Wtc 2

[jaydeehess]

Could someone steer me to the radar data for the aircraft that hit WTC 2(Flt 175?)

I wish to be able to show what altitude this aircraft was as it came closer to the WTC, ie. was it diving? and the velocity that the radar shows it was doing.

Along the same lines does anyone have info on the ability of a 767 to acellerate from say 300 MPH to 450MPH?

How long does it take for a 767 to acellerate from zero to take-off rotation speed?

[jaydeehess]

ahh good old 911research.com
http://911research.com/planes/attack/flight175.html#ref8
Flight 175 apparently flew in a southwesterly direction as it crossed the Hudson River, continued into New Jersey until it was southwest of New York City, and then made a sharp turn to the northeast in order to approach the World Trade Center from the southwest. According to the NTSB Report on Flight 175, the plane started a turn to the northeast at 8:57 and descended from 28,000 feet as it approached the World Trade Center.

[Reheat]

As you've determined the power response (acceleration) issue for a 767 is a moot point. Crips, he could have used idle power and accelerated to Mach 1 if the airframe had held together and it didn't tuck on him.

He obviously did what Hani was afraid to do at the Pentagon, but I'll admit I don't know his distance from the WTC when he began that horrendous descent.

[sylvan8798]

As you've determined the power response (acceleration) issue for a 767 is a moot point. Crips, he could have used idle power and accelerated to Mach 1 if the airframe had held together and it didn't tuck on him.

He obviously did what Hani was afraid to do at the Pentagon, but I'll admit I don't know his distance from the WTC when he began that horrendous descent.

What do you know about the claims that they (the pilots) couldn't override the automatic system which would prevent them from going this fast at this elevation, etc. etc.?

[Reheat]

What do you know about the claims that they (the pilots) couldn't override the automatic system which would prevent them from going this fast at this elevation, etc. etc.?

What are you talking about?

[triforcharity]

Its BS. The pilots can override just about any system they cant that directly controls flight. Autopilot will be disengaged if someone touches the yoke enough.

So, in conclusion, its BS. Tell that idiot that they are ignorant of flight systems.

[jaydeehess]

What do you know about the claims that they (the pilots) couldn't override the automatic system which would prevent them from going this fast at this elevation, etc. etc.?

You are thinking of a different aircraft type.

The 767 has no ability to override what the pilot is instructing the aircraft to do.
The pilot will see and hear warnings about exceeding Vmo and imminent collision but if the pilot is unconcerned about the racket they will make the aircraft will be as dumb a machine as 16 oz. claw hammer.

The 767 is non-FBW aircraft.

[ElMondoHummus]

What do you know about the claims that they (the pilots) couldn't override the automatic system which would prevent them from going this fast at this elevation, etc. etc.?

I bet that stems from people finding that Airbus jetliners do that. Or at least, they did; others here with more knowledge can update me if things have changed. Anyway, there are some famous Airbus accidents stemming from the system not paying attention to pilot input; I think one was at a French airshow (will Google in a bit). Thing is, that's lazy research on truthers parts; the jetliners that were involved in 9/11 were Boeings, not Airbuses, and such issues don't apply to them.

ETA: Aha! Air France A320, 1998 (http://aviation-safety.net/database/record.php?id=19880626-0). Initial reports from the pilot were that the plane ignored throttle input. From what I'm reading in a quick Googlewhacking, though, that doesn't seem to be the issue. So maybe that airshow crash isn't a good illustrative example.

At any rate, while others may bemoan the fact that Airbus jetliners will ignore pilot input in certain circumstances, the fact remains that they only do so when the input is beyond the capabilities of the jet. And another fact is that too many accidents occur due to pilot error, not system error. So while I personally like the Boeing idea of soft limits that are overridable, I can't fault Airbus for going in a different direction.

[/derail]

[sylvan8798]

What are you talking about?

Ok, this is from another poster:

http://messageboards.aol.com/aol/en_us/articles.php?boardId=564809&articleId=47035&func=5&channel=]

http://en.wikipedia.org/wiki/United_175
"From the time, at approximately 08:58, when Shehhi completed the turn toward New York to the moment of impact, the plane went into a sustained power dive, descending more than 24,000 feet in 4 minutes 40 seconds, for an average rate of over 5,000 feet per minute.[13] New York Center air traffic controller Dave Bottiglia reported he and his colleagues "were counting down the altitudes, and they were descending, right at the end, at 10,000 feet per minute. That is absolutely unheard of for a commercial jet.""

That is apparently 49 miles in 4.7 minutes, which means the plane would have to be going 10.4 miles per minute, or 625 mph. It is claimed that a 767 simply cannot fly straight-ahead at over 500MPH, near sea level, in thick air of about 1.2kg/cubic metre, let alone in a high g turn outside "velocity never exceed" software limits designed to prevent the aircraft breaking up in flight.
Boeing 767 Max. Cruise speed Mach 0.86 (493 kn, 568 mph, 913 km/h at 35,000 ft cruise altitude)

[jaydeehess]

The aircraft impacted WTC 2 at 9:03:40 so that's 5 minutes and 40 seconds from 8:58 that gives 518 MPH and one notes that the time given for the radar is "approximately 8:58" .

If 8:58 is actually 8:57:30 it translates to 476 MPH and if the 49 miles distance is not quite right, say its 48.5 miles (the ATC quote does not give a distance, where are you or the other poster getting 49 miles for this descent?)it translates to 471 MPH. If its actually 48 miles then its down to 467 MPH

If the clocks are different by 1 minute then its all the way down to 400 MPH.

Try again? At 35 miles and 4min40sec Its 450 MPH

see how an error range affects things? (You probably don't, do you? You are probably thinking that I am just playing with numbers to obfuscate the issue and throw you off. Is that assessment close?)

The 'never exceed" speed you refer to is probably the Vmo. That is the speed that the manufacturer gaurntees the aircraft to operate perfectly. It is NOT the speed at which the aircraft starts to come apart at the seams. In fact aircraft flight testing takes them up to 0.95 Mach for , IIRC, 15 minutes, and they must survive this with no structural or control surface damage before they will be certified as airworthy.

In fact aircraft incidents have recorded aircraft doing very close to Mach 1 and surviving to land safely.

[Reheat]

Ok, this is from another poster:

Others have already answered your question correctly.
5,000 FPM descend rate is rather steep for a transport category aircraft, but it is within reason for someone who doesn't care about passenger comfort.

The thick air and all of that other "twoofer" stuff does make going fast more difficult, but not impossible particularly in a power dive such as 175 did.

I have no trouble at all believing the speeds. They only intended to do it once!

[ElMondoHummus]

If there are "software" limits, then people have to remember this about Boeing FBW design: Boeing sets a "soft" limit that can be overridden by the pilot. It's not a hard limit that treats pilot input in extreme maneuvers as "less credible" (that's actually a term I recall seeing used on a posting board about the Airbus 1998 airshow crash). So if such a limit exists (Reheat, Beechnut, others: You'll have to tell me if that limit truly exists), it can be overriden because the pilot retains final say as to what control inputs are.

Reheat, Beech, as pilots yourselves, can you confirm or correct that? That's what I'm seeing on the net, but I'm no pilot myself.

[Reheat]

If there are "software" limits, then people have to remember this about Boeing FBW design: Boeing sets a "soft" limit that can be overridden by the pilot. It's not a hard limit that treats pilot input in extreme maneuvers as "less credible" (that's actually a term I recall seeing used on a posting board about the Airbus 1998 airshow crash). So if such a limit exists (Reheat, Beechnut, others: You'll have to tell me if that limit truly exists), it can be overriden because the pilot retains final say as to what control inputs are.

Reheat, Beech, as pilots yourselves, can you confirm or correct that? That's what I'm seeing on the net, but I'm no pilot myself.

I don't know about Boeing's "software limits", but I do know about the methods used by General Dynamics/Lockeed-Marietta for both the F-111 and F-16.

Their method is to simply prevent the aircraft from exceeding a critical angle of attack. The Flight Control Computer will not allow the horizontal stabilizer (for the layman that would serve the same function as an elevator) to move to a position which would cause the aircraft to exceed it's critical angle of attack. The cockpit flight controls feel and react the same as they normally do, but the computer simply will not send the command to the stabilizer to exceed the critical angle of attack at any speed.

For example, the aircraft can be flown with the stick full aft and the aircraft in a controlled slightly nose down attitude, yet the aircraft will not stall or enter a post stall gyration. It will descend at a horrendous rate, but remains stable and controllable throughout. The pilot has no override, nor is one needed. Perhaps the easiest way to think of it is to realize it is simply a "stall inhibitor system". It prevents flight into regimes where no one wants to go anyway.

Since GD/LM have over 25 years experience with this type of system, my guess is that Boeing uses the same on their FBW aircraft, perhaps even subcontracting it.

[Reheat]

It's past edit time, but I've a bit to add to the above comments.

I can not conceive of an aircraft manufacturer that would impose "limits" to flight control authority within the normal envelope of an aircraft's capability. That simply wouldn't make sense even with an override present. I also can not conceive of a Professional Pilot who would accept such a contraption to fly in the first place.

I've read the accident report of the Airbus that ElMondo referred to, but it is confusing and not very specific about the throttle restriction in terms of what it actually does and why it was designed into the aircraft. I'd certainly need more information about how it actually works and what it is suppose to accomplish before expression an opinion about it.

It does make perfect sense to impose limits at the very edge of aircraft capability limits. A lot more good people would be alive today if the type of system I've referred to above had been present when they inadvertently exceeded the aircraft's capability and crashed.

Any system which limits pilot input within the normal capability of an aircraft is more likely to cause more accidents than it prevents notwithstanding an override switch.

[ElMondoHummus]

I'm starting to see that even when keeping things simple and superficial, I'm out of my depth :o. The more I read about Boeing's "soft limits", the more I realize that it's not really applicable to the discussion here like I thought it would be. Like you said, it's simply a design that prevents flight controls from exceeding the performance envelope. Heck, a couple of boards discussing this even call it "envelope protection".

I found discussion of Boeing's philosophy in several links, like these:
http://www.airliners.net/aviation-forums/tech_ops/read.main/160009/
http://www.skybrary.aero/index.php/Fly-By-Wire#Control_Laws
http://cf.alpa.org/internet/alp/2000/febfbw.htm

... and all of these discussions are centered around severely exceeding safe performance envelopes like the ones set for a given aircraft's safe angle of attack, not merely going faster than what the plane is designed for.

Peh... I'd better cede the field to the more knowledgeable. Thanks for the info, Reheat!

[ElMondoHummus]

Blah! You posted while I was writing! :)

It's past edit time, but I've a bit to add to the above comments.

I can not conceive of an aircraft manufacturer that would impose "limits" to flight control authority within the normal envelope of an aircraft's capability. That simply wouldn't make sense even with an override present. I also can not conceive of a Professional Pilot who would accept such a contraption to fly in the first place.


Right. I'm now realizing that not even Airbus does this. If one reads "Boeing vs. Airbus" sites as a layman like me, the rhetoric and hyperbole some employ might lead one to think that Airbus does indeed override and interfere much. That's the popular myth that is behind the Airbus accident I referred to earlier. But I've since discovered that this is not so; the system is like Reheat said: Protection against exceeding the performance envelope.

The links I added above go into a bit more detail on this. And like I said, I'm no expert. I'm only repeating what I've found online.

[Reheat]

The links I added above go into a bit more detail on this. And like I said, I'm no expert. I'm only repeating what I've found online.

I had not previously read at any of those links. I think you have a better understanding than you're admitting.

Assuming that the comments on those Forums are correct, Boeing's implementation of FBW is actually getting more into the realm of automated flight. There are computer inputs designed to make the pilot's job "easier", but in that the inputs are "soft" in that they can be overridden by the pilot. Airbus' inputs can be overridden too, but in a different way. The manufacturers are not really implementing "limits" as much as they are implementing "strong reminders" via control forces that what the pilot is attempting to do is "not normal".

You ARE CORRECT in thinking that this type of technology would have made the speeds we see on 9/11 more difficult, but not actually impossible. Apparently, the 777 will automatically attempts to prevent an overspeed (exceeding Vmo) by making automatic inputs, but it can be overridden.

Just to make it perfectly clear, NONE of the aircraft used on 9/11 had any of these automated inputs we're discussing. They had hydraulically assisted flight controls such as we've seen since shortly after WWII.

To go a bit further.....

Even tho' remote control has been in operational existence for at least 40 years, we are nowhere near implementing that in passenger carrying airliners. That may eventually happen, but I seriously doubt any of us will ever see it in our lifetime.

[sylvan8798]

The aircraft impacted WTC 2 at 9:03:40 so that's 5 minutes and 40 seconds from 8:58 that gives 518 MPH and one notes that the time given for the radar is "approximately 8:58" .

If 8:58 is actually 8:57:30 it translates to 476 MPH and if the 49 miles distance is not quite right, say its 48.5 miles (the ATC quote does not give a distance, where are you or the other poster getting 49 miles for this descent?)it translates to 471 MPH. If its actually 48 miles then its down to 467 MPH

If the clocks are different by 1 minute then its all the way down to 400 MPH.

Try again? At 35 miles and 4min40sec Its 450 MPH

see how an error range affects things? (You probably don't, do you? You are probably thinking that I am just playing with numbers to obfuscate the issue and throw you off. Is that assessment close?)


No need to get in a sarcasm lather jaydeehess. Let me make it clear, if it wasn't before, that I am not a truther. Certain posters on other boards always make these various claims regarding things I have no real expertise in, however, and I don't have a technical response for them. My background is in structural engineering, mathematics, and general physics.

People on here who ARE experts are able to shed light on these things. If asking them for assistance is a no-no, or a sign of trutherism, then I will certainly desist.

And yes, btw, I get your point about the effect of a small variation in the times.

[jaydeehess]

Ok, my response was a reaction to having seen so many truthers argue with no sense whatsoever about the effect of variables in calculations. My bad, I apologize.
:blush::(


ElMondoHummus writes:
people have to remember this about Boeing FBW design
nitpick: I believe that the 767 and 757 are not actually FBW in that the computer is not the arbitor of what the a/c does in terms of flight controls.

In my understanding of FBW the pilot 'tells' the aircraft where he wants the a/c to go(ie. up and to the right) by moving his controls and the computer then decides on the best way to have this accomplished in adjusting the control surfaces. In non-FBW the pilot is moving his controls and the control surface is directly linked to the pilot's controls.(even if it is via servos being controled by yoke movements rather than steel wires and pulleys)

For eg. in FBW the pilot pulls the yoke back corresponding to an incease in angle of attack of x degrees but the computer decides if perhaps adjusting another surface other than the elevator would accomplish this more efficiently than just the elevator.
In non-FBW this movement of the yoke would only and always result in just the movement of the elevator.

In both cases a computer could be designed to limit the range of use of the controls but in true FBW, since the computer is already issuing the final orders its much easier and is not an add-on other than in terms of software.

If the Airbus incident you speak of is the one I saw it occured when Airbus was showing the new model 300 (IIRC) to prospective buyers at Airbus's own test runway. Several high end prospective buyers actually were on board to experience the demonstration, others were in the stands next to the runway.

The pilot brought the a/c in at a high angle of attack and very slow to demonstrate it stability at low speed due to the corrections to flight surfaces that its new FBW system was constantly performing. When the pilot neared the end of the runway he was flying over he opened the throttles hard to get full power and demonstrate the a/c's ability to go to full power. However, according to the pilot the a/c instead never answered this call for full power(or at least it hesitated). the a/c continued to descend and went slowly down ito the trees, crashed and caught fire immediatly.

The supposition was that the FBW assumed it was landing and had to 'think' about this rash action of going to full power by which time it was taking the tops off of the trees.

In another incident a plane descending slowly from cruise altitude had its FBW system deploy the clamshells (ie. throw the engine thrust into effective reverse). The pilots fought their own aircraft for several minutes being tossed about the sky until it was eventually 'convinced' that it was not in fact landing.

Airbus removed many of the pilot overrides in its software after pilots unions started making noise about refusing to fly them until they had full control IIRC.

BTW the CT I am speaking with about this on another forum claims that MS flight sim will not allow the a/c to exceed Vmo and he assumes that this is how the real aircraft operates as well. He also claimed that to get to 450MPH as he got to Manhattan, (from cruise speed I suppose) he would have had to go to full power starting near Buffalo:D

I replied;
If it started at 360 MPH (what did we say cruise speed was again?) and ended up at 450 MPH over a 6 minute period then that equates to an average acelleration of just over 0.01g

[beachnut]

Ok, this is from another poster:


Originally Posted by AYoung2084
http://messageboards.aol.com/aol/en_...nc=5&channel=] (http://messageboards.aol.com/aol/en_us/articles.php?boardId=564809&articleId=47035&func=5&channel=])

http://en.wikipedia.org/wiki/United_175 (http://en.wikipedia.org/wiki/United_175)
"From the time, at approximately 08:58, when Shehhi completed the turn toward New York to the moment of impact, the plane went into a sustained power dive, descending more than 24,000 feet in 4 minutes 40 seconds, for an average rate of over 5,000 feet per minute.[13] New York Center air traffic controller Dave Bottiglia reported he and his colleagues "were counting down the altitudes, and they were descending, right at the end, at 10,000 feet per minute. That is absolutely unheard of for a commercial jet.""

That is apparently 49 miles in 4.7 minutes, which means the plane would have to be going 10.4 miles per minute, or 625 mph. It is claimed that a 767 simply cannot fly straight-ahead at over 500MPH, near sea level, in thick air of about 1.2kg/cubic metre, let alone in a high g turn outside "velocity never exceed" software limits designed to prevent the aircraft breaking up in flight.
Boeing 767 Max. Cruise speed Mach 0.86 (493 kn, 568 mph, 913 km/h at 35,000 ft cruise altitude)



The poster made up the 49 miles? Where did he come up with the figures? The poster pulled the speeds out of hearsay statements.

There are no never exceed limits in the 767/757. .

The 10,000 feet per minute is not based on real hard numbers. I would have to see the RADAR data to check the speed and descent numbers. But there is no speed limit to stop the plane from going past MACH 1 in a steep dive. And the engines have enough thrust to accelerating

Flight 77 from hard data

9:37:14 305 KIAS (knots indicated) 67/79 percent on engines
9:37:17 318 KIAS engines at 100 percent, push up took 3 seconds to spool up.
9:37:44 463 KIAS engines reading 99.5 and 98.8 percent.

30 seconds to go from 305 KIAS to 463 KIAS for flight 77 in a shallow dive. These are the facts and if an airliner could not accelerate this fast we would all die on the runway when the aircraft is dirty (flaps down, landing gear down). A clean airliner (flaps up, landing gear up, speed brakes down) is FAST and will make MACH 1 if the engines could and the controls work. The thick air stresses the airframe more, and rips off parts hanging out, or skin sections in the areas of most dynamic pressure.

I exceeded Vmo in the KC-135 in seconds from 300 KIAS at 500 feet and I had old weak engines about 11,000 pounds of thrust per engine. We needed 4 engines.

77 was making 5.27 knots per second, and accelerated 158 knots in 30 seconds; 911 liars can't do math.

[jaydeehess]

Thank you Beachnut for that.
On your advice I googled 767 dive limit and found an account of the suicide crash of EgyptAir 990;

The following is an account of the last moments in the 767 flying as EgyptAir 990 in which the pilot (Batouti) committed suicide(taking all on board with him,including the co-pilot Habashi)

At 22,000 feet and in a dive with the engines at idle, the aircraft hit Mach 1 and did not come apart immediatly (it did later after the co-pilot actually managed to recover from the dive)



Batouti said, "I rely on God." Then two things happened almost simultaneously, according to the flight-data recorder: the throttles in the cockpit moved back fast to minimum idle, and a second later, back at the tail, the airplane's massive elevators (the pitch-control surfaces) dropped to a three-degrees-down position. When the elevators drop, the tail goes up; and when the tail goes up, the nose points down. Apparently Batouti had chopped the power and pushed the control yoke forward.....
............Habashi was clearly pulling very hard on his control yoke, trying desperately to raise the nose. Even so, thirty seconds into the dive, at 22,200 feet, the airplane hit the speed of sound, at which it was certainly not meant to fly. Many things happened in quick succession in the cockpit. Batouti reached over and shut off the fuel, killing both engines. Habashi screamed, "What is this? What is this? Did you shut the engines?" The throttles were pushed full forward—for no obvious reason, since the engines were dead. The speed-brake handle was then pulled, deploying drag devices on the wings.

At the same time, there was an unusual occurrence back at the tail: the right-side and left-side elevators, which normally move together to control the airplane's pitch, began to "split," or move in opposite directions. Specifically: the elevator on the right remained down, while the left-side elevator moved up to a healthy recovery position. That this could happen at all was the result of a design feature meant to allow either pilot to overpower a mechanical jam and control the airplane with only one elevator. The details are complex, but the essence in this case seemed to be that the right elevator was being pushed down by Batouti while the left elevator was being pulled up by the captain. The NTSB concluded that a "force fight" had broken out in the cockpit.

Words were failing Habashi. He yelled, "Get away in the engines!" And then, incredulously, "... shut the engines!"

Batouti said calmly, "It's shut."

Habashi did not have time to make sense of the happenings. He probably did not have time to get into his seat and slide it forward. He must have been standing in the cockpit, leaning over the seatback and hauling on the controls. The commotion was horrendous. He was reacting instinctively as a pilot, yelling, "Pull!" and then, "Pull with me! Pull with me! Pull with me!"

It was the last instant captured by the on-board flight recorders. The elevators were split, with the one on the right side, Batouti's side, still pushed into a nose-down position. The ailerons on both wings had assumed a strange upswept position, normally never seen on an airplane. The 767 was at 16,416 feet, doing 527 miles an hour, and pulling a moderately heavy 2.4 gs, indicating that the nose, though still below the horizon, was rising fast, and that Habashi's efforts on the left side were having an effect. A belated recovery was under way. At that point, because the engines had been cut, all nonessential electrical devices were lost, blacking out not only the recorders, which rely on primary power, but also most of the instrument displays and lights. The pilots were left to the darkness of the sky, whether to work together or to fight. I've often wondered what happened between those two men during the 114 seconds that remained of their lives. We'll never know. Radar reconstruction showed that the 767 recovered from the dive at 16,000 feet and, like a great wounded glider, soared steeply back to 24,000 feet, turned to the southeast while beginning to break apart, and shed its useless left engine and some of its skin before giving up for good and diving to its death at high speed.