NORAD and how transponders work

[Edx]

I hate it when people pretend to be experts, they can easily make up all manor of crap and so you have to go to great lengths to find out exactly why they're wrong.

A truther (yea, the same one..) is now making claims about how transponders being turned off really isn't that big a deal.

I PM'd gumboot but I know a bunch of people understand this stuff in great detail as well so figured I'd ask, yet again. Its not like this forum has more interesting things to talk about

... Do you know how a transponder works? It works as an extension of radar detection, not as a separate system. When a radar sends a ping, it's not just a short burst of radio frequency. It's a short code. When transponder picks up that code, it sends a burst of its own, replying to the sent code and also encoding the squak code, and depending on the system some additional information that is difficult for radar to acquire. Mode C specifically, which is what required within 30nm of Class B sends back pressure altitude.

This is very important for the ATC operations in large airports. A squak code is used to identify aircraft, so that the ATC can give specific instruction to a specific blip on the screen. The altitude is important because radar cannot pick it up, and it's another piece of information that the ATC will require.

Now why am I claiming that it's a load of crap that they couldn't find a plane? What happens if I'm flying my crop duster, and I flew into a busy Class B airport area? Am I simply not going to show up on the radar screen which ATC are using to steer the planes? Are you seriously that naive? Do you know what will happen if that crop duster ends up on the path of a 747 going for final? You'll have 300 dead bodies. That's if the 747 doesn't end up dropping on a residential area.

Everything that's big enough to show up on radar shows up on the screen to which all the transponder data is fed. If something does not have transponder, it will be shown without a squak and without an altitude. You see a dot on your radar without a squak in Class B, you report it immediately, because it's a hazard to all aircraft in the area. That's how the system works. That's how people get busted for flying within 30nm of a Class B without a working Mode C Transponder.

And hey, I just checked the charts, and it's almost 50nm from Mode C boundary of Washington Dulles to Pentagon going from direction that AA 77 reportedly came in from.

 

[Edx]

bump - i highlighted the example of a situation I would like someone that knows to explain what would happen in such a case?

He also has this to say about Andrews:

No we'll play it like this, you claimed Andrews could scramble fighters at a moments notice, you say, in 5 minutes. Are you admitting you do not have any source for this claim?

Absolutely none. I know planes. I know if you don't scramble fighters on 5 minute notice, you don't need to bother. Tu-160 can cross the border going Mach 2. If the F-15s have to play catchup, they'll never make it to the bombers before they complete their mission.

If you have a source claiming otherwise, go ahead and give it.

What I want to know is what fighters were available to deal with threats like he is referring to if Andrews would have taken a long time to scramble fighters, which I know they would have taken.

 

[ElMondoHummus]

I know this doesn't directly address his post, but there are just a few things that should be known to put his claims in perspective:

1. FL175 never shut off its transponder, so it was indeed tracked.
2. FL11 was noted to be hijacked, and the FAA requested an aircraft scramble for it. NEADS had trouble locating it on primary radar. By the time Boston Center and NEADS had worked out how to communicate where FL11 generally (not specifically) was, it was too late, and FL11 hit the WTC 1 mere minutes later. If I'm reading Gumboot's timeline correctly, the Otis F-15s hadn't even taken off at that point yet.
3. For FL77, when the transponder went off, Indianapolis ATC Center presumed the aircraft went down, and began their search in the direction it was heading. Nobody thought to check primary radar in a completely different direction.
4. FL77 also entered an area with no primary radar coverage. This also is an additional reason Indianapolis Center thought it had crashed; at the time, they were not aware of what was happening on the East Coast.
5. Primary radar only shows returns; it does not show transponder data for known craft and then just blips for unknown craft. When an air traffic controller switched over to primary, he's presented with a screen full of blips, and has to work hard at reference which dots correspond to which aircraft. And in busy airspace - yes, the East Coast is very busy airspace - picking out one return among many is work, much less identifying which return is a hijacked aircraft. From the Vanity Fair Article:

   In order to find a hijacked airliner—or any airplane—military controllers need either the plane's beacon code (broadcast from an electronic transponder on board) or the plane's exact coordinates. When the hijackers on American 11 turned the beacon off, intentionally losing themselves in the dense sea of airplanes already flying over the U.S. that morning (a tactic that would be repeated, with some variations, on all the hijacked flights), the neads controllers were at a loss.
   
   "You would see thousands of green blips on your scope," Nasypany told me, "and now you have to pick and choose. Which is the bad guy out there? Which is the hijacked aircraft? And without that information from F.A.A., it's a needle in a haystack."

   And because they were still scrambling to identify aircraft amongs all the thousand-some in the air, the FAA just didn't get the information to NEADS in time, not to mention the fact that the FAA ATCs were still struggling to build a picture in real time as the event was happening. It will help to look up posts from Cheap Shot (Colin Scoggins) in this forum in addition to Gumboot's; Cheap Shot was the military liaison at Boston ARTCC on that day and because of that was actually involved in the event. And his posts are exceptional because of this.
6. By the time Cleveland ATC Center figured out that FL93 was hijacked and got the info to NEADS, FL93 had already crashed.

I don't know if you've seen Gumboot's timeline before, but:
http://www.internationalskeptics.com/forums/showpost.php?p=1845150&postcount=1

(If you already know about this, my apologies)
... and it's notable that identification of the aircraft due to transponder issues is only one of the factors that day that allowed enough time for 3 of the hijacked jets to make it to their targets. That guy needs to read the Vanity Fair article, and Gumboot's two threads (the timeline linked above, and "The NORAD Response").

 

[ElMondoHummus]

bump - i highlighted the example of a situation I would like someone that knows to explain what would happen in such a case?

He also has this to say about Andrews:



What I want to know is what fighters were available to deal with threats like he is referring to if Andrews would have taken a long time to scramble fighters, which I know they would have taken.

Andrews AFB was not an alert base in 2001. NEADS had to depend on Otis AFB and one other that I don't recall off the top of my head.

ETA: Aha. It was Langley. Link: http://www.911myths.com/index.php/Andrews_Air_Force_Base

 

[Reheat]

Like most twoofers, this guy knows just enough to be dangerous. I'll give you an initial response and someone else can add to it as it is quite involved. I'll try to keep it in layman's language as much as possible.

First of all, the thread title is misleading. This has more to do with the FAA and their Radars than it does with NORAD. We'll talk about 9/11 first and go from there.

NORAD did not monitor US Continental Airspace on 9/11. That was and is the responsibility of the FAA. It still is, but NORAD has better radars now than on 9/11 so that they can pick out a primary return (no transponder) much easier than on 9/11. On 9/11 the NEADS radar was not able to distinguish an aircraft return from the ground clutter in the NE area of the US. That's very simply why they could not identify AA 11 and UA 175. The FAA could and did follow the primary returns on both aircraft all the way into the NY areas until it was below radar detection range.

That's the first part. Now, while the FAA Radars do have the capability to to detect (see) a primary return they don't necessarily monitor that. In high level airspace (above 18,000' MSL) a transponder is required. Consequently, most controllers in the high level structure do not monitor primary returns (raw radar). They do have that ability and it only requires flipping a switch. As a routine matter they just leave the primary returns in what's best described as a standby mode, so their looking at only secondary returns (transponder). On the other hand, low level controllers (those in terminal areas) do keep their primary returns visible to them for the reasons your twoofer stated.

AA 77 was a special case in that the Indianapolis Sector monitoring the aircraft had ONLY secondary returns (not primary) available to them. I won't go into the technical reasons why. Other radars did track UA 77 entirely, but those radars were not available to the controllers responsible in real time. That's partly why they lost it when the transponder was switched off. However, UA 77 can be tracked using archived radar all the way from shortly after Take-Off to the DC terminal area just short of the Pentagon.

Now, Dulles TRACON did pick-up AA 77 because they were warned to be on the look out for it and they had their primary radar on as they normally would in a terminal area.

This is a quick and dirty explanation. If you don't understand, please ask and I or someone else will clarify the issue.

 

[ElMondoHummus]

Yes, Reheat and Beechnut are two other posters to pay attention to regarding this, as they're both ex-military aviators.

Granted, Beechy's old enough to have known the Wright Brothers, but still, he's ex-military.

 

[Edx]

Thanks for the responses, so what would you say would happen in the situation he gave?

Now why am I claiming that it's a load of crap that they couldn't find a plane? What happens if I'm flying my crop duster, and I flew into a busy Class B airport area? Am I simply not going to show up on the radar screen which ATC are using to steer the planes? Are you seriously that naive? Do you know what will happen if that crop duster ends up on the path of a 747 going for final? You'll have 300 dead bodies. That's if the 747 doesn't end up dropping on a residential area.

Obviously it will show up, but what happens if they can't contact it?

Is it just another hour and whatever before they get some fighters to go check it out like it was with Payne Stewart?

 

[Reheat]

What I want to know is what fighters were available to deal with threats like he is referring to if Andrews would have taken a long time to scramble fighters, which I know they would have taken.

Andrews AFB was not an alert base in 2001[/URL]. NEADS had to depend on Otis AFB and one other that I don't recall off the top of my head.

Correct, Andrews was an Air Combat Command base with an Air-To-Ground mission, not Air Defense. Langley AFB (South Dakota ANG) was the other NORAD based with Air Defense Fighters on alert.

Of course, there were many other units with appropriate Fighters, which were not on alert, consequently not armed. It takes hours, not minutes, to arm and launch a non-armed fighter depending on several variables.

 

[Reheat]

Thanks for the responses, so what would you say would happen in the situation he gave?

Obviously it will show up, but what happens if they can't contact it?

Is it just another hour and whatever before they get some fighters to go check it out like it was with Payne Stewart?

Your twoofer and perhaps you are confusing/mixing up NORAD and the FAA. For the Continental US, the FAA notifies NORAD (at least, they are suppose to) and NORAD responds or not appropriately.

Loss of radio contact is not that unusual and DOES NOT (contrary to twoofer myth) require a NORAD response unless it's in the ADIZ. In other areas it depends on whether or not it's considered a threat or has some other emergency that would necessitate an armed fighter response.

 

[Edx]

Andrews AFB was not an alert base in 2001. NEADS had to depend on Otis AFB and one other that I don't recall off the top of my head.

ETA: Aha. It was Langley. Link: http://www.911myths.com/index.php/Andrews_Air_Force_Base

So how long would it take for Langley to scramble fighters?

He claims in his situation: "Tu-160 can cross the border going Mach 2. If the F-15s have to play catchup, they'll never make it to the bombers before they complete their mission."

He thinks that less than 10 minutes to intercept and its too late.

 

[Edx]

Your twoofer and perhaps you are confusing/mixing up NORAD and the FAA. For the Continental US, the FAA notifies NORAD (at least, they are suppose to) and NORAD responds or not appropriately.

Loss of radio contact is not that unusual and DOES NOT (contrary to twoofer myth) require a NORAD response unless it's in the ADIZ. In other areas it depends on whether or not it's considered a threat or has some other emergency that would necessitate an armed fighter response.

Thanks for explaining this btw.

So what would happen in the situation of the "crop duster" pre-911?

 

[Reheat]

So how long would it take for Langley to scramble fighters?

He claims in his situation: "Tu-160 can cross the border going Mach 2. If the F-15s have to play catchup, they'll never make it to the bombers before they complete their mission."

He thinks that less than 10 minutes to intercept and its too late.

Hehehe...

The required response time for an Air Defense scramble is 15 minutes. They are usually faster, but 15 minutes is required.

He's leaving out a very important issue. Where/how far out would that Tu-160 be detected. Let me assure you it is further than he thinks. Think about it, if the Rusky bomber is doing Mach 2 and the F-15's or 16's are doing Mach 2, what is their closure rate? He probably can't figure that one out as most twoofers suck at math. That's why they're twoofers!

 

[MG1962]

Hehehe...

The required response time for an Air Defense scramble is 15 minutes. They are usually faster, but 15 minutes is required.

He's leaving out a very important issue. Where/how far out would that Tu-160 be detected. Let me assure you it is further than he thinks. Think about it, if the Rusky bomber is doing Mach 2 and the F-15's or 16's are doing Mach 2, what is their closure rate? He probably can't figure that one out as most twoofers suck at math. That's why they're twoofers!

Which why they call it an intercept and not a chase And why America along with lots of our countries HAVE MORE THAN ONE AIRBASE lol

 

[Reheat]

So what would happen in the situation of the "crop duster" pre-911?

Most folks who fly want to keep their license and avoid hefty fines, Consequently, they follow required notification rules.

If the crop duster did not follow those rules an AD fighter would (with a steely eyed smirk on the pilot's face) fire a missile up his butt.

Better yet, since it's a crop duster there would be more pleasure to see it shredded to pieces by the cannon!

Obviously, I'm joking.

Aircraft transiting the area of the crop duster would be warned to either be on the lookout for him (pilots do have eyeballs) or would be vectored to avoid the area of the crop duster.

The crop duster would be in big trouble with the FAA if he's in restricted/controlled airspace (most are below) and would be confronted by Law Enforcement after landing.

No, there would be no Air Defense response. That would be a huge waste of Taxpayer $$.

 

[ElMondoHummus]

So how long would it take for Langley to scramble fighters?

He claims in his situation: "Tu-160 can cross the border going Mach 2. If the F-15s have to play catchup, they'll never make it to the bombers before they complete their mission."

He thinks that less than 10 minutes to intercept and its too late.

Boston Center (the Boston Air Traffic Control center) notified NEADS (they're NORAD's "North Eastern Air Defense Sector") at 8:37am. Otis (not Langley) got it's jets in the air by 8:50am. That's pretty durn quick, actually. But unfortunately, Flight 11 had already hit the North Tower at 8:46am.

Now, there's a gap between FL11 being hijacked (8:13am) and Boston Center figuring it out (somewhere between 8:20 and 8:37). I'd have to cruise the threads and reread stuff to remind myself why there was a gap, but if you think about it, that's not a lot of time to figure something like that out. Remember: Once they ID'd FL11 as a hijack, the FAA moved pretty quick to let NEADS know, but they had to realize it was a hijack first.

There are threads here somewhere that'll explain what went on during that interim time.

ETA: Oh, Ps. Langley - NEADS didn't even try to get Langley involved until 9:07, and it was refused at first. Langley fighters never even got off the ground until 9:22. And as noted in Gumboot's timeline, those were routed out to the Atlantic to a holding area.

Seriously, Gumboot's timeline kicks butt at getting people up to speed on what happened that day from the perspective of the air traffic control system and NEADS. In conjunction with the Vanity Fair article and a few other smaller works, it's all the history anyone needs to understand things that day.

 

[ElMondoHummus]

If the crop duster did not follow those rules an AD fighter would (with a steely eyed smirk on the pilot's face) fire a missile up his butt.

What is it with you Air Force guys and "missiles" in the "rear"? Do you have to search for especially adventurous wives, or do you just surprise them when they least expect it?

 

[MG1962]

What is it with you Air Force guys and "missiles" in the "rear"? Do you have to search for especially adventurous wives, or do you just surprise them when they least expect it?

Na just find a compliant navy man

 

[Reheat]

What is it with you Air Force guys and "missiles" in the "rear"? Do you have to search for especially adventurous wives, or do you just surprise them when they least expect it?

Well, it doesn't absolutely have to be in the rear, the front is just as good especially if it's someone elses wife and particularly if one wants to avoid being put into a tight spot!

 

[George 152]

So how long would it take for Langley to scramble fighters?

He claims in his situation: "Tu-160 can cross the border going Mach 2. If the F-15s have to play catchup, they'll never make it to the bombers before they complete their mission."

He thinks that less than 10 minutes to intercept and its too late.

The bit he misses (and of course it's the important bit) is that this Tu-160 has a fair bit of time to get to the border.
Or does he think that bombers can't be detected on RADAR and intercepted ?

 

[gumboot]

So how long would it take for Langley to scramble fighters?

He claims in his situation: "Tu-160 can cross the border going Mach 2. If the F-15s have to play catchup, they'll never make it to the bombers before they complete their mission."

He thinks that less than 10 minutes to intercept and its too late.

Well let's look at this, shall we?

The radars NORAD would be using are the ARSR-4 long-range surveillance radar. Maximum range of the ARSR-4 is 460km.

A Tu-160 can indeed attain speeds in excess of Mach 2, however at these speeds it would exhaust its fuel supply in a matter of minutes. The Tu-160's cruising speed is approximately 850km/h.

This gives the USAF about 30 minutes to scramble and intercept before the aircraft crosses the coast.

Of course all of this is irrelevant. The Tu-160's primary armament is six Raduga KH-55s, which have an operational range varying from 600km to 3,000km depending on model. The Tu-160 would never even enter US radar coverage, let alone cross the coast.

At which point it's crucial to point out to people that at a peace-time level of readiness, NORAD's Air Defense System is not in any way whatsoever intended to protect the USA from attack. If the USA were to be hit by a surprise attack out of the blue there is absolutely nothing NORAD could do about it.

Rather it is anticipated that any sort of attack would arise from a long period of increasing tensions between the countries, and as such NORAD would be maintaining an elevated level of alertness with many more 1st Air Force assets at its command, CAPs, and AWACS platforms providing longer-range air surveillance (much like we saw during Operation Noble Eagle post 9/11).

Were the Russians to launch an air attack on the USA the US would detected preparations and launching in Russia, and thus would have hours, not minutes, to prepare a response.