Debunked: Mysterious Explosion Before the Flight 11 Crash

Marc Powell

Member
It is claimed by 9/11 conspiracy theorists that the damage and injuries that are documented to have occurred in the base of the World Trade Center North Tower were from a mistimed explosion that went off a few seconds before the impact of Flight 11. As documentation of the mysterious explosion, they present witness statements as well as an audio recording made by an office worker named Ginny Carr at a business meeting in a building near the World Trade Center that morning.

Attached is an audio clip from the recording as presented at the 46:20 mark in the 2014 David Hooper film The Anatomy of a Great Deception (viewable in its entirety at youtube.com/watch?v=l0Q5eZhCPuc ). As can be heard, the audio clip starts with a muffled bang and then about nine seconds later there is another, much louder, bang after which someone at the meeting exclaims, "It sounded like something crashed!" The narrator tells the audience the first bang is the basement explosion and the second is the crash of Flight 11, but that is simply not true. The recording was edited and altered to deceive the audience.

Please compare that version of the Ginny Carr recording with the attached clip taken from the original version available at The September 11 Digital Archive website (00:33 mark at 911digitalarchive.org/items/show/96100 ). In the original recording, the unmistakable whine of jet engines from the approaching plane can be heard for a few seconds before the first bang, and the first bang is much louder than the second. The filmmakers concealed the jet engine sound by narrating over it and they adjusted the sound levels of the two crashing sounds so that the thunderous airplane impact, which is the first bang, seems like only a muted explosion.

Since it takes about nine seconds for an object to free fall from 1,100 feet, the second bang was very likely from debris crashing to the bottom of elevator shafts. So then, the absence of an explosion sound before the plane crash disproves witness reports of an early explosion as being the source of the mayhem in the lobby and basement levels, while the timing of the second bang provides a reasonable explanation for what witnesses may have actually experienced and when they experienced it.
 

Attachments

  • Altered Version of Ginny Carr Recording.mp3
    287.7 KB · Views: 0
  • Original Version of Ginny Carr Recording.mp3
    101.2 KB · Views: 0
Last edited by a moderator:

Oystein

Senior Member
I don't think the second bang was an (or more than one) elevator car. I think it was debris falling outside, to the south of the North Tower. Here is why I think so:

Another sound recording of the crash of AA11 was made by the NYC local news crew of Dick Oliver, WNYW, the local subsidiary of Fox News. They were in front of City Hall, preparing to cover the local primary election that was held in the City that day. The camera was running, but placed on the ground, as the plane approached.
Source: https://www.youtube.com/watch?v=0_CrzPvcY3o


Here is the sequence of audible events, to the second, as I hear them on my headphones:
0:14: Clip begins, some static noise, city hum, voices in the background
0:17: Roar of engines starts to noticeably fade in
0:22: A bumping noise, like something tapping on the microphone
0:23: Loud bang, followed by reverb
0:26: Dick Oliver: "What the hell was that?"
0:28: Sirens start

What I DON'T hear is any particular second bang around 9 seconds (0:32 min) after the first.
Unfortunately, the clip starts barely 9 seconds before the big bang, and so IF there were a lesser bang about 9 seconds before the big one, it might have been just cut off.

The fact that a second bang was audible from Ginny Carr's position but not Dick Oliver's certainly holds clues as to where that second bang may have occurred.

As I said, Oliver's crew was in front of City Hall, on the ground. They almost had a direct view to the North Tower's top (they had to move a few steps to see it), but the direct path to the tower's ground level was blocked by several buildings.
The Ginny Carr meeting, according to the link provided by Marc, took place on the "36th floor of One Liberty Plaza".

The map of the old WTC at Wikipedia shows 1 Liberty Plaza to the right of WTC4 - it's looking over the shorter WTC buildings, and would provide a clear view of St. Nicholas Orthodox Church.
The front landing gear, stuck in an entire WTC perimeter wall panel, had fallen next to that church, as this clip shows:
https://www.cbsnews.com/news/st-nic...d-zero-national-shrine-60-minutes-2020-04-12/
At 3:10 minutes, that assembly is seen and described a few seconds later.
I would assume that this fall would be at least as loud as an elevator car crashing, and, being outside, it would be less muffled.

It is my best guess that the Ginny Carr recording captured that wall panel as it crashed on the ground.
Dick Oliver had the entire WTC and a whole block of other buildings between him and St Nicholas, and that sound would not have traveled all the way to City Hall.
 

Marc Powell

Member
Oystein could very well be right. The WTC 1 panel that landed on Cedar Street smashed a pickup truck and construction scaffolding and probably made a racket that would be clearly heard from Ginny Carr's location less than 1,000 feet away. The main point of my post was that there is no evidence of a mysterious explosion before the plane crash and clear evidence of trickery to make it seem like there was.
 

Jeffrey Orling

Senior Member
I believe workers in the basement witnessed an explosion which somewhere in the sub basement electrical "switch gear" at the base of high voltage electrical risers.
My guess is that the plane hit severed the electrical risers high in the building... it cause a short circuit, but the circuit protection in the sub basement was no "fast enough" and a voltage spike in the sub basement switch gear cause it to explode. This would be at the instant the risers was severed. Electricity travels at almost the speed of light.
The SOUND of the plane hitting the tower would have to travel 1100 through air to reach the ears of the workers in the basement. That would take about 1 second. So observers on the ground would SEE the crash and HEAD it one or more seconds later.

Same phenomena as lighting and thunder. A flash of lightning is often observed BEFORE the sound of the thunder unless the strike is very close to the observer. Normally it is LIGHTNING... interval of time... then thunder. You can compute how far away the strike was by counting seconds and multiply by speed of sound 1,125 feet per second. 5 to 6 seconds means the lightning strike was about a mile away.
 

Marc Powell

Member
I believe workers in the basement witnessed an explosion which somewhere in the sub basement electrical "switch gear" at the base of high voltage electrical risers.
My guess is that the plane hit severed the electrical risers high in the building... it cause a short circuit, but the circuit protection in the sub basement was no "fast enough" and a voltage spike in the sub basement switch gear cause it to explode. This would be at the instant the risers was severed. Electricity travels at almost the speed of light.
The SOUND of the plane hitting the tower would have to travel 1100 through air to reach the ears of the workers in the basement. That would take about 1 second. So observers on the ground would SEE the crash and HEAD it one or more seconds later.

Interesting speculation. However, the lights remained on in the North Tower after the plane crash, so any electrical service disruption it may have caused could not have been too severe. In addition, the physical damage described by survivors in the basement would seem to support the conclusion that additional factors may have been at play. My guess is that the damage and injuries documented to have occurred in the basement levels and the lobby were the result of jet fuel and debris falling down elevator shafts, as well as torqueing of the building frame. By “debris” I am referring to aircraft wreckage, building rubble, elevator cars, counterweights and lift cables, all of which would have seemed like an explosion to anybody nearby as they slammed to the bottom of elevator shafts. The main point is that survivors in the basement were in no position to judge the order of events and what may have been the source of sounds they may have heard. Their testimony is anecdotal and is contradicted by evidence such as the Ginny Carr audio recording and the Dick Oliver video. The doctored evidence in David Hooper’s ironically-titled film gives me the impression that he must have realized that also.
 

Jeffrey Orling

Senior Member
There were 3 sets of risers... one set was severed... upper 1/3 of the tower.
By he way this also caused an explosion in the sub station at the base of 7 wtc when the plane severed/shorted the risers
 

Marc Powell

Member
There were 3 sets of risers... one set was severed... upper 1/3 of the tower.
By he way this also caused an explosion in the sub station at the base of 7 wtc when the plane severed/shorted the risers

You seem to have access to sources of information I am not aware of. Is the information about electrical service risers and electrical faults in one of the NIST report supplements. I must admit I didn't read everything in detail.
 

Jeffrey Orling

Senior Member
You seem to have access to sources of information I am not aware of. Is the information about electrical service risers and electrical faults in one of the NIST report supplements. I must admit I didn't read everything in detail.
The towers were engineered as 3 more or less equal sections of office space. Top has WOW and the observation deck... mech floors at the top and between each section and at the "bottom" above the 7 story lobby. The elevators were set up to be express to the bottom floor or each section with local serving each section. Each section had separate mechanical systems.
 

Marc Powell

Member
The towers were engineered as 3 more or less equal sections of office space. Top has WOW and the observation deck... mech floors at the top and between each section and at the "bottom" above the 7 story lobby. The elevators were set up to be express to the bottom floor or each section with local serving each section. Each section had separate mechanical systems.

I am aware of the arrangement of elevators but have not read anything to inform me about the electrical service feeds for the three zones in each tower. Can you provide a link to that information, to information about service risers being severed by the Flight 11 crash and about electrical faults occurring in the ConEd substation?
 
Last edited:

Jeffrey Orling

Senior Member
It's more than a decade and I don't have the links... but google the design.
I recall that Con Ed's 7WTC Sub station went off line when the plane hit tower one. Con Ed has the ability to have the grid take over for a offline sub station... and that's what they did. You can google that too.

It certainly makes sense that if the WTC 7 sub station went offline when 1WTC was hit... there had to have been a "electrical event" which caused the sub station to go down.

Another thing to note is that in the process of evacuating 7WTC.. elevators were not working. Power was off in the tower and people used the emergency stairs to exit the building. Several people from the flr 23 Emergency Management Center reached ... I believe around floor 7 and witnessed the stairs blown out (explosion on the adjacent mech floor or in the sub station below?). They had to use a different stair at that point to escape the building.

Connect the dots.
 

Marc Powell

Member
Another thing to note is that in the process of evacuating 7WTC.. elevators were not working. Power was off in the tower and people used the emergency stairs to exit the building. Several people from the flr 23 Emergency Management Center reached ... I believe around floor 7 and witnessed the stairs blown out (explosion on the adjacent mech floor or in the sub station below?). They had to use a different stair at that point to escape the building.

The reports I read indicated that power only went out momentarily in WTC 7 when Flight 11 crashed into the North Tower. However, power was lost and emergency generators were brought on line after WTC 2 collapsed. The collapse of the stairs that trapped the last two building occupants actually happened as a result of impact damage from the collapse of WTC 1. I am connecting the dots and I don't see anything that leads me to suspect an explosion of any kind happened in WTC 7 at any time. If you have better information, please let me know about it. Besides, isn't this a bit unrelated to the subject of the original thread?
 

Jeffrey Orling

Senior Member
The reports I read indicated that power only went out momentarily in WTC 7 when Flight 11 crashed into the North Tower. However, power was lost and emergency generators were brought on line after WTC 2 collapsed. The collapse of the stairs that trapped the last two building occupants actually happened as a result of impact damage from the collapse of WTC 1. I am connecting the dots and I don't see anything that leads me to suspect an explosion of any kind happened in WTC 7 at any time. If you have better information, please let me know about it. Besides, isn't this a bit unrelated to the subject of the original thread?
Why would the collapse of 2 WTC cause 7 WTC to loose power?
7 WTC had explosions in the sub station when AA11 hit tower 1
Con Ed replaced the 7 WTC sub station with power from the grid for the region it supplied power to.
Generators provided power at 7WTC for some emergency use for some tenants
There was no power in 1 WTC or 2 WTC after AA11 hit
 

Gamolon

Member
I believe workers in the basement witnessed an explosion which somewhere in the sub basement electrical "switch gear" at the base of high voltage electrical risers.
Jeffrey,

Are the workers you are speaking of William Rodriguez and his co-workers who were in a meeting when the plane hit or were they a different set of workers located somewhere else in the sub basement you are referring to?
 

Gamolon

Member
I believe so
I don't believe William was a witness to an explosion. His initial description of his encounter is below. He had given it during an interview the day of the attacks:

RODRIGUEZ: I was in the basement, which is the support floor for the maintenance company, and we hear like a big rumble. Not like an impact, like a rumble, like moving furniture in a massive way. And all of sudden we hear another rumble, and a guy comes running, running into our office, and all of skin was off his body. All of the skin.

https://transcripts.cnn.com/show/bn/date/2001-09-11/segment/24

The first rumble very well may have been the impact propagating through the building or even the freight elevator crashing through the shaft as it descended. The second rumble could have been the fireball exiting the shaft and burning the guy that was mentioned.

In any case, William's initial eyewitness description above is WAY different than what he eventually describes as his "conspiracy fame" grew and he attended presentations and conferences to discuss his experience. I believe he embellished his experience from "a rumble, like moving furniture in a big way" to "an explosion that lifted him and others off the floor and caused pieces of the ceiling to fall on them".

Just my thoughts.
 

Marc Powell

Member
Why would the collapse of 2 WTC cause 7 WTC to loose power?
7 WTC had explosions in the sub station when AA11 hit tower 1
Con Ed replaced the 7 WTC sub station with power from the grid for the region it supplied power to.
Generators provided power at 7WTC for some emergency use for some tenants
There was no power in 1 WTC or 2 WTC after AA11 hit

Please read NCSTAR 1-9, Appendix A for a full history of events in the ConEd substation. It should answer your questions and clear up any misunderstandings you have.
 

JMartJr

Senior Member
In any case, William's initial eyewitness description above is WAY different than what he eventually describes as his "conspiracy fame" grew and he attended presentations and conferences to discuss his experience. I believe he embellished his experience from "a rumble, like moving furniture in a big way" to "an explosion that lifted him and others off the floor and caused pieces of the ceiling to fall on them".
Whether driven by making the story better for a conspiracy-believing audience, or simply by the normal ways in which memories mutate over time, a good reminder of the limits of the usefulness of eye-witness testimony as evidence. Heck, for all of me he may have been in shock arly on and reporting inaccurately, only to become more accurate later. Bu we can't KNOW which point n the evolution of his story might represent the best accurate description of events, which to me means "Be careful about using any of it, always check back with the physical evidence."
 

Gamolon

Member
Why would the collapse of 2 WTC cause 7 WTC to loose power?
7 WTC had explosions in the sub station when AA11 hit tower 1
Con Ed replaced the 7 WTC sub station with power from the grid for the region it supplied power to.
Generators provided power at 7WTC for some emergency use for some tenants
There was no power in 1 WTC or 2 WTC after AA11 hit
I was reading here:
http://www.historycommons.org/entity.jsp?entity=con_edison_1

There was no fire or significant damage reported by mechanics who were at the sub station around the time of the impact until about 10:20am when the building was evacuated.

Also, the article says that "two auto/open feeders" tripped due to collateral damage from the first impact and the computers rerouted the power, which is why the lights went off in WTC7 and came back on after a few seconds.

Is there a difference between a circuit breaker and an auto/off feeder?
 

Mauro

Active Member
Is there a difference between a circuit breaker and an auto/off feeder?

A feeder circuit is, by definition (UL508A), all what lies upwards of the last overcurrent protection device, that is to say, all the wirings upwards of the last circuit breaker (or fuse). It's often intendend as meaning the connection coming from the power sub-station, into, say, a building distribution panel. I have never heard before of an open/auto feeder as reported in the Con Edison reference, nor I can find anything by googling it. I assume they mean the overcurrent protection devices of the power sub-station, which are analogous to circuit breakers in function, even if they can get much bigger:
It's not really uncommon for an upwards overcurrent protection device to trip instead of the lower-rated downward one, even with an 'ordinary' short-circuit (*), anything could happen with a 9/11 style accident. Electric distribution networks are also often unstable in fault conditions, with the tripping of a protection device causing more devices to trip which in turn trip even more (this is how the big black-outs happen, not that this happened on 9/11).

(*) yeah, this should't happen.. but it happens :)
 
Last edited:

Oystein

Senior Member
I downloaded the Ginny Car audio, opened it with "Audacity", a simple sound mixing software, located the two wave form peaks corresponding to the two bangs, and thus determined the time interval between them:
9.3 seconds - give or take a few 1/100s of a second (where do you start and stop the clock? The sound events are blurred over 0.1 to 0.2 seconds)
GinnyCarrRecording_2Bangs_WaveForm.jpg

The impact of AA11 occurred between floors 93 and 99, so let's say center/fuselage/front landing gear at 95th to 96th floor. That would be about 360 m = 1180 ft (Height of tower: 415 m divided by 110 floors, times 96 floors = 362 m - landing gear and somewhat downward trajectory would make this tend a little lower) high.

Freefall from 360 m would take t = SQRT(2*360 m/g) = 8.57 s. I am not going to calculate air resistance and resulting added time for a WTC wall panel - shape too complex. Just going to say it will slow the fall a bit, but not much. 8.9 s? Something like that.

Next bit of work will be to calculate the distances from the 36th floor of 1 Liberty Plaza to both the 96th floor of the North Tower and the spot near St. Nicholas where that panel landed, and to calculate how long sound travels to Ginny Carr's location from either location.
 

Oystein

Senior Member
But first some analysis of the Dick Oliver tape. Because I think I DID hear a second "bang" after all!
Because this post is lengthy, first a summary:

  1. I think I detect a second, faint "bang" sound 10.9 seconds after the plane crash sound.
  2. If this is the same 2nd "bang" that Ginny Carr recorded 9.3 seconds later, we might be able to calculate plausible locations for the origin
  3. There is a glitch in the video image at 21 seconds in the Dick Oliver, followed a small fraction of a second later by a "bump" sound.
  4. That bump sounds occurs 1.4 seconds before the plane crash sound
  5. I believe the bump and the glitch are both the result of the plane crash disturbing the video data transmission to the news studio, where the film was most likely recorded.
Alright, on with the evidence:

I grabbed the audio (first ca. 43 seconds) from this YouTube:
Source: https://www.youtube.com/watch?v=0_CrzPvcY3o




All my time stamps are relative to this MP3.

Again, I ran that file on Audacity, a lowly software for audi mixing, to time-stamp wave-forms.
The plane and the first crash are pretty straightforward:

DickOliverVideo_PlaneApproaches.jpg

You see the noise swell from approximately 17.5 seconds to 21.75 seconds - at which time there is a bumping noise - I'll come to that later. After that, recording level is lower, until the big bang at 23.1 seconds and its reverb:

DickOliverVideo_FirstBang.jpg

Then the tape rolls on, and from 33 to 35 seconds, Oliver says: "That was the reaction on the part of the..." (and never finishes that sentence)

DickOliverVideo_ThatWasTheReactionOnThePartOfThe.jpg

And I THINK right there at 34.0 seconds, that feature (highlighted)...
DickOliverVideo_SecondBang.jpg
....is a "bang".

To make things a little clearer, I slowed that audio down by a factor of 2, and I think now the "bang" near the end of the word "reaction" is more distinct:


This second bang occurs just after the 34 seconds mark - 34.025 maybe. (It's really difficult to synchronize in your head what you hear and what you see; I just selectively canceled various bits of about 0.1 seconds duration, to see which feature, when missing, makes the bang go away, and that what I highlighted was it).

Soooo, the time interval between the big and the tiny bang is 23.1 to 34.02 s, or 10.9 seconds duration.

----

Again, on the Ginny Carr recording, the interval was 9.3 seconds. This difference would almost allow us to triangulate where the second bang occurred, given the (approximately) known positions of Carr, Oliver and the North Tower 96th floor.

---

Now coming back to the bump noise at 21.7 seconds. I thought this is a tap on the microphone, but maybe it isn't, as a fraction of a second before that bump, there is also a glitch in the video image:

DickOliverVideo_Glitch.jpg

It has been speculated, with good reason (though I haven't looked up any sources yet - I just remember), that the glitch was caused by the plane crash momentarily disturbing the video signal path from the mobile news crew to the news station, as most broadcasters at the time made use of the North Tower's antenna mast.

I again selectively deleted (muted) small bits of of the audio until I found the shortest interval that, when muted, made the "bump" go away. It's this (highlighted), starting 21.69 s, duration 0.075 seconds:
DickOliverVideo_Bump.jpg

Now, if I zoom into that with Audacity, I get this image:
DickOliverVideo_BumpZoomed.jpg

It appears that the signal is "poorer", less dense, in and closely around that "bump" interval, which may simply mean data loss. This makes sense if the video was recorded not by the camera but by the studio.

Now, the audio glitch (bump) starts just before 21.7 seconds, the plane crash sound is recorded at 23.1 seconds - 1.4 seconds for sound to travel from 96th floor to Dick Oliver's team, or about 480 meters (given that sound of speed is 343 m/s). It should be easy to verify this value is not too far off. True distance may be a little off, as the data link disturbance probably started a liiiiittle after the crashing sound first was generated.
 

Marc Powell

Member
Why? I shared as much as I need to...
Opinions do not count as evidence and can be dismissed.
The impact of AA11 occurred between floors 93 and 99, so let's say center/fuselage/front landing gear at 95th to 96th floor. That would be about 360 m = 1180 ft (Height of tower: 415 m divided by 110 floors, times 96 floors = 362 m - landing gear and somewhat downward trajectory would make this tend a little lower) high.

Freefall from 360 m would take t = SQRT(2*360 m/g) = 8.57 s. I am not going to calculate air resistance and resulting added time for a WTC wall panel - shape too complex. Just going to say it will slow the fall a bit, but not much. 8.9 s? Something like that.

Next bit of work will be to calculate the distances from the 36th floor of 1 Liberty Plaza to both the 96th floor of the North Tower and the spot near St. Nicholas where that panel landed, and to calculate how long sound travels to Ginny Carr's location from either location.
I like the direction your calculation is taking. I went ahead and calculated the straight line distance between where the WTC 1 panel landed on Cedar Street and the center of the west face of the 36th floor at 1 Liberty Plaza to be 940 feet. With a speed of sound of 1,100 feet per second, it would take approximately 0.9 seconds for the sound of the panel hitting the ground (and pickup truck/construction scaffolding) to reach Ginny's position. The straight line distance between the center of the north face of the 96th floor of the North Tower and the center of the west face of the 36th floor at 1 Liberty Plaza is approximately 1,250 feet. So, it would take approximately 1.1 seconds for the sound of the airplane impact to reach Ginny's position. Then, adding the 0.2 second difference between the time lag for Ginny hearing the first event (plane crash) and the time lag for her hearing the second event (panel ground impact) to the panel fall time of 8.9 seconds, we get 9.1 seconds. That is pretty damn close to the 9.3 seconds you measured from the Audacity wave form chart. From all that, I am convinced that the second bang on the Ginny Carr recording is from the ground impact of the wall panel. The crashing of falling elevator equipment would have taken place at about the same time as the crashing of the wall panel and would have been heard by Ginny at nearly the same time. However, it would have been heavily muffled and possibly concealed by the panel crash sound and by background noise on the tape recording.

The question one should be asking is why David Hooper did not perform a calculation like this to confirm what actually caused the sounds on Ginny Carr's tape recording and why he and his Technical Director (Richard Gage) could have had the audacity to assume that their deceptive manipulations of the recording would not be challenged.
 
Last edited:

Oystein

Senior Member
So, let's account for the speed of sound.

I determined the position of the Dick Oliver crew on the side walk of Park row, next to City Hall Park, as best as I could, by looking at the Woolworth Building, and how they could see the North face of the North Tower to the left of the Woolworth.
As for Ginny Carr, I assume they must have been at the West face of One Liberty Plaza, as they apparently had a view of the WTC.
I assume the source of the first crash sound was the center of the North face of the North Tower.
The wall panel that fell near St. Nicholas church must have been a little closer to West St. than today's St. Nicholas, as it hat to fall clear West of the South Tower, but I did not make much of an effort to pin that location down.

And so, I used the "measure distance" feature of Google Maps to determine the approximate horizontal distances from both recorders to both presumed "bang" sources:
DickOliver_DistanceToWallPanel.jpgDickOliver_DistanceToWTC1.jpg
GinnyCarr_DistanceToWallPanel.jpgGinnyCarr_DistanceToWTC1.jpg

These distances are, in meters (rounded to the nearest 5 meters):
Dick Oliver -> Wall Panel = 645 m
Dick Oliver -> WTC1 = 550 m
Ginny Carr -> Wall Panel = 245 m
Ginny Carr -> WTC1 = 310 m

Impact height at WTC1 was, as established earlier, about 360 m high
36th floor of One Liberty Plaza - roof is 226 m high, building has 54 floors, it appears that there is a mechanical top, maybe 3 floors high, that is probably not included in the floor count, so let's say it is 59 floors high to the roof. 36th floor is then at 226 m * 36/59 = 138 m
Dick Oliver and ground near St. Nicholas I assume to be at 0 m - i.e. level with the ground of both WTC1 and OLP.

Now let's apply some Pythagoras (d^2 + h^2 = td^2) to figure out true distances (td):

Dick Oliver -> Wall Panel = 645 m
Dick Oliver -> WTC1 = 657 m
Ginny Carr -> Wall Panel = 281 m
Ginny Carr -> WTC1 = 381 m

And finally, applying a speed of sound of 343 m/s, this is the resulting delays:

Wall Panel ->Dick Oliver = 1.88 s
WTC1 -> Dick Oliver = 1.92 s
Wall Panel -> Ginny Carr = 0.82 s
WTC1 -> Ginny Carr = 1.11 s

Both were closer to the wall panel than the impact site in the WTC1 wall, but Oliver only by 0.04 s sound runtime, while the difference is 0,29 s for the Ginny Carr party. The difference between the two recording locations would thus be only 0.25 s.

The fall time of the wall panel, judging from this and the Ginny Carr recording, would be 9.3 s (measured between sounds in recording) plus 0.3 s = 9.6 s. That's a full second longer than freefall in vacuum. Perhaps I need to calculate a fall in air after all?

These results are quite a bit more off from my predictions than I had expected. My measured differential was 1.6 seconds (Ginny Carr: 9.3 s; Dick Oliver: 10.9 s). Maybe the bang I hear in Oliver's tape isn't a "bang", or a third "bang". Or that 2nd "bang" sound took such a long detour (as there were buildings in the way) to account for the extra 1.35 s.
 

Oystein

Senior Member
Whoops, I had not refreshed before posting my own calculation for sound propagation. Saw your post only after posting mine
...I went ahead and calculated the straight line distance between where the WTC 1 panel landed on Cedar Street and the center of the west face of the 36th floor at 1 Liberty Plaza to be 940 feet. With a speed of sound of 1,100 feet per second, it would take approximately 0.9 seconds for the sound of the panel hitting the ground (and pickup truck/construction scaffolding) to reach Ginny's position. The straight line distance between the center of the north face of the 96th floor of the North Tower and the center of the west face of the 36th floor at 1 Liberty Plaza is approximately 1250 feet. So, it would take approximately 1.1 seconds for the sound of the airplane impact to reach Ginny's position. Then, adding the 0.2 second difference between the time lag for Ginny hearing the first event (plane crash) and the time lag for her hearing the second event (panel ground impact) to the panel fall time of 8.9 seconds, we get 9.1 seconds. That is pretty damn close to the 9.3 seconds you measured from the Audacity wave form chart. ...
You should be subtracting 0.2 s from the actual panel fall time (whether my gut-feeling 8.9 s, or the freefall-in-vacuum 8.6 s), for the second bang comes from closer, and thus is expected to arrive earlier, relative to the first. 8.7 s / 8.4 instead of 9.3? Close, but not close enough.
I really have no idea how much air resistance would slow down such a wall panel.

Also, it would take longer for AA11 and its debris to travel all the way through the tower and finally break lose that wall panel to initiate its fall then for the sound to travel the same distance. And I could not confidently estimate that. I'll try anyway:
According to Wikipedia, AA11 traveled at "404 knots (465 mph; 748 km/h)" when it impacted. That's 208 m/s, or 60.6% of the sound of speed.
Upon impact, everything would slow down in collisions, until finally some of that debris hit the wall on the other side with some residual velocity. Shall we say 1/3 of original velocity? Then that mass would have traveled at an average of 2/3 of original velocity, or 40% of the speed of sound, make that 137 m/s.
The tower was 63 m wide/deep. The debris would have taken 63/137 s = 0.46 s to traverse it, while sound would have taken 63/343 s = 0.18 s (through the air in the offices - I am not considering that some of the sound would travel faster through the steel, albeit at a detour along the spandrels). That's a difference of about 0.3 s, that we would have to add to the expected time interval between two the bangs.

To recap:
On the audio, we measure 9.3 seconds. Accounting for the difference in distance and sound propagation time, the time between aircraft impact and wall panel landing would have been closer to 9.6 s. But as the fall is delayed by 0.3 seconds relative to sound propagation, actual fall time works out to be closer to 9.3 s after all.
 

Oystein

Senior Member
On the Dick Oliver reel, I had measured the time from "glitch bump" to onset of plane impact sound as 1.4 s, while the simple distance from impact location to Oliver's position would result in 1.9 s from actual impact to sound of impact.

I computed in #29 that the debris might take half a second to traverse the entire tower depth.
I'd assume that disruption of the signal broadcast via antenna mast would be caused by debris affecting infrastructure (or structure) in the core, so sooner than the 0.5 s till exit. More like 0.2 seconds?
I then still have a couple or three tenths of a second to account for, to explain the difference between 1.4 s and 1.9 s.
Best I can think of at the moment is that maybe the data stream was entirely interrupted for a couple of thenths of a second, 10 or so frames never got transmitted to the studio.
 

Marc Powell

Member
You should be subtracting 0.2 s from the actual panel fall time (whether my gut-feeling 8.9 s, or the freefall-in-vacuum 8.6 s), for the second bang comes from closer, and thus is expected to arrive earlier, relative to the first. 8.7 s / 8.4 instead of 9.3? Close, but not close enough.
I really have no idea how much air resistance would slow down such a wall panel.
I was working too fast and got it wrong. Of course, the 0.2 seconds should be subtracted from the fall time, not added to it. Even so, as you pointed out, with all the unknown factors and loose estimations involved in the calculation, it is entirely plausible for the second bang to have been the ground impact of the wall panel.
 

Keith Beachy

Senior Member
Everyone has already talked about the speed of sound in steel vs air, I suspect 5800 m/s vs 340 m/s. Thus in the basement of the WTC, there would be a giant "BANG" at impact less than 1/10 of second, vs the sound of impact and jet about a second later. Plus falling junk... etc
 

Marc Powell

Member
Everyone has already talked about the speed of sound in steel vs air, I suspect 5800 m/s vs 340 m/s. Thus in the basement of the WTC, there would be a giant "BANG" at impact less than 1/10 of second, vs the sound of impact and jet about a second later. Plus falling junk... etc
You are right. There were a lot of sounds being heard at different times and a lot of high-energy events going on in the basement immediately after the plane crash. Maybe survivors were confused by the sound of the plane crash transmitted through the steel followed about a second later by its sound transmitted through air followed a few seconds after that by the crashing of falling debris and the exploding of jet fuel. However, there is no evidence of any bang having been heard as early as nine seconds before the plane crash bang(s) which is the contention of the claim being debunked.
 
Thread starter Related Articles Forum Replies Date
Whitebeard Debunked: Nibiru FOUND? Mysterious gigantic rogue planet spotted lurking outside our solar system Science and Pseudoscience 1
Eden Debunked: Mysterious/Alien Pyramid inside Area 51/NTS/NNSS Conspiracy Theories 20
Mick West Debunked: Chemwebs / Mysterious Fibers fall from sky (ballooning spiders) Contrails and Chemtrails 75
Marc Powell Debunked: 9/11 truth experts are knowledgeable professionals and their judgments are to be trusted 9/11 24
Marc Powell Debunked: Explosions preparatory to demolition of the WTC North Tower are visible as Flight 175 crashes into the South Tower 9/11 7
Mick West Debunked: Pfizer Developing a Twice-Per-Day COVID Pill, Taken Alongside Vaccines Coronavirus COVID-19 0
Marc Powell Debunked: Demolition “squib” is visible at top of WTC North Tower before Flight 11 crash 9/11 12
Marc Powell Debunked: Construction worker Philip Morelli experienced an explosion in the sub-basement of the North Tower 9/11 0
Marc Powell Debunked: ABC News correspondent George Stephanopoulos reported an explosion in the subway 9/11 1
Marc Powell Debunked: Debris from twin towers was projected upward by explosives 9/11 13
Marc Powell Debunked: Government officials revealed having foreknowledge of Building 7’s collapse 9/11 58
Marc Powell Debunked: NIST computer simulation of Building 7 collapse is inaccurate 9/11 22
Marc Powell Debunked: FEMA reported finding evidence that steel had melted. 9/11 47
Marc Powell Debunked: VP Dick Cheney ordered a standdown of jet fighters on 9/11 9/11 16
Oystein Debunked: Claim that Bobby McIlvaine's injuries ("lacerations") are best explained as result of glass shards and debris from bombs 9/11 20
Marc Powell Debunked: World Trade Center should not have collapsed due to 9/11 fires 9/11 3
Marc Powell Debunked: Firefighter reports of secondary explosions 9/11 3
Marc Powell Debunked: Steel was hurled hundreds of feet by explosives 9/11 4
Marc Powell Debunked: Demolition Explosion Before Collapse of South Tower 9/11 2
Marc Powell Debunked: Explosion in South Tower Lobby 9/11 5
J.d.K Debunked: Marx: "The classes and the races too weak to master the new conditions must give way... They must perish in the revolutionary Holocaust" Quotes Debunked 0
dimebag2 Poll : Which DOD Navy video do you consider debunked ? UFO Videos and Reports from the US Navy 41
Mick West Debunked: Diving Triangle UFO Photos from Reddit [Fake] UFOs and Aliens 37
Theferäl [Debunked] Object Seen From Airplane Above Canberra: 04 Apr 2012 Skydentify - What is that Thing in the Sky? 5
TEEJ Debunked: Claim that Joe Biden's hand passes through microphone during White House press gaggle, 16th March 2021 Election 2020 8
bird_up Debunked: "Interdimensional being" caught on CCTV in Neza, Mexico Ghosts, Monsters, and the Paranormal 6
M Debunked: Atmospheric pressure on Mars is 9 PSI, not 0.09 PSI as claimed by NASA Science and Pseudoscience 75
Patrick Gonzalez Debunked: missing cable on Perseverance landing footage proves it is fake. General Discussion 3
TEEJ Debunked: Biden's Oval Office "Coming Apart at the Seams" [It's a Door] Election 2020 19
derrick06 Debunked: UFO over California Highway (TMZ) UFOs and Aliens 1
P Debunked: 7 Alleged photos of aliens UFOs and Aliens 9
Mick West Debunked: Biden signing "Blank" Executive Orders Election 2020 5
Mick West Debunked: Biden in "Fake" Oval Office Election 2020 27
P Debunked: UN hidden camera: the first UFO contact happened [Deep Fake] UFOs and Aliens 3
Mick West Debunked: 94% of Fulton County Ballots Manually Adjudicated [It's a Process all Batches go Through] Election 2020 0
Mick West Debunked: "Missile Strike" caused Nashville Explosion General Discussion 3
Mick West Debunked: Nashville Explosion was "Across the Street" from the RV General Discussion 0
Mick West Debunked: "Error rate of 68.5% Allowable is .0008%" [Neither is True] Election 2020 4
Mick West Debunked: Claim that the Electoral College Count On Jan 6 will Change the Election Election 2020 136
Rory Debunked: Einstein wrote "blind belief in authority is the greatest enemy of truth" Quotes Debunked 12
Mick West Debunked: Navid Keshavarz-Nia's Claims of "A Sudden Rise in Slope" as Election Fraud Evidence Election 2020 5
Mick West Debunked: Trump's Claim of "1,126,940 votes created out of thin air" in PA Election 2020 8
Mick West Debunked: Crowder's "Fraud Week" Title Graphic (and Why it Matters) Election 2020 1
JFDee Debunked: Democratic senators complained about 'vote switching' by Dominion voting machines in 2019 Election 2020 2
Mendel Debunked: The Democrats are trying to take away freedom of religion Election 2020 6
H Debunked: Dr. Shiva's Scatterplot Analysis of Michigan Precincts Election 2020 43
Mick West Debunked: Suspicious "Biden Only" Ballots in Georgia Election 2020 3
Mick West Debunked: "Nancy Pelosi's long time Chief of Staff is a key executive at Dominion Voting" Election 2020 0
Mick West Debunked: Wisconsin Turnout 89% Impossible High [Actually 72%] Election 2020 1
Mick West Debunked: Video of Poll Worker "Filling In" Ballots. Election 2020 3
Related Articles


















































Related Articles

Top