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Flight93 and "missing 3 minutes"

mcMike

Student
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Joined
Sep 21, 2006
Messages
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Could someone explain the "missing 3 minutes", the time difference in raported UA93 crashtimes?

1) NTSB raports that UA93 crashed 10:03:10 (EDT)
The FDR ends to 10:03 and so does the CVS. Also NTSB states in the Flight Path Study; UA-93 Radar Ground Track (page 3) the impact time 10:03:11. So we have FDR, CVS and Radar Ground Track backing the 10:03 time for NTSB.
http://www.ntsb.gov/info/UAL93FDR.pdf (UA93 FDR-report)
http://www.ntsb.gov/info/Flight _Path_Study_UA93.pdf (UA93 Flight Path Study)

2) Cleveland ATC reports crashtime 10:06 (EDT)
"They said to disregard. The aircraft had turned to the south and they lost radar contact with him."
It was 10:06 a.m.
http://www.post-gazette.com/headlines/20011028flt93mainstoryp7.asp
Don't know how reliable this is though?

3) Seismologic stations raports that UA93 crashed 10:06:05+-5 (EDT)
Lamont-Doherty Earth Observatory of Columbia University, Palisides N.Y
Won-Young Kim and Gerald R. Baum
"We positively identified seismic signals associated with United Airlines Flight 93 that crashed near Shanksville, Somerset County, Pennsylvania. The time of the plane crash was 10:06:05+-5 (EDT)"
http://www.mgs.md.gov/esic/publications/download/911pentagon.pdf

4) The Aircraft-To-Ground Communication- transcript
between Cleveland ATC/UA93 and UA93 CVS-transcript seems to point that the "clocks" were in sync between the UA93 and Cleveland.
http://www.ntsb.gov/info/ATC _Report_UA93.pdf (Comm. transcript)
http://download.npr.org/anon.npr-www/documents/2006/apr/moussaoui/cockpit_transcript.pdf (CVS-transcript)

What could be the reason for 3 minute misaligment?
Thanks.
 
i would assume it was just some sort of error... is there a theory as to why there would be some sort of conspiracy involved in this missing three minutes? or is it just "suspicious"?
 
What's so suspicious about clocks not being synchonized?

Ask five people for the time and see what happens.

You do know that there are time discrepancies between GPS and UTC.
 
Laith is banned at 1:00 AM...McMike makes his first post at 6:00 AM.

Too bad they missed each other. They might have had a lot to talk about.
 
uruk said:
What's so suspicious about clocks not being synchonized?
Click to expand...

3 minutes? Sorry but It's not that. As I stated The Aircraft-To-Ground Communication- transcript points out that the Cleveland ATC and UA93 clocks were in sync. (1 sec accuracy in ATC recording times and CVS).

uruk said:
You do know that there are time discrepancies between GPS and UTC.
Click to expand...

Actually I don't and would be happy to know.
 
Spektator said:
Laith is banned at 1:00 AM...McMike makes his first post at 6:00 AM.

Too bad they missed each other. They might have had a lot to talk about.
Click to expand...

Who is Laith and what he has to do with this issue? Does he hold the anwser?

Never mind. I don't quite understand what is your point but I see what you try to imply. Was my question not legimite or was it just beyond your knowledge? Still, you decided to post meaningless reply without even slighty addressing the subject. Nice work and nice attitude. Keep up such good sceptic thinking !!!

Let me test your sceptisim. Don't you find the subject questionable?
FDR, CVS, Ground Track Radar provides impact time 10:03
Seismic stations, ATC radar provides impact time 10:06
Clocks are proved to be in sync.

Still, you don't find anything here to be looked for? And you call yourself a sceptic? Well, sir. I like to think myself as a sceptic too. But in contrary to you (apparently) I like to find out the explanations to questions. And whatever you believe of me I am not a CT. Maybe you care to look my other posts (even thought there aren't many).

And finally just FYI. I found the explanation elsewhere already myself.
 
Hi Mike,

This is mentioned in the 911 commissions report.

168. Ibid., pp. 23­27. We also reviewed a report regarding seismic observations on September 11, 2001, whoseauthors conclude that the impact time of United 93 was "10:06:05±5 (EDT)."Won-Young Kim and G. R. Baum,"Seismic Observations during September 11, 2001,terrorist Attack," spring 2002 (report to the Maryland Depart-ment of Natural Resources). But the seismic data on which they based this estimate are far too weak in signal-to-noise ratio and far too speculative in terms of signal source to be used as a means of contradicting the impact time established by the very accurate combination of FDR, CVR, ATC, radar, and impact site data sets.These data sets constrain United 93's impact time to within 1 second, are airplane- and crash-site specific, and are based on time codes automatically recorded in the ATC audiotapes for the FAA centers and correlated with each data set in a process internationally accepted within the aviation accident investigation community. Further more, one of the study's principal authors now concedes that "seismic data is not definitive for the impact of UA 93." Email fromWon-Young Kim to the Commission,"Re: UA Flight 93," July 7, 2004; see also Won-Young Kim,"Seismic Obser-vations for UA Flight 93 Crash near Shanksville, Pennsylvania during September 11, 2001," July 5, 2004.

http://www.insightful.com/infact/911/corpus/report_472_462.html

I hope this helps.
 
stateofgrace said:
Hi Mike,

This is mentioned in the 911 commissions report.

I hope this helps.
Click to expand...

Yes. Thank you.

That was the first piece of information I found myself. I accept it as plausible explanation but still wonder why Mr. Won-Young first stated:
"Although, seismic signals across the network are not as strong and clear as the WTC case (see Kim et al., 2001), three component records at station SSPA (= 107.6 km) shown in Figure 6 are quite clear. The three-component records at SSPA are dominated by strong Lg arrivals, whereas the Pg waves are difficult to discern and have amplitudes comparable to the noise level. This is typical for seismic waves generated by airplane impacts and crashes. The seismic signals marked as Sg in Figure 5 propagated from the Shanksville crash site to the stations with approximately 3.5 km/s. Hence, we infer that the Flight 93 crashed around 14:06:055 (UTC) (10:06:05 EDT)."

The whole seismic-raport here:
http://www.mgs.md.gov/esic/publications/download/911pentagon.pdf


The Cleveland ATC "lost from radar 10:06" seems to be just a myth which is based on some misinterreption and keeps living. There are no reliable sources to back it up. But it is used in many news-articles.
 
mcMike said:
Yes. Thank you.

That was the first piece of information I found myself. I accept it as plausible explanation but still wonder why Mr. Won-Young first stated:
"Although, seismic signals across the network are not as strong and clear as the WTC case (see Kim et al., 2001), three component records at station SSPA (= 107.6 km) shown in Figure 6 are quite clear. The three-component records at SSPA are dominated by strong Lg arrivals, whereas the Pg waves are difficult to discern and have amplitudes comparable to the noise level. This is typical for seismic waves generated by airplane impacts and crashes. The seismic signals marked as Sg in Figure 5 propagated from the Shanksville crash site to the stations with approximately 3.5 km/s. Hence, we infer that the Flight 93 crashed around 14:06:055 (UTC) (10:06:05 EDT)."

The whole seismic-raport here:
http://www.mgs.md.gov/esic/publications/download/911pentagon.pdf


The Cleveland ATC "lost from radar 10:06" seems to be just a myth which is based on some misinterreption and keeps living. There are no reliable sources to back it up. But it is used in many news-articles.
Click to expand...

Could it be something as simple as 10:06 is when Cleveland ATC official logged that it was no longer on radar; as opposed to when someone said, "I don't see it on the screen anymore."?
 
Arkan_Wolfshade said:
Could it be something as simple as 10:06 is when Cleveland ATC official logged that it was no longer on radar; as opposed to when someone said, "I don't see it on the screen anymore."?
Click to expand...
i figured it was an estimate, IIRC radar does not cover all the way to the ground, so they might have estimated a crash time based on the decent speed when it was no longer on radar, of course if the plane increased its decent rate after going under radar their estimate would be off

or as you say it could also be the time they decided "its not coming back" and logged it
 
Before we waste time trying to explain something which seems trivial to me, what do you think the importance of these "missing" minutes is?
 
mcMike said:
3 minutes? Sorry but It's not that. As I stated The Aircraft-To-Ground Communication- transcript points out that the Cleveland ATC and UA93 clocks were in sync. (1 sec accuracy in ATC recording times and CVS).
Click to expand...
notice what the ntsb report also says on page 3:
http://www.ntsb.gov/info/UAL93FDR.pdf
"if the data stream is interupted, sync words will not appear at the proper interval or sequence. and time reference will lost untill the subframe pattern can be established."
The report then goes on to say that 2 additional subframes which are equivalent to one second each was not validated plus an additional subframe which was determined to be a repeat of the previous frame. That's three seconds of uncertainty in the UA93 data log.

Now concerning the Lamont-Doherty siezmic info: (this is a repost of mine from another thread concering LDEO siezmic data)

I was doing some looking around and found out that time discrepancies can and do happen in siezmic data.
According to this site the LDEO uses the CNG-5TD strong motion accelerometers.
http://www.ldeo.columbia.edu/LCSN/intro.html

According to thier data sheet:

http://www.ldeo.columbia.edu/LCSN/News/CMG-5TD_rev2.pdf#search="CMG-5TD"

The sensors use GPS time not UTC. (See page 15 in the link to the manual for proof that the sensors are synced to GPS and not directly to UTC)

And there is a 13 second time difference between GPS and UTC.
According to NIST who oversees UTC :
http://tf.nist.gov/service/acts.htm

"GPS time differs from UTC by the integer number of leap seconds that have occurred since the GPS time scale begam on January 6, 1980. This difference equaled 13 seconds at the end of 2004.The integer-second difference is included in the GPS broadcast message, and is usually applied automatically so that GPS clocks display the same hours, minutes, and seconds as UTC clocks." (that is unless somebody makes an error in setting up the equipment)

Here's the manual for the CNG-5TD:
http://www.ldeo.columbia.edu/LCSN/News/CMG-5TD_Manual_rev_B.pdf#search="CMG-5TD"
on page 21 you see a statement that the synchonizaton to a time standard has to selected.
So there is a possiblity that an installer may have set a wrong option. and the time discrepancy deemed incosequential because the relative difficulty or distance in returning to the sensor site.

As a matter of fact this does occur at times.
This report shows that a systematic timing drift can occur in the CNG-5TD if a power setting in the GPS reciever is incorrectly set.

http://www.ess.washington.edu/SEIS/PNSN/REPTS/Quarterly2003A.pdf#search="CMG-5TD problems"
See page 3 paragraph 3


The 757 used GPS http://www.boeing.com/news/releases/1999/news_release_990429a.html while the ATC used UTC http://www.ntsb.gov/info/ATC _Report_UA93.pdf see page 2


Actually I don't and would be happy to know.
Click to expand...

Happy to oblige:
see above.

But anyhoo. Barring any misadjustments or discrepancies. What is the significance of the 3 min discrepancy?
 
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delphi_ote said:
Before we waste time trying to explain something which seems trivial to me, what do you think the importance of these "missing" minutes is?
Click to expand...

I don't think anything about it. I am (more likely were) just curious about it. Few seconds is reasonble for "clocks sync error" but 3 minutes sounds a lot.

And just for the record; I am trying to DEBUNK this issue. So please feel free to contribute especially if this is trivial for you.
 
uruk said:
notice what the ntsb report also says on page 3:
http://www.ntsb.gov/info/UAL93FDR.pdf
"if the data stream is interupted, sync words will not appear at the proper interval or sequence. and time reference will lost untill the subframe pattern can be established."
The report then goes on to say that 2 additional subframes which are equivalent to one second each was not validated plus an additional subframe which was determined to be a repeat of the previous frame. That's three seconds of uncertainty in the UA93 data log.

Now concerning the Lamont-Doherty siezmic info: (this is a repost of mine from another thread concering LDEO siezmic data).....
Click to expand...

Thanks. But you're still talking about seconds when the error was 3 minutes. See my other replies what is my position now.
Shortly; The Cleveland ATC seems to be myth and seismic-time was corrected which is plausible but somehow I suspect it's not gonna convince CT's.
 
uruk said:
But anyhoo. Barring any misadjustments or discrepancies. What is the significance of the 3 min discrepancy?
Click to expand...
its part of the old "flight 93 was shot down/hit by missile" theories, the FDR and CVR data were truncated to remove evidence of the missile hitting it

of course with the subsequent release of the FDR data and the CVR transcript the argument falls on its face because its clear that nothing is missing
 
uruk said:
But anyhoo. Barring any misadjustments or discrepancies. What is the significance of the 3 min discrepancy?
Click to expand...

If it had been 20-30 minutes I could see having a problem. I had a cousin who was a pilot, it was a hobby for him, mainly small planes including a bi-plane (which he took me up in). At one Thanksgiving he told me about how many people mistakenly assume that if a plane stops functioning it will drop straight down to the ground, to exactly the point below where the engine failed. The point is if United 93 dropped below radar, it may not have gone directly to impact, even if it was in distress (hijackers and passengers & crew struggling for control). Sadly Bud (my cousin) died in a plane crash at an air show about a year after our talk. He was flying a Cesna and was going to drop ping-pong balls out the door for some kids (which they could exchange for prizes), when he experienced engine trouble. He could have landed safely, but would have hit the children below on the runway, so he veered away presumably to land on the rough ground next to it and nosed over. At least that's how understood it.
 
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mcMike said:
I don't think anything about it. I am (more likely were) just curious about it. Few seconds is reasonble for "clocks sync error" but 3 minutes sounds a lot.
Click to expand...
Ah. Just asking questions?
mcMike said:
And just for the record; I am trying to DEBUNK this issue. So please feel free to contribute especially if this is trivial for you.
Click to expand...
So if it's not important, what is there to debunk?
 
Will the missing three minutes be included in the directors cut of United 93? I love extra's on DVD's.
 
One of the delays noted was from a seismic station in New York, correct? I am wondering: How long does it take those seismic waves to travel that far, and did they correct for that? Or, is the time they put down, the time that they recieved a signal?
 
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