9/11: How hard is it to hit a building at 500mph?

[TWCobra]

After a bit of thought, the issue I foresee here is that what you really need to ask pilots is whether they trust whether the agencies such as the NTSB and the FBI are telling the truth.

Pilots are generally cynical with their managements and Boards, however we tend to trust the NTSB to do an independent and thorough investigation.

I have done my own analysis of the events of 9/11 and with the exception of the 510 knot groundspeed of UA175 (which to my mind now is incorrect), I have no problem with the events as related. They gel with my experience of the aircraft and my knowledge of the security procedures in place at the time.

The reports from the passengers as to the manner in which the aircraft were flown suggests relatively inexperienced pilots who weren't concerned about flying smoothly, but knew enough to find NYC on a gin clear day and aim the aircraft with sufficient precision to hit fairly large targets.

I can't speak however for the majority of pilots as I don't know what independent thought each has put into the OS. I have put a an awful lot into it over the years.

If they haven't really thought about it as I have, then the issue is simply one of trust in the agencies. Pilots really need to spend a lot of time on forums such as this and elsewhere to get a grip on all the arguments and to make any survey valid. I for one wasn't aware of the 20% envelope extension for flutter until two days ago. Just the knowledge of that fact is intrinsic to knowing the capabilities of the aircraft. To someone like me it makes the OS much more likely.

 

[George B]

After a bit of thought, the issue I foresee here is that what you really need to ask pilots is whether they trust whether the agencies such as the NTSB and the FBI are telling the truth.

Pilots are generally cynical with their managements and Boards, however we tend to trust the NTSB to do an independent and thorough investigation.

I have done my own analysis of the events of 9/11 and with the exception of the 510 knot groundspeed of UA175 (which to my mind now is incorrect), I have no problem with the events as related. They gel with my experience of the aircraft and my knowledge of the security procedures in place at the time.

The reports from the passengers as to the manner in which the aircraft were flown suggests relatively inexperienced pilots who weren't concerned about flying smoothly, but knew enough to find NYC on a gin clear day and aim the aircraft with sufficient precision to hit fairly large targets.

I can't speak however for the majority of pilots as I don't know what independent thought each has put into the OS. I have put a an awful lot into it over the years.

If they haven't really thought about it as I have, then the issue is simply one of trust in the agencies. Pilots really need to spend a lot of time on forums such as this and elsewhere to get a grip on all the arguments and to make any survey valid. I for one wasn't aware of the 20% envelope extension for flutter until two days ago. Just the knowledge of that fact is intrinsic to knowing the capabilities of the aircraft. To someone like me it makes the OS much more likely.

It is the grey areas that make most people wonder . . . seems 911 has many of them .

 

[George B]

How about the following . . .

How is this . . . ?? OK Mick . . . is this the final ?????

Q) Could pilots with a commercial licencse have hit the the World Trade Center and the Pentagon with a 767 or 757 at the speeds observed on 9/11?(the pilots were assumed to have earned a commercial license within the previous year) (Tower #1 = 473 - 510 Knots Groundspeed, Tower#2 = 430 Knots Groundspeed, Pentagon = 460 Knots Groundspeed)


1) Yes
2) Yes, it would be fairly straightforward
3) Yes, but it would have needed a lot of concentration
4) Yes, but it would have been very difficult
5) Probably, but they were pretty lucky
6) Probably not, it would be very hard to do
7) No
8) No, the plane would be impossible to control at that speed
9) No, the plane would have fallen apart at that speed
10) No, the plane could never even reach that speed.
11) I don't know

 

[Rico]

It's probably fine I think... changing that anymore would probably be spinning your heels.

 

[xenon]

After a bit of thought, the issue I foresee here is that what you really need to ask pilots is whether they trust whether the agencies such as the NTSB and the FBI are telling the truth.

Pilots are generally cynical with their managements and Boards, however we tend to trust the NTSB to do an independent and thorough investigation.

If you haven't heard Phillip Marshall's theory yet it might be worth a few minutes to check it out.

Here's a "911 truther" who believed that all buildings were hit by planes, was a United Pilot (with all the testing that goes along), had a friend on the United plane that crashed in PA, and believed he had documents no one else had that proved his theory of how the whole thing was pulled off.

He said that there was direct Saudi involvement and 2 US Senators said the same thing. He had a book about to come out that he said would make a difference.

Marshall went on to say: “The true reason the attack was successful is because of an inside military stand-down and a coordinated training operation that prepared the hijackers to fly heavy commercial airliners. We have dozens of FBI documents to prove that this flight training was conducted California, Florida and Arizona in the 18 months leading up to the attack.”
​

He's dead now, accused of shooting his teenaged kids and his dog before he turned the gun on himself. And he can't defend himself.

The least I can do is ask as many people as I can to read what he had to say. He's not stupid or boring.

Metabunk Phillip Marshall thread
www.santabarbaraview.com/phillip-marshall-wrote-about-a-conspiracy

http://thebigbamboozle.tumblr.com/


@1:44:28 "...you really don't have any security when you have so many people that have access to your personal whereabouts..."
and @2:15:42
"...and then we have to push together and I'm going to dedicate-you know- maybe the next 5 years, 10 years, whatever..."
www.youtube.com/watch?v=oUvEECOl6Zs

 

[George B]

OK . . . Mick . . . How about a shake down cruise of the Poll on MetaBunk . . . could you set it up???

Q) Could pilots with a commercial licencse have hit the the World Trade Center and the Pentagon with a 767 or 757 at the speeds observed on 9/11? (the pilots were assumed to have earned a commercial license within the previous year) (Tower #1 = 473 - 510 Knots Groundspeed, Tower#2 = 430 Knots Groundspeed, Pentagon = 460 Knots Groundspeed)

1) Yes
2) Yes, it would be fairly straightforward
3) Yes, but it would have needed a lot of concentration
4) Yes, but it would have been very difficult
5) Probably, but they were pretty lucky
6) Probably not, it would be very hard to do
7) No
8) No, the plane would be impossible to control at that speed
9) No, the plane would have fallen apart at that speed
10) No, the plane could never even reach that speed.
11) I don't know

Flight 77. . . Pentagon source

http://en.wikipedia.org/wiki/America...ines_Flight_77

NTSB sources
http://pilotsfor911truth.org/p4t/Rad...A11,_UA175.pdf

http://www.documentingreality.com/fo...tudy-ua175.pdf

Flight experience source

http://www.911myths.com/index.php/Fl...chool_Dropouts

 

[Mick West]

OK . . . Mick . . . How about a shake down cruise of the Poll on MetaBunk . . . could you set it up???



Flight 77. . . Pentagon source

http://en.wikipedia.org/wiki/America...ines_Flight_77

NTSB sources
http://pilotsfor911truth.org/p4t/Rad...A11,_UA175.pdf

http://www.documentingreality.com/fo...tudy-ua175.pdf

Flight experience source

http://www.911myths.com/index.php/Fl...chool_Dropouts

It's not going to tell you anything, a very large portion of the visitors here are believers in bunk.

 

[George B]

How is this . . . ?? OK Mick . . . is this the final ?????

It's not going to tell you anything, a very large portion of the visitors here are believers in bunk.

I am not looking for the results as much as I am looking for the impressions and feedback of the participants . . . does it fit the situation? Are there better options ? Do people need additional information, etc??? When we go to other Forums I want it to be as fool proof as possible . . .

 

[George B]

It's not going to tell you anything, a very large portion of the visitors here are believers in bunk.

I am not looking at the results as much as I am looking for impressions and feedback. . . . do the options work with the question? Do people need more information? I want this poll as good as it can be because we may only have one or two chances to see it through. . . . Humor me. . . .

The objective was to see what professional pilots thought about the questions in general . . . this is a test. . . .alpha testing

 

[George B]

Shake down cruise . . .

Could pilots with a commercial licencse have hit the the World Trade Center and the Pentagon with a 767 or 757 at the speeds observed on 9/11?
POLL: Could pilots with a commercial licencse have hit the the World Trade Center and the Pentagon with a 767 or 757 at the sp

7) No 25.5% (27)
2) Yes, it would be fairly straightforward 15.1% (16)
6) Probably not, it would be very hard to do 14.2% (15)
8) No, the plane would be impossible to control at that speed 12.3% (13)
1) Yes 10.4% (11)
9) No, the plane would have fallen apart at that speed 7.5% (8)
10) No, the plane could never even reach that speed. 4.7% (5)
11) I don't know 4.7% (5)
4) Yes, but it would have been very difficult 3.8% (4)
3) Yes, but it would have needed a lot of concentration 0.9% (1)
5) Probably, but they were pretty lucky 0.9% (1)
Blank (View Results) (21)


Non-Blank Votes: 106


Q) Could pilots with a commercial licencse have hit the the World Trade Center and the Pentagon with a 767 or 757 at the speeds observed on 9/11? (the pilots were assumed to have earned a commercial license within the previous year) (Tower #1 = 473 - 510 Knots Groundspeed, Tower#2 = 430 Knots Groundspeed, Pentagon = 460 Knots Groundspeed)


1) Yes
2) Yes, it would be fairly straightforward
3) Yes, but it would have needed a lot of concentration
4) Yes, but it would have been very difficult
5) Probably, but they were pretty lucky
6) Probably not, it would be very hard to do
7) No
8) No, the plane would be impossible to control at that speed
9) No, the plane would have fallen apart at that speed
10) No, the plane could never even reach that speed.
11) I don't know
Flight 77. . . Pentagon source


[link to


NTSB sources


[link to


[link to pilotsfor911truth.org]


Flight experience source


[link to


Last Edited by George B on 02/16/2013 08:39 AM
Martin Luther King . . . Our lives begin to end the day we become silent about things that matter!


All truths are easy to understand once they are discovered; the point is to discover them.
Galileo Galilei, Italian astronomer & physicist (1564 - 1642)


The only thing guaranteed in life is deception. . . everything else is optional . . . George B

Content from External Source

 

[Rico]

Poll results from your post on godlikeproductions ?

It's actually interesting to see the split there.

I know a guy there said you should keep it a simple yes/no/don't know poll, but in looking at this, I think getting rid of the generic yes/no seems better IMO.

 

[George B]

Poll results from your post on godlikeproductions ?

It's actually interesting to see the split there.

I know a guy there said you should keep it a simple yes/no/don't know poll, but in looking at this, I think getting rid of the generic yes/no seems better IMO.

Anyone else with a comment? I think you could go either way . . . sometimes simpler is better . . .

 

[Mick West]

Anyone else with a comment? I think you could go either way . . . sometimes simpler is better . . .

I'd move the plain "yes" and "no" answers to the end of their sections, and change them to "yes (other)", or "no (other)", which should encourage people to actually pick a reason for their yes/no choice.

 

[George B]

I'd move the plain "yes" and "no" answers to the end of their sections, and change them to "yes (other)", or "no (other)", which should encourage people to actually pick a reason for their yes/no choice.

Like this . . .

1) Yes, it would be fairly straightforward
2) Yes, but it would have needed a lot of concentration
3) Yes, but it would have been very difficult
4) Yes (other)
5) Probably, but they were pretty lucky
6) Probably not, it would be very hard to do
7) No, the plane would be impossible to control at that speed
8) No, the plane would have fallen apart at that speed
9) No, the plane could never even reach that speed.
10) No (other)
11) I don't know

 

[Mick West]

Yes.

 

[George B]

Yes.

So what 's next?

 

[George B]

Interesting simulator demo seems to indicate air speed makes aircraft uncontrollable near sea level . . . see 7:15 minute mark . . .

FLIGHT 175 SPEED CHALLENGE
M.I.T. 503 mph - 437 knots?
F.A.A. 586 mph - 509 knots?
N.I.S.T 546 mph - 474 knots?
F.E.M.A 590 mph - 512 knots??!!
MY TEST - above 360 mph - 320 knots level flight is impossible. The ' hijackers ' did not possess the knowledge and training to be able to accurately 'trim' a 767.
They spent a total of 6 hours in an old style 727 cockpit simulator and were given temporary 6 month licenses to fly small 2 engined aircraft.

Content from External Source

http://m.youtube.com/#/watch?v=1-9EMrna-WU&desktop_uri=/watch?v=1-9EMrna-WU


http://www.youtube.com/watch?v=1-9EMrna-WU
​

 

[Rico]

Interesting.

I have that exact model on my desktop sim, so I'll have to try this out some time. The last statement of the hijackers not possessing knowledge and training about trimming, in my opinion, is likely bogus. The usage and importance of trim is instilled on the pilot pretty much the day they learn to fly. Improper trim makes any aircraft difficult to fly regardless. I think the hijackers knew about this. If it's true that they spent 6 hours on a 727 simulator, then they should definitely have known. The electric switch for the trim is pretty much in exactly the same spot in the 727 as it is in the 767, which is the top of the control column (the wheel) where you place your hand.

 

[Billzilla]

The last statement of the hijackers not possessing knowledge and training about trimming, in my opinion, is likely bogus. The usage and importance of trim is instilled on the pilot pretty much the day they learn to fly.

I'm reluctant to dip back into this thread, it makes my head hurt, but ...
I used to be a flying instructor. Trimming is in lesson #1 and it's done many times every flight after that. Every single pilot (except Airbus drivers) trim with every change of power and/or airspeed, it's as simple as that.

 

[Rico]

Simulators generally don't simulate some things, and you are right about this earlier, George.

But heh, using a similar, if not higher fidelity simulator model than the one seen in that youtube video posted, I quite frankly had no problem controlling the airplane flying it towards the Eiffel Tower under the assumption that the wings don't tear off. That little flight simulator demo used a PMDG 747 model. I used a newer PMDG 737NG model. The maker of the video doesn't know what he is talking about. Disclaimer: No towers were hurt in the process, and I am not a terrorist.

552 kts groundspeed

 

[Mick West]

Yeah trimming is fundamental. If you don't trim, then the controls feel like they are working against you, so you trim until they feel right. Frequently, on every flight.

 

[Mick West]

So what 's next?

Next find a pilot forum willing to take the survey.

 

[TWCobra]

Flying on Flight simulator is fun but.....

I took the FSX 737 to 550 knots in level flight at 1000 feet and it was smooth as silk. Does that prove the OS?

FSX is a 35 dollar flight sim and for that money you get a 35 dollar representation of the atmosphere and aircraft structural integrity.
I was in a real flight sim today... Shame we didn't have time to try a few things.

 

[George B]

Next find a pilot forum willing to take the survey.

I think we need some assistance from real pilots on this task . . . I don't talk the lingo and would be most suspect by the site managers. . . . I don't mind doing the grunt work but I need a proper introduction, etc. . . .

 

[George B]

Simulators generally don't simulate some things, and you are right about this earlier, George.

But heh, using a similar, if not higher fidelity simulator model than the one seen in that youtube video posted, I quite frankly had no problem controlling the airplane flying it towards the Eiffel Tower under the assumption that the wings don't tear off. That little flight simulator demo used a PMDG 747 model. I used a newer PMDG 737NG model. The maker of the video doesn't know what he is talking about. Disclaimer: No towers were hurt in the process, and I am not a terrorist.

552 kts groundspeed

So you get what you pay for. . . .what a novel idea . . .

 

[George B]

Question . . . How was ground effect overcome by the pilot and aircraft at the Pentagon?



http://www.youtube.com/watch?v=v5jU1mADgRo


As the 757 approached the Pentagon, the aircraft was flying low enough to take down light poles at 500+ MPH.


If ground effect exponentially increases lift on the aircraft's wings . . . ?

​

Flight 77, flying at 530 mph (853 km/h, 237 m/s, or 460 knots) over the Navy Annex Building adjacent to Arlington National Cemetery,[36]​ crashed into the western side of the Pentagon
http://en.m.wikipedia.org/wiki/American_Airlines_Flight_77#section_2

Content from External Source

 

[Rico]

Ground effect doesn't 'exponentially' increase lift. It's more of a cushion effect due to the interruption of downwash and also that of wing-tip vortices (induced drag). To compensate, they simply had to push the plane down more slightly, thereby decreasing the lift component of the wing.

 

[Rico]

Flying on Flight simulator is fun but.....

I took the FSX 737 to 550 knots in level flight at 1000 feet and it was smooth as silk. Does that prove the OS?

FSX is a 35 dollar flight sim and for that money you get a 35 dollar representation of the atmosphere and aircraft structural integrity.
I was in a real flight sim today... Shame we didn't have time to try a few things.

True, though you have to admit that the merit of flight sim being a little bit more than a "35 dollar" representation. The local flight schools here use red bird motion simulators that use pretty much exactly the same software as the desktop simulator, with all the same loading screens. There are a few things that it can do:
-Basic attitudes and movements
-Advanced system simulations if modelled
-Accurate navigation and fairly accurate instrument flying
-Some degree of aerodynamic accuracy, though this is the area that also lacks the most

"Real" flight sims like the one you use at the airlines are undoubtedly more accurate representations of a particular aircraft you are flying, but it likely has it's own share of drawbacks in the same areas, no?

 

[George B]

Interesting comment about G-forces . . .

I am ex-Air Force and a pilot with tons of hours in several types as well as professional 767 simulator time.

No matter how many times a hijacker practiced such a maneuver on a PC simulator, the G-forces of the last turn exhibited by the second tower aircraft would have made it next to impossible for a human.


That is a 500 knot, 90 degree bank at sea level, meaning the pilot was pulling the maximum possible Gs - which a 767 cockpit is not equipped to handle.


By this, I mean that the pilot would have been unable to move the controls when subjected to 7+ G because the seat is upright and the pilots arms must extend straight out to reach the yoke.


His arms would have fallen off the yoke, so it is a self-limiting exercise.


This is assuming that the 767 does not have a limiter and stick shaker set to prevent such violent maneuvers. I'd have to check the POH or even call some guys at Boeing I used to know.
http://www.godlikeproductions.com/forum1/message2141354/pg4#lastpost

 

[George B]

Ground effect doesn't 'exponentially' increase lift. It's more of a cushion effect due to the interruption of downwash and also that of wing-tip vortices (induced drag). To compensate, they simply had to push the plane down more slightly, thereby decreasing the lift component of the wing.

So you see no problem with a 757 hitting the Pentagon parallel to the ground well below the height of the wing length at over 500 mph ???

 

[Cairenn]

Why didn't you post the REST of that posters post?

"the smoking gun is the perfect, vertical demolition of the towers AND BUILDING FUCKING SEVEN (!!!!).

The smoking gun of this farce doesn't have to be the aircraft.

You find one smoking gun and you have a farce.

Period.

Anyway, my point is that those plane were flown by computer - and NOT the standard autopilot. All that can do is hold altitude, speed and heading.

Of course, maybe those planes didn't even exists. Hmmm? Ever see a modern action movie?"

Content from External Source

Maybe because it would cause doubt on the his other statement?

 

[George B]

Why didn't you post the REST of that posters post?

"the smoking gun is the perfect, vertical demolition of the towers AND BUILDING FUCKING SEVEN (!!!!).

The smoking gun of this farce doesn't have to be the aircraft.

You find one smoking gun and you have a farce.

Period.

Anyway, my point is that those plane were flown by computer - and NOT the standard autopilot. All that can do is hold altitude, speed and heading.

Of course, maybe those planes didn't even exists. Hmmm? Ever see a modern action movie?"

Content from External Source

Maybe because it would cause doubt on the his other statement?

If I was worried about that I wouldn't have posted the hot link . . .

 

[Rico]

Interesting comment about G-forces . . .

Completely bunk statement, using background and authority to instill credibility.

United 175 was never in a 90 degree bank--there is no evidence, nor reason to suspect that the aircraft was ever at 90 degrees. First time I've heard of that one. They were in a steep descending turn, and they hit the building at 38 degrees angle of bank. Unless they did an abrupt pull-up, they shouldn't have experienced more than 2 or 3 G's.

Also, there are no stick shaker or what-not to prevent such maneuvers. The stick shaker is there as a stall warning device. They might have had a bank angle alarm for going past 30 degrees, but that's about it.

 

[MikeC]

So you see no problem with a 757 hitting the Pentagon parallel to the ground well below the height of the wing length at over 500 mph ???

Nope.

Ground effect increases lift - but you can counter that with an attitude change - go a little more nose down.

It's not a problem at all as far as I can tell.....except for people who want it to be.

 

[George B]

So between the 510 knots at Tower two and possible breakup of the airframe was only 55 knots . . . see below . . .

At low altitudes, drag and thermal effects are much more severe than they are at high altitudes, because of the higher air density at low altitudes. An airliner flying at 650 miles per hour (565 knots, added not by author) at sea level, or a fighter flying at MACH 2.5 at sea level, would probably be torn apart by the denser air. (In fact, at least two 737 accidents involved “frozen” rudder mechanisms which caused the jets to go into full-speed powered nosedives, and both 737s came apart before hitting the ground). So drag is much higher at lower altitudes, making it harder – and more dangerous – to fly at top speed through the denser air.
Not only that, but engines having all that dense air shoved into them (if they were flown very fast at low altitudes) would get dangerously hot. Remember how, when we talked about ramjets, we said that the turbine inlet temperature was just about the most important restriction that limits the thrust an engine can put out. The air at lower altitudes is hotter and at higher pressure than high-altitude air. If you compress that low-altitude air, it becomes even hotter. Engines have a much easier time working with high-altitude air: When the engine takes in air that is colder and less dense to begin with, it can be compressed more before reaching those limiting temperatures. This means that the colder and less-dense air at higher altitudes allows a jet engine to run at higher RPMs and at higher compression rations, which make it more efficient. It also means that the engine intake can swallow more of that air per second and compress it properly, and thus burn more fuel and generate more thrust.


http://www.airplanedesign.info/20.htm

Content from External Source

 

[MikeC]

none of this is relevant - it woudl nmatter if hte airliner and egines weer expected to be in seerrvicce for another 10-15-20 years when these stressesmight result in weakened airframes or engine componsnts leading to failure some time "down the track".

but none of that is important in the time scale of the attack.


as far as I am aware only one of the boeing 737 "rudder actuator" crash aircraft broke up before impact - the Copa Airlines flight 201 in 1992, which dove pretty much vertically from
cruise altitude to 10-13,000 feet and then broke up. And this one is thought to not involve the rudder at all - but rather erronious flight instrument readings leading to the pilots becoming disoriented.

For the othe "Rudder failure" accidents - you can see the NTSB report for United Airline 585 here (nearly 4 mb pdf):

About 20 seconds prior to the crash, the rate of heading change increased,
consistent with a 20-degree bank angle and a turn for alignment with the runway. Sixteen
seconds prior to the crash, the thrust was increased to about 6,000 pounds per engine. As
the thrust was increasing, the first officer made the “1,000 feet” call. Within the next
4 seconds, and about 9 seconds prior to the crash, the heading rate increased to about
5-degrees per second to the right, nearly twice that of a standard rate turn. The first officer
said “Oh God,” followed by the captain, in the last 8 seconds, calling for 15 degrees of
flaps. This selection of 15-degrees flaps, in combination with increased thrust, is
consistent with the initiation of a go-around. The altitude decreased rapidly, the indicated
airspeed increased to over 200 knots, and the normal acceleration increased to over 4 G.
The airplane impacted relatively flat terrain 3.47 nautical miles south of the south
end of runway 35 and .17 nautical miles to the east of the extended centerline of runway
35 at the Colorado Springs Municipal Airport. All of the occupants on board the flight
received fatal injuries. The airplane was destroyed by impact forces and postcrash fire.

Content from External Source

- no mention of pre-impact breakup.

and US Air 427 in 1994 NTSB summary:

According to the ATC transcript, a radio transmission from USAir flight 427 about
1903:10 stated, “Oh (unintelligible) Oh [expletive].”20 The approach controller reported
that, at that time, flight 427’s altitude readout on the radar screen indicated 5,300 feet.
About 1903:14, the controller stated “USAir 427 maintain 6,000, over.” About 1903:15,
the CVR transcript indicated that the captain made a radio transmission, stating “four
twenty seven emergency.” Between 1903:18.1 and 1903:19.7, the CVR recorded the
captain stating “pull…pull…pull.” From about 1903:09 to about 1903:22, the first
officer’s radio microphone was activated and deactivated repeatedly, so the ATC tapes
recorded exclamations and other sounds from the accident airplane. During postaccident
interviews, air traffic controllers who were in the tower cab when the accident occurred
reported that they observed dense smoke rising to the northwest of the airport shortly after
USAir flight 427’s final transmission. The CVR stopped recording at 1903:22.8.
About 1903:23, the airplane impacted hilly, wooded terrain near Aliquippa,
Pennsylvania, approximately 6 miles northwest of PIT. The location of the accident was
40° 36 minutes, 14.14 seconds north latitude, 80° 18 minutes, 36.95 seconds west
longitude at an elevation of about 930 feet msl. The accident occurred during daylight
hours.

Content from External Source

Again no breakup.

given the obvious inaccuracy in the assertions in that excerpt I would ask for actual evidence to support the remaining comments rathe than accepting them at face value.

 

[Rico]

So you see no problem with a 757 hitting the Pentagon parallel to the ground well below the height of the wing length at over 500 mph ???

If we go by the NTSB's Flight Data Recorder data, Flight 77 wasn't "parallel to the ground." It was diving to the ground at an angle and kind shallowed out last minute. The ground effect of the 757 would be about it's wingspan, which is about 124 feet.

http://www.youtube.com/watch?v=aP3EMnCx4yI

Also to note, it was at about 300 knots before it started the dive, which it then accelerated to 460 knots (~520 mph) in the dive. It's likely how the other two aircraft hit the WTC too. Start out slow and accelerate.

Outside of overspeeding, structural integrity, and potentially hitting objects on the ground, the answer is no. What kind of problems do you see?

 

[George B]

none of this is relevant - it woudl nmatter if hte airliner and egines weer expected to be in seerrvicce for another 10-15-20 years when these stressesmight result in weakened airframes or engine componsnts leading to failure some time "down the track".

but none of that is important in the time scale of the attack.


as far as I am aware only one of the boeing 737 "rudder actuator" crash aircraft broke up before impact - the Copa Airlines flight 201 in 1992, which dove pretty much vertically from
cruise altitude to 10-13,000 feet and then broke up. And this one is thought to not involve the rudder at all - but rather erronious flight instrument readings leading to the pilots becoming disoriented.

For the othe "Rudder failure" accidents - you can see the NTSB report for United Airline 585 here (nearly 4 mb pdf):

About 20 seconds prior to the crash, the rate of heading change increased,
consistent with a 20-degree bank angle and a turn for alignment with the runway. Sixteen
seconds prior to the crash, the thrust was increased to about 6,000 pounds per engine. As
the thrust was increasing, the first officer made the “1,000 feet” call. Within the next
4 seconds, and about 9 seconds prior to the crash, the heading rate increased to about
5-degrees per second to the right, nearly twice that of a standard rate turn. The first officer
said “Oh God,” followed by the captain, in the last 8 seconds, calling for 15 degrees of
flaps. This selection of 15-degrees flaps, in combination with increased thrust, is
consistent with the initiation of a go-around. The altitude decreased rapidly, the indicated
airspeed increased to over 200 knots, and the normal acceleration increased to over 4 G.
The airplane impacted relatively flat terrain 3.47 nautical miles south of the south
end of runway 35 and .17 nautical miles to the east of the extended centerline of runway
35 at the Colorado Springs Municipal Airport. All of the occupants on board the flight
received fatal injuries. The airplane was destroyed by impact forces and postcrash fire.

Content from External Source

- no mention of pre-impact breakup.

and US Air 427 in 1994 NTSB summary:

According to the ATC transcript, a radio transmission from USAir flight 427 about
1903:10 stated, “Oh (unintelligible) Oh [expletive].”20 The approach controller reported
that, at that time, flight 427’s altitude readout on the radar screen indicated 5,300 feet.
About 1903:14, the controller stated “USAir 427 maintain 6,000, over.” About 1903:15,
the CVR transcript indicated that the captain made a radio transmission, stating “four
twenty seven emergency.” Between 1903:18.1 and 1903:19.7, the CVR recorded the
captain stating “pull…pull…pull.” From about 1903:09 to about 1903:22, the first
officer’s radio microphone was activated and deactivated repeatedly, so the ATC tapes
recorded exclamations and other sounds from the accident airplane. During postaccident
interviews, air traffic controllers who were in the tower cab when the accident occurred
reported that they observed dense smoke rising to the northwest of the airport shortly after
USAir flight 427’s final transmission. The CVR stopped recording at 1903:22.8.
About 1903:23, the airplane impacted hilly, wooded terrain near Aliquippa,
Pennsylvania, approximately 6 miles northwest of PIT. The location of the accident was
40° 36 minutes, 14.14 seconds north latitude, 80° 18 minutes, 36.95 seconds west
longitude at an elevation of about 930 feet msl. The accident occurred during daylight
hours.

Content from External Source

Again no breakup.

given the obvious inaccuracy in the assertions in that excerpt I would ask for actual evidence to support the remaining comments rathe than accepting them at face value.

OK . . . so how does one find the breakup speed of a 767 or 757...

Operating Performance: 200/300/200ER & 300ER
• Vno/Mno 360/0.80 Normal Operating Speed
• Vne/Mne 516/0.86 Mach Never Exceed Speed
• Vat 140-145 knots Landing @ Runway Threshold Speed @ MLW full flap/Gear down
• Vat with X-Plane is @ 50'.... 25'....10'
• Max Cruise 488 - 492 kts , Long Range Cruise 457 - 461 kts
• Max Alt. 43,000' , Long Range Alt 33,000' - 39,000'
* DO NOT Exceed 250kts @ or Below 10,000ft Altitude.*


http://knology.net/~stirmac/POHfiles/767 POH.pdf


Cruise Speeds:
• Max Cruise Speed is 490kts @ 35,000'
• Long Range Cruise is 460 - 465kts @ 35,000 - 39,000'
• Cruise Speed 485 - 490 kts Cruise Altitude 30,000 - 39,000ft depending on weight.
• Typical Cruise Speed is 0.78 - 0.82 Mach @ FL300 - FL390 (30,000-39,000ft)




MLW = Maximum Landing Weight
MTO = Maximum Take-off Weight
V2 = Safe Climb-out speed (The speed after Vr, Rotation speed or Lift-off speed) Vat = Landing speed at runway threshold Flap/Gear down (X-Plane @ 50'...25'...10') Vapr= Approach Speed , just add 5-10kts to Vat with flap/gear down @ MLW or less Vno = Normal Operating Speed
Vmo = Maximum Operating Speed
Vne = Never Exceed Speed
FL350 = Flight Level 35,000

Content from External Source

 

[George B]

If we go by the NTSB's Flight Data Recorder data, Flight 77 wasn't "parallel to the ground." It was diving to the ground at an angle and kind shallowed out last minute. The ground effect of the 757 would be about it's wingspan, which is about 124 feet.

http://www.youtube.com/watch?v=aP3EMnCx4yI

Outside of overspeeding, structural integrity, and potentially hitting objects on the ground, the answer is no. What kind of problems do you see?

Well during the last moments . . . would there not have been an altitude change cause by ground effect . . . a last moment rise in the trajectory . . . I am sure the pilot couldn't have reacted quick enough??

 

[MikeC]

You are assuming again - if ground effect had any influence on his dive that may well have been to make the dive shallower and give precisely the result that happened rather than hitting the ground earlier!

Stop inventing things.