9/11 conspiracy debate

[Maki]

Um, As the design envelope for a 767 - 200 series is Vne 516 knots IAS, then 510 kts is within the envelope, not above it.

Also remember that the 510 Kts is estimated ground speed not IAS which is unknown.

Is 510 knots at 700 feet above the ground within the 767 envelope? Are you aware of the fact that things change with altitude? The atmosphere is about 3 times more dense near sea level than it is at cruising altitude for those planes. That affects engine performance and the forces acting on the aircraft.

What does the indicated speed have to do with the physics involved with this?

Why am I even explaining this? Just ask your airline pilot friends what would happen if they flew a 767 at 500 knots at 700 feet above sea level and if novices could execute complicated manouvers under those conditions.

Believe what you want, but there is no need to distort facts such as the design envelope of an aircraft at a given altitude.

[onearmedbandit]

The airplane was UA175, a Boeing 767-200, shortly before crashing into World Trade Center Tower 2. Based on analysis of radar data, the National Transportation and Safety Board reported the groundspeed just before impact as 510 knots. This is well beyond the maximum operating velocity of 360 knots, and maximum dive velocity of 410 knots. The possibilities as I see them are: (1) this wasn't a standard 767-200; (2) the radar data was compromised in some manner; (3) the NTSB analysis was erroneous; or (4) the 767 flew well beyond its flight envelope, was controllable, and managed to hit a relatively small target. Which organization has the greater responsibility for acknowledging the elephant in the room? The NTSB, NASA, Boeing, or the AIAA? Have engineers authored papers, but the AIAA or NASA won't publish them? Or, does the ethical responsibility lie not with organizations, but with individual aeronautical engineers? Have engineers just looked the other way?"

Your argument is seriously flawed when the basic facts are incorrect, and you can't go changing your argument by now talking about flying at 700ft. Your source above claims the maximum operating velocity of the 767-200 is 360kts, 410 in a dive. This is clearly wrong as stated here.

Performance
767-200 - Max cruising speed 914km/h (493kt), economical cruising speed 854km/h (461kt).

[Jantar]

Is 510 knots at 700 feet above the ground within the 767 envelope? Are you aware of the fact that things change with altitude? The atmosphere is about 3 times more dense near sea level than it is at cruising altitude for those planes. That affects engine performance and the forces acting on the aircraft.

What does the indicated speed have to do with the physics involved with this?

Why am I even explaining this? Just ask your airline pilot friends what would happen if they flew a 767 at 500 knots at 700 feet above sea level and if novices could execute complicated manouvers under those conditions.

Believe what you want, but there is no need to distort facts such as the design envelope of an aircraft at a given altitude.

Exactly! the IAS changes with altitude and air density. The IAS and true airspeed are only identical at sea level. At higher altitudes the true airspeed is higher than IAS. There is another critical airspeed that I believe you may be getting confused with and that is the Manouvering speed Va. This is the maximum speed at which it is safe to apply full control deflection. I have been unble to find out just what this is for a 767-200, but a rule of thumb is 2/3 Vne. So that would make it around 370 Kts, very close to your claimed 360 kts.

One other thing I'm intersted in: Just what complicated manouvers are these aircraft supposed to have executed? From the video I've seen there was never any more than a rather gentle bank.

[Maki]

Ok, educate yourself about flying large airliners at 500 knots near the ground and the problems involved with manouvering and hitting small targets at such speeds. Enjoy...
If you still believe people who never flew a large airliner at all did that, fine. In my experience people believe what they want to believe.

You are the person bringing up these different measures of air speed so the only source of confusion is you. I am simply talking about the actual air speed. You obviously have little understanding of the physics involved and the effects of air density at different atitudes.

[Maki]

Your argument is seriously flawed when the basic facts are incorrect, and you can't go changing your argument by now talking about flying at 700ft. Your source above claims the maximum operating velocity of the 767-200 is 360kts, 410 in a dive. This is clearly wrong as stated here.

I am not changing anything. Where does your link talk about a dive? I am discussing the performance of these aircraft at near sea level and so is my source. Yours is not. Do you think the WTC was 30.000 feet high maybe?

[onearmedbandit]

I am not changing anything. Where does your link talk about a dive? I am discussing the performance of these aircraft at near sea level and so is my source. Yours is not. Do you think the WTC was 30.000 feet high maybe?

This might answer a few of your concerns.



Let’s now get to the question of Lear’s statement regarding the “impossible speed” at which both AA11 and UA175 were flying, according to official reports. Here are the simple facts relating to the Boeing 767-200’s AA11 & UA175 on 9/11;

1. The speed of the aircraft that hit the WTC was officially reported as between 500mph and 560mph ground speed, calculated by the observed point to point distance covered over time.
2. A Boeing 767-200 airframe is rated to .86 of Mach speed (speed of sound) at any altitude before the risk of structural failure. It as the aircraft approaches the speed of sound when the properties extreme high and low pressure areas can have destructive effects on the airframe. This figure is as with all limits set conservatively.
3. The speed of sound at approximate sea level is 761 mph on a standard day. Therefore the theoretical maximum speed the 767-200 can reach intact is, conservatively, .86 x 761mph = 654mph or approximately 100mph above the officially reported speed of AA11 or UA175.
4. The 767-200 is an aircraft that’s considered highly powered due to its requirement to function with only one engine for ETOPS - Extended-range Twin-engine Operational Performance Standards. It is capable of taking off fully loaded with only one engine.
5. Lear’s argument: The normal maximum operating speed at sea level is 360Knots/h (Nautical miles) which equates to 415mph (a lot less than seen on 9/11). It is not, as Lear stated in his interview 360mph, which is considerably less. This maximum operating speed (Indicated) used is something that is decided by Boeing in conjunction with the operator and is not a structural or performance limit; rather it has been determined to be a safe speed at which to operate with commercial passengers on board and to prevent the need for increased maintenance.
6. The 767-200 is considered by pilots and aviation professionals to be a “slick” or “low drag” aircraft, being without bulbous construction and with highly swept 31.5 degree wings. It is well known that it is difficult to keep the 767 aircraft from over-speeding during decent; due to its low drag/high power configuration.

Considering all of these facts we are still left with the question: Can a 767-200 make 560mph ground speed at sea level or the equivalent of .74 of Mach speed? We know that it is definitely within its design parameters and that it can do so at high altitude (not in question), but can it do this at sea level (higher air density)? Considering that 560mph is 145mph faster than its recommended maximum operating speed (Lear’s argument), it is simply not possible to test this speed in a commercial 767-200 aircraft; it would be against the aircraft manufacturer’s recommendations, outside of standard company operating procedures and against the authorities’ rules (FAA in US). For these reasons we will not see a 767-200 attain 560mph in operation unless it is in the middle of an aircraft incident or accident. The only way to test this is in an accredited Full Flight Simulator.

Boeing 767-300 Simulator Experiment on the 29th of April 2009

The idea of using a Full Flight Simulator accredited by the FAA or relevant authority to test the maximum attainable speed for a Boeing 767-200 is only possible if you have the thousands of dollars it costs to hire such or access to one through your vocation. Well it just so happens that during my training in Sydney I worked in our Simulator Centre as a technician where Australian 767 pilots are trained and certified. The simulators are extremely busy and it is difficult to get access during the day or evening. On the 29th of April, after I had completed my work for the night shift, I drove to the Simulator Facilities at our Flight Training Centre at the Jet Base. I rang the nightshift maintenance staff and gained access to the building at just after 3am on the 29th of April 2009. Being licensed on the 767 and familiar with the facilities, I asked if I might access the simulator under the supervision of the technician on duty, Daniel Gazdoc. He agreed to help and I explained what I wanted to do and why.

We boarded the simulator (#2) which was configured as a GE powered 767-300 (marginally different from the 767-200, being a little longer and a bit heavier) and booted up the computers, placing the aircraft at 2000ft above Sydney (This altitude was set to prevent us hitting any obstacles if I lost control, resulting in an insignificant 6mph difference compared to AA11 and UA175; that is compared to Mach speed). We set the aircraft weight to 130,000kgs (286,000 pounds), approximately what it would have been on Flight 11 and 175; that is, lightly loaded. We pulled the aural warning circuit breakers on the overhead panel so that we would not be annoyed by configuration and over-speed warnings during our test. I sat in the pilot’s seat and pushed the throttles to the stops, maintaining wings level and a flat trajectory. To my surprise, within a few seconds we had exceeded the maximum operating Indicated Air Speed of 360Knots/h (415mph); then the needle continued to rise until it hit the stop on the indicator at over 400Knots/h (460mph). At this very fast speed you only have the Mach indication to go off, as IAS (Indicated Air Speed) is off the scale. The aircraft continued to increase speed until it reached .86 Mach (654mph), which is its rated airframe Mach speed limit. This makes complete sense, as the manufacturer does not want you to exceed this but wants you to have the maximum thrust available in case of emergency. At this air speed I was surprised at how easy it was to maintain my attitude once the aircraft was trimmed.

Originally thinking I was going to have to do a dive to attain the speeds of AA11 and UA175 due to the engines possibly struggling to make enough thrust, I thought it would be good to see what speed we could achieve in a shallow dive. We took the aircraft to 10,000ft and I commenced a 5 degree dive to 2,000ft and found that the aircraft attained and maintained a speed of .89 Mach (approaching 700mph) and was reasonably easy to control for a non-pilot. We did these tests a couple more times to be sure and then at about 3:45am I left the simulator. Daniel was happy for me to record his name.

How accurate are Full Flight Simulators and how does the 767-300 compare to the 200?

The flight simulator in which I carried out this test is considered to be an exact representation of the real aircraft. It takes into account all of the test data gathered during the initial flight testing of the 767-200/300 and ongoing data gathered from Flight Data Recorders and observed performance. The instrumentation is exactly the same as the actual aircraft and can be put into service in a real aircraft. The performance of the aircraft engines and the aircraft’s structure are modelled so that a pilot can remain current without doing as many actual flight hours. Basically it is fair to say that what you can do in the simulator can be done in real life, especially as relates to thrust, lift and drag.

After doing this test I then spent a few days on the flight line checking whether the average 767 pilot thought that the engines could achieve .86 Mach at sea level considering what I found in the sim. Mostly they agreed--due to the exceptional power to weight ratio of the 767 series, and its low drag airframe, it was probable it could do just that. I also asked the older pilots that flew in the Pratt and Whitney (JT9-7R4) powered 767-200 series aircraft if those aircraft were similar to fly to the 767-300 General Electric (CF6) powered aircraft they now fly (current simulator configuration). They said they were very similar, having a little less power but being a little shorter and lighter, thus giving them nearly exactly the same power to weight ratio. Once again this was no surprise to me as this is what the manufacturer does--matches the airframe to the power plant to meet the performance specifications which are basically the same for 200 and the 300 series Boeing 767.

[Maki]

Well done, there is some sanity. It seems to be possible but it is far outside the design envelope. That is why the flying supposedly done by complete novices on 911 stretches the imagination.

[ducatilover]

Well done, there is some sanity. It seems to be possible but it is far outside the design envelope. That is why the flying done by complete novices on 911 stretches the imagination.

He said he had no real problems at far higher speeds in the sim, he isn't a practising pilot either by the sounds of it.

[BoristheBiter]

Well done, there is some sanity. It seems to be possible but it is far outside the design envelope. That is why the flying supposedly done by complete novices on 911 stretches the imagination.

Are you that dumb He just disproved your "the plane can't do that theory"?

You have taken the word of one statement against the word of at least 3 pilots on here, so who still has there head in the sand?

[Edbear]

He said he had no real problems at far higher speeds in the sim, he isn't a practising pilot either by the sounds of it.

The pilots may not have had the experience many have, but have we heard exactly who they were? They did have training to a degree and the flight simulator report shows it's not necessary to be highly skilled to do what they did.

One can argue the matter until the cows come home, but the fact is, the WTC WAS hit, the Pentagon WAS hit and the third plane was on its way to its target. The planes did do what they did, so what they did was obviously within thier capabilities and the capabilities of the pilots. They did not perform impossible maneuvers, that's an oxymoron, nothing can perform impossible maneuvers, nor did they perform maneuvers outside their design envelope.

Conspiracy theorists would have us believe that the US Govt. used highly trained military pilots to pilot domestic aircraft into its highly valued, iconic and world-renowned status symbol/business centre, simultaneously triggering a pre-set demolition charges and kill 3,000 innocent civilians; at the same time flying a domestic air-craft into the Pentagon and attempting to do the same to the White House. Why? To provide an excuse to invade Irag.

Yup. Let's attack, kill and destroy our most prized and valuable targets, hitting the very heart of the US power and economy, so we can invade Iraq and get rid of Sadam Hussein.

Tui Ad, anyone..?

[Quasievil]

But the plane did fly into the WTC so whats the point of arguing its possibility, it happened

Albeit on a flying fox for guidance, didnt you silly pricks see the imagery that proves it

[oneofsix]

Well done, there is some sanity. It seems to be possible but it is far outside the design envelope. That is why the flying supposedly done by complete novices on 911 stretches the imagination.

he said it is within the design envelop but outside the safe operating limits. As these guys weren't interested in safe operation of the aircraft you need to forget the safe operating limits, after all I'm sure they also say don't fly into buildings.
Even IF it was out side the design envelop, so what? they didn't care. The craft will hold together beyond the design envelop and they weren't looking for a comfortable or safe flight.

[Edbear]

he said it is within the design envelop but outside the safe operating limits. As these guys weren't interested in safe operation of the aircraft you need to forget the safe operating limits, after all I'm sure they also say don't fly into buildings.
Even IF it was out side the design envelop, so what? they didn't care. The craft will hold together beyond the design envelop and they weren't looking for a comfortable or safe flight.

You make it sound like they didn't care if they crashed them and wrote them off...

[The Stranger:Me]

Well done, there is some sanity. It seems to be possible but it is far outside the design envelope. That is why the flying supposedly done by complete novices on 911 stretches the imagination.

Am I missing something?
Isn't the entire argument about capability of the planes moot?
I mean, the planes did hit the buildings right? Have I got that straight?
Because if they did, then surely they are capable of it so really does it matter what speed was estimated?

Last I heard (and I readily accept that I may well be wrong) but they are claiming not that the impact was the big problem, but the burning fuel. Now conspiracies aside, this is bourne out surely by the fact that the building did not tumble on impact, but some time later when either the fire had done it's bit or the charges went off.

[Virago]

As always, the two sides of this debate are completely polarised, and always will be.

The conspiracy theorists have made a huge leap of logic. One which requires them to believe that "TPTB" are constantly plotting to kill their own people, for various mysterious reasons. That every disaster, whether at man's hands or nature's, is part of a deeper plot that threatens us all. That it is all controlled by a mysterious "world order", who control the "puppet" leaders below.

Having made that leap of logic, the conspiracy theorists find themselves in a dark and fearful world from which there is little chance of rescue. They are beyond reason.

The parallels with religious fanaticism are hardly surprising. Luckily they can't burn the rest of us at the stake these days...