Flight 77 obstacles

[Dave Rogers]

I'm starting this thread to try and salvage some rational discussion from the thread "The Final Word : Flight 77 Did Not Hit The Pentagon FDR proves it" that just got sent to AAH. I'm doing this because I feel TC329's original post raised a new claim that hasn't been discussed in detail here before, and that there was some useful discussion of it in the thread. Note that this isn't intended to be yet another discussion of the FDR data in general, but a thread specifically on whether the Flight 77 path is consistent with known obstacles in the vicinity of the Pentagon.

Chillzero asked that I make clear that:

• We've discussed starting a new thread on this,
• It's a new discussion point not already covered, and,
• Any incivility, bickering or off-topic posting will result in the thread being set to moderated status.

The OP referred to the page:
http://pilotsfor911truth.org/descent_rate031308.html
and makes the claims that:
(1) Flight 77's path took it over the 169ft VDOT antenna;
(2) Flight 77 therefore had to sustain a 4480fpm descent rate to strike the lightpoles on Washington Blvd.
(3) To arrest this descent prior to striking the Pentagon would require a 30.1G pullout (note that the website referred to does not assert this, rather it claims 11.2G)
(4) This is unsustainable by the airframe.

If TC329 would like to correct or clarify his original claims, that would seem appropriate to me. Any important points that were made in the original thread can be reposted in this one by the original posters by copying and pasting if they wish; I'd like to recover them for the forum if possible.

Everyone OK with that? Let's see where we got to.

Dave

 

[TC329]

I'm starting this thread to try and salvage some rational discussion from the thread "The Final Word : Flight 77 Did Not Hit The Pentagon FDR proves it" that just got sent to AAH. I'm doing this because I feel TC329's original post raised a new claim that hasn't been discussed in detail here before, and that there was some useful discussion of it in the thread. Note that this isn't intended to be yet another discussion of the FDR data in general, but a thread specifically on whether the Flight 77 path is consistent with known obstacles in the vicinity of the Pentagon.

Chillzero asked that I make clear that:

• We've discussed starting a new thread on this,
• It's a new discussion point not already covered, and,
• Any incivility, bickering or off-topic posting will result in the thread being set to moderated status.

The OP referred to the page:
http://pilotsfor911truth.org/descent_rate031308.html
and makes the claims that:
(1) Flight 77's path took it over the 169ft VDOT antenna;
(2) Flight 77 therefore had to sustain a 4480fpm descent rate to strike the lightpoles on Washington Blvd.
(3) To arrest this descent prior to striking the Pentagon would require a 30.1G pullout (note that the website referred to does not assert this, rather it claims 11.2G)
(4) This is unsustainable by the airframe.

If TC329 would like to correct or clarify his original claims, that would seem appropriate to me. Any important points that were made in the original thread can be reposted in this one by the original posters by copying and pasting if they wish; I'd like to recover them for the forum if possible.

Everyone OK with that? Let's see where we got to.

Dave

Where did my thread go?

Why was it moved/deleted?

 

[boloboffin]

Where did my thread go?

Why was it moved/deleted?

This is a question more appropriate for Forum Management. Please discuss the substance of your claim here.

 

[Totovader]

I feel it necessary to repost my observation: The FDR found at the Pentagon is supposed to prove that no plane hit the Pentagon???

I'm still waiting for some conspiracist to explain that one to me. Until then- this entire line of reductio ad absurdum is moot.

 

[Dave Rogers]

Where did my thread go?

Why was it moved/deleted?

The thread was sent to Abandon All Hope because the signal to noise ratio was getting negligible. I started the new thread because I felt your original post contained a point worth discussing, and I'd like to recover the signal without incurring the noise. In line with that, I'm inviting you to re-state the original claim.

Dave

 

[Dave Rogers]

I feel it necessary to repost my observation: The FDR found at the Pentagon is supposed to prove that no plane hit the Pentagon???

I think TC329's choice of title was a little misleading. The topic here is whether Flight 77 overflew the VDOT antenna before striking the light poles, and, if so, whether this was a physical impossibility. As such, it doesn't rely on the FDR for confirmation.

Dave

 

[TC329]

The thread was sent to Abandon All Hope because the signal to noise ratio was getting negligible. I started the new thread because I felt your original post contained a point worth discussing, and I'd like to recover the signal without incurring the noise. In line with that, I'm inviting you to re-state the original claim.

Dave

Based on this topography combined with the height of the VDOT Antenna protruding into the reported flight path of American 77, it is aerodynamically and physically impossible for this aircraft to have performed the way the government would have us believe.​

Top of VDOT Height = 304 MSL (above sea level)
Top of Pole 1 height = 80 MSL

Difference = 224 feet descent required.

Distance between VDOT - Pole 1 = 2400 feet

2400/Speed 781 feet per second (according to Flight Data Recorder) = 3 seconds

224/3 seconds = 75 fps descent rate x 60 = 4480 fpm descent rate needed to reach top of pole 1 from top of VDOT Antenna.

Pole 1 distance to Pentagon = 1016 feet

1016 feet/781 fps = 1.3 seconds

4480 fpm descent needs to be arrested within 1.3 seconds.

75 * 1.3 = 97.5 foot descent within 1.3 seconds.

97.5/32 fps accel due to gravity = 3.0 G's + 1 G = 4.0 G's needed to arrest descent within 1.3 seconds and 97.5 feet vertically. However, 97.5 feet vertically is not available.

Top of pole 1 height = 80 MSL
"Impact hole" height = 33 (pentagon ground level) + 12 feet (center of pentagon hole height) = 45 MSL

80 feet (top of pole 1) - 45 (height of "impact hole") = 35 feet vertically available to arrest descent rate of 4480 fpm.

97.5/35 = 280% (G Load required to arrest 4480 fpm descent rate within 1.3 seconds and 97.5 feet vertically needs to be increased by 280%.)

280% x 4.0 G's = 11.2 G's needed to arrest descent.

Conclusion = Impossible for any transport category aircraft to descend from top of VDOT Antenna to top of pole 1 and pull level to "impact hole" as reported by the government story and seen in the DoD "5 Frames Video". 11.2 G's was never recorded in the FDR. 11.2 G's would rip the aircraft apart.

This does not account for response time to initiate the arrest. Increased time is needed or higher altitude at pentagon in order to be within aircraft structural limits, or higher peak G loads. The VDOT Antenna was present on September 11, 2001, and was not struck by any object.
Transport Category aircraft are limited to 2.5 G's positive and 1.0 negative. Although there is a margin of error built into these limits, it is not anywhere near 448% or 11.2 G's positive. Aerobatic Category Aircraft have a positive G load limit of 6.0 G's. Some may argue that the flight path "just missed" the VDOT Antenna, in which case we also worked out the numbers if the aircraft were at ground level at the antenna. The G loads required would be ~4.3 G's. Still excessive for a transport category aircraft. Not to mention the aircraft certainly was not at ground level abeam the Navy Annex and such G loads were never recorded in the Flight Data provided by the NTSB. Feel free to input the numbers yourself using above calculations as a guide and ground elevation of antenna.

 

[CurtC]

The analysis he linked to at the PfT site bizarrely assumes that after 77 passed over the tall antenna, it continued at a constant, straight-line descent rate until it hit the first light pole a half-mile later, and only at that moment did it start to level off - the slope from the light pole to the Pentagon's wall is a much shallower descent rate. Balsamo's idiotic reasoning is that a plane couldn't pull out of a 4500 ft/min descent when it's only 40 feet off the ground.

Well, yeah, but that's a ridiculously idiotic flight path that he's proposed, so his showing that it's mathematically impossible just rules out that one possibility. If Rob can't immediately see the problem with his proposed path, he's beyond help. It scares me to think that people's lives depended on his gray matter back when he flew commercially.

 

[Anti-sophist]

I can't wait to get home and put this into my spreadsheet. I'll add the new data point and let ya'll know what g-forces would actually be required. Should be fun.

Here's the original:





I do notice one missing piece of this puzzle though: Have "we" actually established that the plane went _over_ this antenna as opposed to around it?

 

[Dave Rogers]

Some may argue that the flight path "just missed" the VDOT Antenna, in which case we also worked out the numbers if the aircraft were at ground level at the antenna. The G loads required would be ~4.3 G's.

This is the biggest problem I have with the whole analysis.

I checked the alignment of the flight path on Google Earth, and it actually passed about 60 feet from the antenna. Given that the wingspan of a 757 is 124 feet, even this flight path only indicates that the wingtip could have clipped the antenna had it been low enough. An error of two feet in the right direction means that the plane would have missed the antenna. The flight path can't be known to this resolution. Therefore there is no reason to believe that flight 77 had to fly over the antenna.

Let's assume therefore that the flight path missed the VDOT antenna, which is not contradicted by the data. That means that we have no information concerning the altitude of the plane as it passes the antenna, so there's no reason it can't have been descending at a constant rate from the antenna, through striking the light pole, up to the point of impact. We don't even know the altitude at the first light pole impact, only that it's less than the pole height. Therefore there's no information to determine the vertical profile of the course, since there's only one data point to fit to. All we know is that in the final part of its course Flight 77 went from less than 80 feet above MSL to 45 feet above MSL.

Dave

 

[Myriad]

Oh, this is rich. Even using Rob Balsamo's absurd assumptions about the flight path, the maneuver is still possible. His calculations are simply wrong!

Let's start with this part here:

Pole 1 distance to Pentagon = 1016 feet

1016 feet/781 fps = 1.3 seconds

4480 fpm descent needs to be arrested within 1.3 seconds.

75 * 1.3 = 97.5 foot descent within 1.3 seconds.

97.5/32 fps accel due to gravity = 3.0 G's + 1 G = 4.0 G's needed to arrest descent within 1.3 seconds...

Ummmm, no. Arresting a 75 fps descent within 1.3 seconds requires arresting 75/1.3 = 57.7 feet per second of velocity, per second. He's multiplied where he should have divided.

(To confirm that multiplying is wrong, imagine that the plane has 100 seconds to arrest its descent, and repeat Rob's calculation. Now the G forces needed will be 235 G's! Perhaps it would make more sense if more time to level off meant less G forces?)

So let's correct this:

Pole 1 distance to Pentagon = 1016 feet

1016 feet/781 fps = 1.3 seconds

4480 fpm (75 fps) descent needs to be arrested within 1.3 seconds.

75 / 1.3 = 57.7 fps decrease in descent rate per second.

57.7/32 fps accel due to gravity = 1.8 G + 1 G = 2.8 G's needed to arrest descent within 1.3 seconds...

Now, for the next step:

...and 97.5 feet vertically. However, 97.5 feet vertically is not available.

What is this figure of 97.5 vertical feet? That's the distance the plane would descend at 75 fps in 1.3 seconds, if it were not accelerating upward. Since we've just determined that it is accelerating upward at 1.8g (based on the assumption that it has to have leveled off by the time it reaches the Pentagon wall), how far would it actually descend?

That can be determined from the distance formula for an accelerating object, distance = v(initial)*t + 1/2*a*t^2. Since we have positive distance being downward, the a term will be negative because the acceleration is upward. Plugging in the values of

t = 1.3 sec
v(initial) = 75 fps
a = 32*1.8 = 57.6 fps per second, we get

distance = 97.5 - 48.7 = 48.8

(In other words, with rounding error, half the 97.5 foot (v(initial) * t) distance, what we would expect from constant acceleration to zero velocity.)

So, is 49 feet vertically available?

Top of pole 1 height = 80 MSL
"Impact hole" height = 33 (pentagon ground level) + 12 feet (center of pentagon hole height) = 45 MSL

80 feet (top of pole 1) - 45 (height of "impact hole") = 35 feet vertically available to arrest descent rate of 4480 fpm.

However, as R. Mackey pointed out on the previous thread, it's the bottom of the wings that must clear the tower and hit the pole, so we should be measuring the descent to the wing-bottom level of the hole in the Pentagon. That's about 7 feet from the Pentagon ground level, or 40 feet msl, or (80-40) = 40 feet descent from the light pole. Oops! We need 49 feet, we're not going to make it.

So, we need to pull up faster. Pulling up at 2.1 G (so the total G force on the plane is 3.1 G) makes up that 9-foot difference in position and lines us up with the impact hole.

t = 1.3 sec
v(initial) = 75 fps
a = 32*2.1 = 67.2 fps per second, we get

distance = 97.5 - 56.8 = 40.7, close enough to be within the calculation's rounding error.


Not 11.2 G's.

3.1 G's.

It gets much lower when you don't make the unjustified assumption that the plane was descending at a constant rate, not pulling up at all, between the tower and the light pole.

Sorry, Balsamo's analysis is worthless, even accepting all of his assumptions about the flight path. His math is simply wrong. If he knew when to multiply and when to divide when calculating rates (which, I must say, is a very frightening thing not to know for a pilot or even a former pilot), and he knew how to calculate distance as a function of time for an object that's accelerating, he couldn't have come to such an absurd conclusion.

Respectfully,
Myriad

 

[Reheat]

Have "we" actually established that the plane went _over_ this antenna as opposed to around it?

Uh, no "WE" haven't.

If everyone hasn't noticed, this is similar to CIT's dogmatic assertions of "pwoof", the final word, and conclusions that can't be refuted. The attitude seems to have rubbed off and they (p4t) are getting desperate for attention.

This kind of crap makes me truly wonder if Balsamo is actually a pilot. Does he really think a pilot or (actually) anyone with knowledge of actual flying airplanes will buy this only one way approach. We don't know the exact flight path, and we don't know the precise descent angle even with these numbers. Aircraft would have easily banked to avoid the VDOT pole or it could have been approaching at a slightly different angle and the descent rate to the pole could have been VARIABLE.

There is definitely one thing Balsamo and the CIT loons are very good at and that is distortion, deception, and fraud to present their point of view (to others as dumb or dumber than they are).

 

[Myriad]

Uh, no "WE" haven't.

If everyone hasn't noticed, this is similar to CIT's dogmatic assertions of "pwoof", the final word, and conclusions that can't be refuted. The attitude seems to have rubbed off and they (p4t) are getting desperate for attention.

This kind of crap makes me truly wonder if Balsamo is actually a pilot. Does he really think a pilot or (actually) anyone with knowledge of actual flying airplanes will buy this only one way approach. We don't know the exact flight path, and we don't know the precise descent angle even with these numbers. Aircraft would have easily banked to avoid the VDOT pole or it could have been approaching at a slightly different angle and the descent rate to the pole could have been VARIABLE.

There is definitely one thing Balsamo and the CIT loons are very good at and that is distortion, deception, and fraud to present their point of view (to others as dumb or dumber than they are).

(Not to mention that he did the math wrong.)

Respectfully,
Myriad

 

[rwguinn]

Based on this topography combined with the height of the VDOT Antenna protruding into the reported flight path of American 77, it is aerodynamically and physically impossible for this aircraft to have performed the way the government would have us believe.​

Top of VDOT Height = 304 MSL (above sea level)
Top of Pole 1 height = 80 MSL

Difference = 224 feet descent required.

Distance between VDOT - Pole 1 = 2400 feet

2400/Speed 781 feet per second (according to Flight Data Recorder) = 3 seconds

224/3 seconds = 75 fps descent rate x 60 = 4480 fpm descent rate needed to reach top of pole 1 from top of VDOT Antenna.

Pole 1 distance to Pentagon = 1016 feet

1016 feet/781 fps = 1.3 seconds

4480 fpm descent needs to be arrested within 1.3 seconds.

75 * 1.3 = 97.5 foot descent within 1.3 seconds.

97.5/32 fps accel due to gravity = 3.0 G's + 1 G = 4.0 G's needed to arrest descent within 1.3 seconds and 97.5 feet vertically. However, 97.5 feet vertically is not available.

Top of pole 1 height = 80 MSL
"Impact hole" height = 33 (pentagon ground level) + 12 feet (center of pentagon hole height) = 45 MSL

80 feet (top of pole 1) - 45 (height of "impact hole") = 35 feet vertically available to arrest descent rate of 4480 fpm.

97.5/35 = 280% (G Load required to arrest 4480 fpm descent rate within 1.3 seconds and 97.5 feet vertically needs to be increased by 280%.)

280% x 4.0 G's = 11.2 G's needed to arrest descent.

Conclusion = Impossible for any transport category aircraft to descend from top of VDOT Antenna to top of pole 1 and pull level to "impact hole" as reported by the government story and seen in the DoD "5 Frames Video". 11.2 G's was never recorded in the FDR. 11.2 G's would rip the aircraft apart.

This does not account for response time to initiate the arrest. Increased time is needed or higher altitude at pentagon in order to be within aircraft structural limits, or higher peak G loads. The VDOT Antenna was present on September 11, 2001, and was not struck by any object.
Transport Category aircraft are limited to 2.5 G's positive and 1.0 negative. Although there is a margin of error built into these limits, it is not anywhere near 448% or 11.2 G's positive. Aerobatic Category Aircraft have a positive G load limit of 6.0 G's. Some may argue that the flight path "just missed" the VDOT Antenna, in which case we also worked out the numbers if the aircraft were at ground level at the antenna. The G loads required would be ~4.3 G's. Still excessive for a transport category aircraft. Not to mention the aircraft certainly was not at ground level abeam the Navy Annex and such G loads were never recorded in the Flight Data provided by the NTSB. Feel free to input the numbers yourself using above calculations as a guide and ground elevation of antenna.

(Not to mention that he did the math wrong.)

Respectfully,
Myriad

Damn that dimensional analysis stuff, anyway!

 

[Myriad]

Because of other accumulated errors, I never even got to this part:

97.5/32 fps accel due to gravity = 3.0 G's + 1 G = 4.0 G's needed to arrest descent within 1.3 seconds and 97.5 feet vertically. However, 97.5 feet vertically is not available.

... = 35 feet vertically available to arrest descent rate of 4480 fpm.

97.5/35 = 280% (G Load required to arrest 4480 fpm descent rate within 1.3 seconds and 97.5 feet vertically needs to be increased by 280%.)

280% x 4.0 G's = 11.2 G's needed to arrest descent.

Here he's used a ratio of distances (97.5/35) to scale an acceleration, when distance traveled in a given time is a quadratic function of acceleration.

In the process, he's also managed to increase earth's gravity by a factor of 280%. (Note the +1G he adds for earth's gravity to get the 4G figure, and he then multiplies that entire 4G by his distance ratio.)

Starting at the light pole descending at 75 fps, pulling up at 10.2 g, the plane would climb 178 feet in 1.3 seconds. In other words, instead of lining up with the impact hole, its projected flight path at 10.2 g vertical acceleration clears the Pentagon wall by 180 feet and takes off like a rocket.

That's at least four significant math errors. Doesn't anybody ever check the math?

ETA: Speaking of checking the math, I checked my own, and this:

Here he's used a ratio of distances (97.5/35) to scale an acceleration, when distance traveled in a given time is a quadratic function of acceleration.

is an error. Distance travelled by an accelerating object in a given time is a quadratic function, but it is a quadratic function of time, not of acceleration. Rob's method of scaling the acceleration by the ratios of the distance travelled does work, in this particular case.

So, make that only three significant math errors.

Respectfully,
Myriad

 

[Reheat]

(Not to mention that he did the math wrong.)

Respectfully,
Myriad

It's no crime to make a mistake with math, but it's the lack of JUDGMENT that's incriminating and embarrassing to him.

He has what should be considered very limited experience. He is civilian trained (which is OK), but he has flown mostly low performance stuff. He likely has never done aerobatics, nor has he ever flown an aircraft to the edge of it's performance envelope. He likely has never pulled more than 2-3 G's in his entire flying career. He can not just simply look at a proposed aeronautical situation and estimate whether it's possible or is very improbable., nor how it fits with the capability of an average pilot. He is simply a "run of the mill" low time pilot who happens to be able to call himself a "professional" in very loosely defined terms. An "expert" he ain't.

I can't always do the more complicated math, but I can usually look at a maneuver and determine it's complexity. He has consistently demonstrated an inability to do this.

He is quite simply put, a politically motivated malcontent destined to prove the generally accepted theories wrong in whatever way they deem possible. The same is true for most, if not all, of his followers.

 

[Jonnyclueless]

I'd like to see Rob's explanation of how they managed to destroy the actual flight 77 and bring in its parts and all the bodies and the passenger belongings, spread them about the scene at the exact moment of the supposed fly/over. Sure seems like it would be a lot easier to fly a plane into a building to me.

And this whole diabolical plan all hinging on a slim hope that out of thousands and thousands of witnesses no one happens to see a huge jet fly over the building and no one sees all these 100s of people needed to plant all this evidence within a few seconds (ignoring the fact that it would be impossible).

 

[Reheat]

I'd like to see Rob's explanation of how they managed to destroy the actual flight 77 and bring in its parts and all the bodies and the passenger belongings, spread them about the scene at the exact moment of the supposed fly/over. Sure seems like it would be a lot easier to fly a plane into a building to me.

And this whole diabolical plan all hinging on a slim hope that out of thousands and thousands of witnesses no one happens to see a huge jet fly over the building and no one sees all these 100s of people needed to plant all this evidence within a few seconds (ignoring the fact that it would be impossible).

Bawhahahaha!

You do it the same way they're doing it now. Just hand wave it away.

- We don't need to prove what happened to AA77 or the passengers. Surrrreee you don't.

- We know what's true and what's not true regarding the mutually exclusive contradictory testimony from witnesses 6 years after the fact. Trust us, we're professional investigators. Bwhahahahaha!

- The flyover happened in an instant and everyone was distracted by the fireball. Sure, it did. A big "honking" B-757 flies over the Pentagon in an instant? Only in Starwars!

- The evidence is planted. Sure it is by hundreds, if not, thousands of who?

On and on and on. You see, it's easy, just note the numbers of their followers. There's not many, but there are people who will believe it......

 

[Jonnyclueless]

Pay no attention to the huge glaring problems that come as the result of what we are suggesting. We aren't here to address the issues that result in our claims, just to make the claims. Move along, nothing to see here. Thank you officer Bar Bradey.

 

[R.Mackey]

So that other thread got ashcanned. Nice.

Once again, here is my post explaining that the actual minimum pullup of the aircraft is a mere 0.84 g's, which is doable by every aircraft that has ever flown. (Note: Post is in Abandon All Hope, but it is respectful and factual, and entirely consistent with the Membership Agreement.)

It should be noted that, as was pointed out to me, that post of mine should read ASL instead of AGL for all altitude measurements, so please substitute whenever you encounter AGL. This has no impact on the calculation or its conclusions.

This discussion is finished. There is no conflict. High-school level algebra is enough to demonstrate that the flight path is entirely credible.