just some dirty laundry... then you will eventually be banned.

[ElMondoHummus]

Originally Posted by progge

I do not think that this is the correct explanation. UA 175 did not change altitude before 8:51 and direction before 8:52, the notion "no primary" is from 8:47.

Aieee... I think I'll have to go back to Gumboot's information and relearn the FL175 timeline. If the "no primary" came before it changed direction... well... Anyway, I'll do that when I get a chance.

ETA: Well, waitaminute... I'm not sure the time for the report where the "no primary" quote comes from is synchronized to the same time that the FL175 timeline is. Now I'd hope that whatever clocks the government investigators, plus the ATCs and other entities involved with the event would agree to better than 5 minutes difference, but my point is that it's entirely possible that they don't. Hell, I can find 3 or 4 clocks where I work that differ by around that amount. Anyway, my point is that time synchronization could possibly account for that difference. That's only a possibility, not a proven explanation, but it's not out of the realm of possibility.

[Cheap Shot]

Originally Posted by ElMondoHummus

Folks, lost doesn't have to mean "dropped from radar screen". Stop and think about this for a moment:

FL175 changes its transponder, then alters it's direction. When an ATC goes looking on primary for it, he's not going to know it changed direction, so along what path would he be looking? The path it was originally supposed to fly along, not the route it eventually did take. That is exactly how FL77 got "lost"; it never actually disappeared from radar, and John Farmer's post-event evaluation of the radar tracks prove this. What happened is that it was "lost" in the sense that the controllers couldn't find it once it (I'm talking Flight 77 here) stopped broadcasting its proper transponder code. The real primary radar "blip" would be elsewhere on the screen, and in an unexpected location.

It's not a stretch to think the same thing might have happened to FL175.

Now, I'll have to defer to Cheap Shot on this, since he was actually in Boston Center at the time, but it seems to me that once FL175 changed transponders and turned, it would be easy to not figure out which dot on the display it was. That right there would be a perfectly logical reason for controllers saying a flight was "lost". Read the quotes: "last beacon hit" i.e. last spot the proper transponder code was read. "No primary": Could mean that they couldn't locate it on primary, and most likely because at first, they'd have no reason to look anywhere else other than along it's original flight path. Again, that's exactly the case with Flight 77. And "it was lost as a primary target": Lost as in dropped from the screen at all? That's not correct, as Farmer's reconstruction shows. Rather, lost as in the controller in the moment, deprived of information, didn't know where it was on his screen, and had no reason to think that an unlabeled splotch well away from the filed flight path would be the same jet.

You don't have to read those controller quotes and report quotes as saying "Flight 175 disappeared from radar". It is perfectly logical to read them as "we can't find them". And there's a difference between the two.

Cheap Shot: Feel free to correct or expand on anything I've written here. You know way more about this than I do, by orders of magnitude.

A couple of things first if the aircraft was still at altitude the primary button is off. A controller based on how busy they were might not push the "All Primary Button" right away. THe data block remains when a transponder is turned off, the only thing that changes is the target and target indicator. The slash would disappear, and the diamond symbol would go to a triangle symbol looking for the beacon.

Don't know when they pushed the primary button, if the aircraft was in airspace below FL180 the controller would have his primary button already on.

Normally aircraft are not making drastic turns, so when you lose the transponder and you switch on the primary you'll find it very close by. The other issue is how much history is displayed. Ground clutter usually has no history, primary radar returns are easily identifiable by there history. history is preset by the controller if the controller has no history set it would take several sweeps to identify the primary target. If someone has say five history sweeps saved you would find the primary rather quickly even if it had made some turn, even mor so the history turns are very noticeable.

Every radar whether primary or secindary misses hits every now then, sometimes it is between sort boxes, sometimes not. however radar would never miss a minute an a half of hits. My guess it may have been a combination that the primary button wasn't selected right a way, and then they had to find it when they finally did. I am sure the actual raw data would indicate it was in radar the entire time.

[gumboot]

Originally Posted by ElMondoHummus

FL175 changes its transponder, then alters it's direction. When an ATC goes looking on primary for it, he's not going to know it changed direction, so along what path would he be looking? The path it was originally supposed to fly along, not the route it eventually did take. That is exactly how FL77 got "lost"; it never actually disappeared from radar, and John Farmer's post-event evaluation of the radar tracks prove this. What happened is that it was "lost" in the sense that the controllers couldn't find it once it (I'm talking Flight 77 here) stopped broadcasting its proper transponder code. The real primary radar "blip" would be elsewhere on the screen, and in an unexpected location.

This is incorrect. AA77 was "lost" on radar, in the sense that there was no primary display for the aircraft (for approximately 9 minutes, after which it reappeared on primary but obviously in a very different location to where expected). The data that Farmer used to prove there was primary coverage for the entire flight was "dumped" data - that is primary data that the Radar Data Processor received, but never displayed.

It's a crucial point to understanding the radar side of 9/11 that not all radar data is displayed on a radar scope, the vast majority (as much as 90%) is "dumped". Additionally of importance, all of the "dumped" data is recorded, and can be accessed for post-event analysis.

Originally Posted by ElMondoHummus

It's not a stretch to think the same thing might have happened to FL175.

UA175 was a very different scenario to the other flights. As mentioned before, the transponder code was changed, but never turned off. We know this for a fact because FAA controllers were able to watch the flight as it rapidly descended into Manhattan - something they could not have done without transponder returns giving altitude. UA175 was eventually lost on radar - when it flew below radar coverage (at ~7,000ft AGL from memory). At that point local radar sites tried to pick it up (because the short-range ASR radars used by TRACON and ATCT sites have lower altitude coverage than the long-range ARSRs) and a visual identification was made by (I think) Newark Tower moments before impact.

[ElMondoHummus]

Originally Posted by gumboot

This is incorrect. AA77 was "lost" on radar, in the sense that there was no primary display for the aircraft (for approximately 9 minutes, after which it reappeared on primary but obviously in a very different location to where expected). The data that Farmer used to prove there was primary coverage for the entire flight was "dumped" data - that is primary data that the Radar Data Processor received, but never displayed.

It's a crucial point to understanding the radar side of 9/11 that not all radar data is displayed on a radar scope, the vast majority (as much as 90%) is "dumped". Additionally of importance, all of the "dumped" data is recorded, and can be accessed for post-event analysis.

Ouch... my writing skills bites me again. Yes, I did know this; Cheap Shot explained to me that FL77 was unviewable to Indianapolis due to their inability to view that "sort box" (is that the right term, Cheap Shot?). I didn't mean to imply that it was on the primary display the entire time for Indianapolis Center; Cheap Shot told me that it couldn't have been. But, I didn't word the post correctly in order to communicate that, and that's my failing.

On top of that, I should've been more clear when I wrote:

Quote:

What happened is that it was "lost" in the sense that the controllers couldn't find it once it (I'm talking Flight 77 here) stopped broadcasting its proper transponder code. The real primary radar "blip" would be elsewhere on the screen, and in an unexpected location.

Indianapolis Center could not locate FL77 once it stopped broadcasting its proper transponder code. But even if they had started looking on primary, it would not have shown up on their screens, as I recall. Cheap Shot can elaborate on who might have been able to see it, but Indianapolis Center could not have.

Now, the "real primary radar ''blip''" being elsewhere on the screen, and in an unexpected location is true, but I should have clarified that I was now discussing both other centers who could have read primary radar returns where FL77 was, and whichever center would have been tracking FL175. I didn't write things clearly enough to make this distinction, and that too is my fault. Thanks for the clarification, Gumboot. I wouldn't have realized I was being unclear without it.

Originally Posted by gumboot

UA175 was a very different scenario to the other flights. As mentioned before, the transponder code was changed, but never turned off. We know this for a fact because FAA controllers were able to watch the flight as it rapidly descended into Manhattan - something they could not have done without transponder returns giving altitude. UA175 was eventually lost on radar - when it flew below radar coverage (at ~7,000ft AGL from memory). At that point local radar sites tried to pick it up (because the short-range ASR radars used by TRACON and ATCT sites have lower altitude coverage than the long-range ARSRs) and a visual identification was made by (I think) Newark Tower moments before impact.

Yes, of course that's right. You know more about this than I do, far more. But remember: I was discussing Simplicissimus's quotes from the video and from Miles Kara "lost as a primary target". Without going to Kara's blog first and copying his explanation, I was merely trying to make a point that being "lost as a primary target" doesn't necessarily mean dropping from radar altogether, and most definitely not right at the hijacking at 8:47. All I was trying to say was that being "lost as a primary target" could be nothing more than no longer transmitting its proper transponder code and therefore being difficult to locate on primary. And that's all I was trying to say. That's why I also invited Cheap Shot to comment, and learned something from his discussion of sweeps and history; it might not have been as hard as I thought it was. Regardless, both Simplicissimus and I mistook those quotes as meaning "not found by the controller". But on reading Miles Kara's blog, I see that this was not the case.

And now that we're at this point - Simplicissimus: You shoud read Miles Kara's latest blog entry yourself. He explains what he meant in the quote you cited:

Quote:

December 1, 2009
August 24 note clarification. There seems to be some confusion abut my August 24 note concerning UA 175 lost as a primary target. The internal link is to an FAA document and, yes, UA 175 under its assigned transponder code was lost as a primary target; that “plane” ceased to exist except on TSD. What showed up on air traffic control scopes was a transponding intruder, an aircraft squawking an unassigned code. That intruder was, first, 3020, and then 3321.

So yes, he did indeed say it was 'lost as a primary target". But it did not fall out of radar coverage, not at that point. It only did so when Gumboot noted above, and that's when it dropped below 7,000 feet above ground level. And according to the NTSB flight path study for that flight, that was mere single digit minutes before it hit the tower. So the ultimate point is that no, the flight was not lost from radar. It was there, the controllers knew it was there, what was lost was the transponder info identifying it as FL175. The controllers never lost track of the jet itself on radar.

[Simplicissimus]

"He explains what he meant in the quote you cited"

This is just his interpretation.

[Mr.D]

Originally Posted by Simplicissimus

This is just his interpretation.

How dare he interpret his own quote! What a shill.

[progge]

To continue gumboot´s line of reasoning: This article from FAA controller Tom Lusch is an illuminating piece concerning the dissapearance of AA 77. The thesis is that the reason for the AA 77 radar hole should not be described as poor primary radar coverage for the sort box AA 77 was lost in, but as poor use of radar stations with excellent primary radar coverage for the accordant sort box. Subtle difference, eh?
Pretty straight demonstration IMO.

[gumboot]

Originally Posted by ElMondoHummus

Ouch... my writing skills bites me again. Yes, I did know this; Cheap Shot explained to me that FL77 was unviewable to Indianapolis due to their inability to view that "sort box" (is that the right term, Cheap Shot?).

That's sort of right. A "sort box" is the way the RDP divides airspace up into little boxes. They could see the sort box AA77 was in, but they couldn't see any primary radar in that particular sort box because of how the radar sites were assigned to it.

Originally Posted by ElMondoHummus

Indianapolis Center could not locate FL77 once it stopped broadcasting its proper transponder code. But even if they had started looking on primary, it would not have shown up on their screens, as I recall. Cheap Shot can elaborate on who might have been able to see it, but Indianapolis Center could not have.

I don't think anyone could have seen it. There may be some sort box overlap on the edges of the ARTCC zones, but AA77 was fairly central in Indy Center's airspace. They're the only ones who would be handling that particular sort box.

The guts of it is you have 9 LRRs feeding Indianapolis ARTCC.

Of those, three are beacon-only - that is there's no primary radar.

Any sort box, therefore, assigned to one of those three radar sites would not display primary coverage. One of them - Harmony, West Virginia (QHY) was assigned to the sort box where AA77 was hijacked. Harmony happens to only feed into Indianapolis Center.

While the odds of AA77 disappearing seem slim, you have to consider that actually being hijacked in Indianapolis Center, there was a 33% chance of it being hijacked in a beacon-only sort box.

For comparison Boston ARTCC (AA11 hijacking) has 11 feeds, only one of which is Beacon Only, and New York ARTCC (UA175 hijacking) has 10 feeds, all of which have primary. Cleveland ARTCC (UA93 hijacking) has 10 feeds, also all with primary.

[Dave Rogers]

Originally Posted by Simplicissimus

"He explains what he meant in the quote you cited"

This is just his interpretation.

Simplicissimus, there is a button marked "Quote" in the bottom right of the post window. If you press this button, it will take you to a posting window in which the post you're replying to is already quoted, together with a hyperlink to the original post. This makes it much easier for those reading your post to see what you're replying to, and to view the original post to see the quoted part in context. It would help in this case, as I can't easily tell what statement you're replying to.

In any case, it seems to me that the interpretation of a remark presented by the person who made it has a much better chance of being the same interpretation as he placed upon it when he made the remark. It would, therefore, be not "just" his interpretation, but his intended, and hence the correct, interpretation.

Dave

[funk de fino]

Originally Posted by Simplicissimus

"He explains what he meant in the quote you cited"

This is just his interpretation.

Thats a keeper!

[Simplicissimus]

The document he refers to has not been written by him, thus it is open to various interpretations. If Kara syas it is meant THIS way, it is just his interpretation.

[Dave Rogers]

Originally Posted by Simplicissimus

The document he refers to has not been written by him, thus it is open to various interpretations. If Kara syas it is meant THIS way, it is just his interpretation.

But you weren't questioning the document he referred to, you were questioning his own statement that UA175 was "lost as a primary target". Since it's his own statement, then his own interpretation of his statement is definitive. If you claim his statement means something other than he claims it means, then you're misrepresenting his statement, plain and simple.

Dave

[funk de fino]

Originally Posted by Simplicissimus

The document he refers to has not been written by him, thus it is open to various interpretations. If Kara syas it is meant THIS way, it is just his interpretation.

A double keeper, quit while you are ahead.