ATCC Controllers' Read Binder...

NOTAMS, FAQs and other info for users of ATCC

September, 1997

#1: Voice Upgrade Demo .WAV File

This is a short .WAV file containing sample speech from the upcoming voice upgrade. Click here to download. (18K)... It should start playing by itself. If not, save it to your hard disk and play it with any sound player. If your software doesn't recognize the compressed format, click here to download an uncompressed version. (85K).

The .WAV file is just a taped recording of the program, so you can't hear the cockpit noises too well, but they are there. The sound quality overall is remarkably similar to what comes out of actual Center radio equipment ("VSCS"), which is digitized and filtered to remove much of the static and noise.

The programming on the upgrade is currently focused on smoothing out some of the gaps between the numbers and words, and once that is completed, along with the ongoing testing, it should be ready for release.

Also, late this year IBM and several other companies should have their "continuous speech" voice recognition units on the market, which can recognize speech without the need to pause between words. We hope to have a driver written for those units soon after their release. The IBM unit is expected to sell for around US $200, including the headset. The less expensive versions (around US $50) should also work, but you have to add pauses between your words, which becomes very difficult when you are busy and want (need) to talk fast.

#2: Proper Spacing!

It is a primary requirement (after separation of aircraft), that you create the necessary in-trail spacing for those airports/routes that require it: 10 Miles to LAX in sector 19; 10 miles to ORD in 75; and 7 miles to JFK in sector 66. 9 miles to LAX is not good enough. 8 miles to ORD is not good enough. More than required is OK, but less is not. Yes, the next ATCC controller will still take the handoff if you don't get the spacing, but in reality you would be heckled over the interphone, your supervisor would be called and he would ask you why you're not adhering to the sector procedures. Spacing usually can't be compromised, because most of the major airports already run aircraft as tightly as they can get them in, and trying to squeeze the spacing a little just won't work. There is a lot of over-spacing, but very little under-spacing in reality. The best controllers are exact: neither over nor under. 10 miles exactly.

If you have chronic problems achieving the required spacing, you would probably be decertified and sent to the classroom for re-training. "Re-training" would probably mean sitting down with another controller/instructor, brainstorming ideas for getting and keeping spacing, and running simulations (increasingly soon on our ATCC program itself). These are a few spacing tips from real controllers:

  • For most of ATC, the earlier you do something or start it, the better. Except for spacing... if you start too early, such as at the western or southern boundary of sector 75, you'll likely find that errors in your distance measuring, or different tail winds, or slight variations in aircrafts' speeds (one could go mach .755, the other .764, both "technically" mach .76) result in different spacing than you anticipated -- you either get less spacing than you thought, or you over-restrict somebody and waste space, time, and fuel.

    If you start your sequencing too late, of course, you have to take more drastic actions (large turns) to get the spacing, and that can also be imprecise. Thus, there is some kind of balance you have to find: in sector 75, the "right time" to start spacing is probably around DBQ, unless they are already in a line and you can see the direct results; in sector 19, start sequencing right away, and in 66 you should probably wait until the oceanic arrivals are around MANTA or PREPI before you decide which gap to put them in.

  • When you're too busy to mess with the <F4> distance-measuring key, or things fall apart at the last moment (like you suddenly notice that "overflight" is actually an ORD arrival you have to fit in), you can play Follow the Leader, and create a "snake." With whatever physical space you have between two aircraft, regardless of which direction they're coming from, just point one at the other, and that distance will hold. For example, in sector 66 if you have one JFK arrival at DRIFT, and one at PANZE, both at the same speed and both direct CRI, point the aircraft at PANZE directly at the one at DRIFT (70 heading?), and you'll hold that spacing (roughly 15 miles). Then when the aircraft reaches DRIFT, keep turning him to follow the one in front, wherever he may be at that moment. You may have had to turn that one out to follow somebody else, but it doesn't matter. Just keep everybody turning to follow the one immediately in front of them, and you'll have the "snake," and the spacing between them will hold.

    Once the extra aircraft has been fit into line, or the chaos restored, the "snake" will continue for awhile, as you have to keep turning aircraft to follow the ones in front of them, until there is a big enough gap between new aircraft coming in, that you can keep them on course without them catching up to the tail end of the snake.

    The benefit of this technique is that it is very intuitive once you see how it works (it's confusing to read--once you've done it, it's easy, though) and it is easy and quick to see how much spacing you have without the <F4> key. The downside is that you have to manually turn everybody to keep them following each other, so you can make yourself very busy. Also, if you forget to keep somebody following the previous aircraft, creating extra space, the snake will grow larger as everybody else behind him will have to turn out the extra distance, too.

  • Don't trust datablock groundspeeds. They are calculated by a simple estimate of the speed based on previous radar hits. If a radar hit is missed, or the aircraft is in a turn, the groundspeed readout grows more inaccurate. Thus, if you have an aircraft merging into line, and you turn him to line up with everybody else, the groundspeed readout will drop drastically, then slowly catch up. For awhile you will think you have a massive overtake developing, and may feel compelled to unnecessarily slow down everybody behind him. That wastes space, adds to your workload, and is unnecessary.

    The most reliable way to determine their speeds is to ask the pilots (they could conceivably lie, but they don't). Also remember to take into account different altitudes-- 300 knots at 14,000 is faster than 300 knots at 10,000. But if they are close together in altitude and direction, 300 knots on the front guy and 300 on the back means they're at matched speeds, regardless of what the groundspeed readout says. And autopilots on the airliners are very precise, so you can expect them to do 300 knots exactly, not 302 or 299.

    The second most reliable way to determine if you have an overtake/undertake when your groundspeeds are erroneous (such as in a turn) is to compare the differences in spacing between the target and its previous histories. If one aircraft is moving 4 millimeters between updates, and the one in front is only moving 3mm, you have an overtake, even if the groundspeeds say they're matched.

    The ATCC groundspeed readout is actually pretty close to what the aircraft are doing, so the above may not apply, but the real-life groundspeed readout is almost useless once the aircraft start to turn, speed up or slow down.

  • None of these hints may help you! You have to develop methods that work for you, whether methods used by others, or completely unique to you, or combinations of both. If it works, and you get the correct spacing without over-restricting, then keep it! There are probably as many techniques as there are controllers, and each controller thinks his/hers are the best! (This author included, except his are the best).

#3: Good Judgement

You are always expected to use "good judgement," and if your "good judgement" and "common sense" says to bend or break rules or procedures, then you are authorized to bend or break the rules and procedures. Of course, you will have to defend your actions, but that should not be a problem if you honestly have good reasoning behind them. The FAA Order (#7110.65) governing all ATC regulations, in fact states to use "good judgement and common sense" above and beyond any rule or procedure.

This, of course, is because there will be situations that aren't covered in any rule book or list of sector procedures. Use your experience, your common sense, your knowledge of the sector (see "Be the Sector," August issue), something you encountered in Microsoft Flight Simulator, or something you saw on the television the other day, if you feel it is relevant (and accurate, of course). If you have a justifiably good reason for whatever you do, your supervisors will almost always support your decisions, and if you have a deal "for good reason," you probably won't be charged for it.

Following is a "common sense" quiz, in the cliched "serious answer/joke answer" format. All events actually happened-- see if your answers are "correct" :

#1: An SR-71 is screaming out of control toward your sector, one engine out and descending rapidly through 50,000 feet. The adjacent controller calls you on the interphone and says they don't know where the SR-71 is going or what it's doing. It appears to be headed straight for one of your jumbo DC-10's cruising along happily at FL330, but the SR-71 is going so fast you can't be entirely certain. The SR-71 advises they're unable to change course. If you gave the DC-10 a hard turn out of the way, you would likely have a deal with another aircraft going the opposite direction. Do you:

(A) Turn the DC-10 anyway, which would cause a side-swipe deal (3 miles), but would at least avoid a possible collision.

(B) Advise the SR-71 and DC-10 of each other, then obtain the SR-71's Fuel On Board, Souls on Board, Original Destination, New Destination, and New ETA as required in FAA order 7110.65.

(C) Tell both aircraft to "look out," then cross your fingers and hope for the best.

#2: An aircraft climbing out of FL200 reports "narrowly missing" a balloon that went "right over" their aircraft. You ask him the approximate size of the hot-air balloon, color, if they could see any people on board, and the approximate direction of flight (from the upper wind direction). The pilot replies that it was actually a "child's birthday foot, maybe orange," but sounds honestly concerned. Do you:

(A) Steer following aircraft around the estimated position and path of the balloon, as nobody knows what would happen if it were ingested into a jet engine moving at 500 knots.

(B) Warn following aircraft about the wild balloon, cautioning them not to pop it.

(C) Scratch your head -- who knew those little balloons could ever get up that high?

#3: You are at sector 19 and are completely overloaded. Every slot for LAX on the range marks is occupied, plus there are 4 more LAX arrivals descending on top of everybody. SoCal approach calls and says they now need 15 miles-in-trail. You are spending 90 percent of your time trying to explain to a very grumpy airline captain why he has to turn out to a 70 heading-- there just isn't room for him, and you assure him he'll get his turn back in just a few minutes. The pilot still grumbles, tying up your frequency and making you miss everything else you have to do: "We're running real late, can't you let us be #1? If we give you 340 knots, would that help?" -- You firmly state "NEGATIVE, TURN LEFT HEADING 070!", and the pilot replies "We're fuel critical-- we need to go in NOW." You ask the pilot if he is declaring an emergency, in which case you'd be glad to give him priority, and he just repeats: "We're fuel critical, we need to go in NOW." Do you:

(A) Ignore his whining, because if lack of fuel was truly a problem, the pilot knows he just has to say "emergency" and he'll be given top priority and a red carpet upon landing. But because he refused to declare an emergency, it's obviously just a ploy to cut to the front of the line -- if you let him get away with it, everybody else will try it too.

(B) Let him take somebody else's place in line, but advise him that because he apparently departed without the required amount of extra fuel to allow for moderate delays plus diversion to a backup airport, an FAA regulation was possibly violated and he'll have to call in after he lands.

(C) Let him cut to the front and go straight in, but make sure everybody else on frequency knows his flight number, so they can dispense their own sense of vigilante justice later in the pilots' lounge.

#4: You have two aircraft converging: an airliner at FL200, and a Lear Jet climbing to FL190, for now 10 miles apart, but will soon pass 3 miles apart at their closest point. Instead of stopping at FL190, the Lear pilot mistakenly keeps climbing-- now showing 196 and rapidly increasing. There's no chance of a collision, but the datablocks will start blinking and you'll lose your 5 miles at any moment. Do you:

(A) Say nothing -- there's no chance for collision, and both aircraft see each other -- so when the deal is investigated, it will be filed under "pilot error," which is what it truly is.

(B) Tell the Lear to keep climbing to FL230 (which will technically make it your deal), because the Lear is probably already above FL200 by now, and it doesn't make sense to descend him through the airliner's altitude a second time.

(C) Ask the Lear pilot to "Verify you have been and are still level at FL190," and keep saying "I missed that, say again?" until the pilot gets the hint and says "affirmative." If the pilot reports a different altitude than what the radar shows, you technically have to discard the radar data and go by what the pilot says. Thus it is not a deal, nor is it a pilot deviation. Everybody's happy!


Surprise, everything is correct. It is a matter of what you feel is proper for the situation, and all answers are justifiable in some way (4-C?!), and would be supported by any decent supervisor.

For the record, situation #1 was handled by answer C(!?), and the other situations have taken place at various times with all answers used.

#4: Real-Life Radar Equipment

In the U.S., some new radar equipment ("DSR") is slowly being phased in, though most Centers will have the existing consoles for a couple more years. The current equipment, of course, is as you see it in ATCC, and does work. But it is old (a "mainframe" computer with a whopping 16MB RAM), and sluggish (most computer entries, such as TEMP altitudes, take about 3-5 seconds to process, so if you are a fast typist you just jam everything up and end up retyping anyway). Now comes new technology, with billions of dollars of research, color monitors, and fast response times, right?

Hmmmmm.... monitors/radar still monochrome; D-side's monitor just an off-the-shelf 15" VGA... computer response times of 6-12 seconds... the suppliers say it "meets specs," but the controllers' union ( says it's unsuitable in its present form.

In any case, once it is installed, ATCC will be modified with a downloadable upgrade, or new program version to conform to the new display and computer entries. It's still at least a year away, though.

One good thing about the new setup is that the home enthusiast can create a nearly identical console. The main monitor is a 2048x2048 Super-Super-SVGA type, 27 inch, that just sits on a table. The keyboard is the typical IBM keyboard, but with a second row of function keys. Strips are printed out entirely in black-and-white. Everything else is black-- black monitor, black keyboard, black (plastic?) strip rack. We'll try to get some scanned pictures for the next newsletter.

Any readers not in the U.S. should please stop laughing. We know you already have better radar screens and software, but for us it will be an interesting, and overdue change...

#5: More on ALT-P

ALT-P unplug is a cheat, of course, because it will work even if you don't have a D-SIDE sitting next to you to "take over." You are supposed to be honest about it... and really shouldn't use it at all.

You shouldn't need to, actually! If you are running the sector properly, everybody is separated at all times (i.e. positive separation), so whether the radar fails, or you need to quickly run to the bathroom, or to answer the phone, you can do so with no danger of a deal.

It's somewhat done in real-life, too... if the sector is relatively slow (say, 5 or less aircraft), and the controller wants to quickly pour another cup of coffee, he can get up and stretch his headset cord out to about 30 feet (10m) before having to unplug. Or even if somebody unplugs for a quick second, to get another pencil, for example, nobody looks twice.

So you can just get up and leave for a quick second, and still be true to the simulation, without ALT-P'ing. If the pilot complains about your not answering him as he kept trying to call you, just tell him you were busy "on the landline" (interphone) coordinating a direct routing for him, then give him direct somewhere, and he'll never know!

#6: Some Q&A

Q: What is Xavius Software?

We are a small company originally formed for contract and project programming, mostly for short-term business and technical software. One of the programmers, Christopher Coon, developed ATCC between other projects, while also working as a real-life controller, and upon its completion became the project manager. ATCC wasn't created to satisfy sales quotas or cash flow, but rather as a solid simulator designed as reality, and not market research, demanded (market research certainly would have demanded "things crashing and exploding," but that's just not the reality). "It's a cool program," is the explanation given for its existence, sales and support.

One of our other projects of interest to ATC enthusiasts is special effects/programming for an upcoming TV movie (currently filming) called "Blackout," to be aired on NBC in the U.S., probably next spring. It's about a Chicago Center Controller who has a mid-air collision in sector 82. ATCC controllers will recognize the southwest corner of sector 82, as well as some of the other "background" sectors possibly (75, 66 and 97; yes we know they're in New York, but just pretend!). A few of those details had to be Hollywood-ized (like puffier datablocks to make them readable), but most things look very realistic. They did use a real controller as a technical consultant, so the proper technical dialog is there too (we'll see if the actors say it correctly, though). It's been another of our "fun" projects.

Q: Who are you?

Me, the author? Actually I'm several people, with topics chosen by the ATCC group, mostly the program author, plus users, and real controllers. Sections are gathered together and usually typed or edited by Chris Coon or Jim Ziemer, who strive to post it on the 1st of the month, but always get distracted by some other problem, project or issue that can't wait another day (sorry, we'll keep trying).

If you ever have a procedural question, general ATC question, topic you'd like to see discussed, or if you're a real controller and would like to share your opinions/techniques (every controller has strong opinions!) we'd love to hear them, and would like to incorporate them in our newsletters. The FAA does have a policy that its controllers can only talk about things that make people feel "uplifted and optimistic about the FAA, air travel, and the future of aviation," so anything you may say can and will be anonymous. We're not particularly focused on either the good or bad aspects of ATC, just the practical reality... Suggest whatever you'd like to see!

Q: Explain this web site.

The most annoying part of the Web, everybody here unanimously agrees on, are the awful pauses when accessing data that may be on the other side of the planet. Not just "downloading," but even just making a connection, keeping a steady flow of data, and getting a reponse from the other end. Everybody knows this -- you know this -- and with so many potentially interesting links and sites and net search info, there is nothing more frustrating than waiting even just 60 seconds, an huge amount of time when you have 50 sites you want to visit, only to get a useless graphic of a blinking arrow with cached effects that makes your hard drive spin endlessly.

So we just put up text, just the info, with minimal graphics, to try to speed things along somewhat, if only a little. But if people -- you -- prefer to see things blinking, and 3D click here 's, and frames and all those other effects, we can put them in. mailto:

#7: They're Just Blips

All-in-all, even though ATCC may be just a simulation, most real-life controller users do agree it curiously captures the whole phenomena of a radar controller's sense of reality. Probably many (most?) Center controllers, unable to see, hear, smell or otherwise sense the reality of what's really going on, somewhere in their minds just see the computerized blips as computerized blips and nothing more, and are so trained to keep them 5 miles/1000 feet apart by speaking commands into a little tube laying across their cheek, that the absurd surreality is never an issue.

A controller can sit months and years on end in front of the scope, turning blips left, right, watching datablock numbers go up, down, talking into the little microphone, hearing disembodied voices respond in the earpiece, and never think a thing about it.

Then the controller goes to a major airport, on a trip across country, as a regular passenger. The huge drama every aviation/scanner/airport enthusiast knows is completely engulfing: thousands and thousands of people, rich, poor, big and small; Luggage in piles, people on cell phones, at payphones, walking everywhere; P.A. announcements every 5 seconds, rumbling roars of huge jets shaking the whole building... Then on the plane, listening in to ATC (most UAL aircraft), the nonstop deadpan chatter on Ground control, huge cruise ships of aircraft shuffling in and out of the gates, taxiways and runways, seemingly just barely missing each other, but all movements gracefully choreographed.

Then airborne, climbing out, through the same sectors the controller works day after day--- and the controller's voice he hears in that monotone rapid-delivery, that can't be the same goofball he goes to the bar with after work, is it?? Everybody sounds so official, so calmly professional over the radio, and everbody knows exactly what they're doing and is obviously focused 100 percent on the safety and separation of that aircraft.

Then later in the evening, a descent into a cloud layer: sudden darkness out the window, and the flight attendant hurries to the front, darkening the cabin lights -- the passengers sit all alone, silently, hanging on tight as rain pelts against the windows, the aircraft creaking and lurching left, then right, suddenly dropping, then the engines whine and rev to life, the pitch higher and higher, louder and louder (my God, we're gonna crash!) ... Then poof! Out of the clouds, quietly now and gently floating over a miniature model of a city, grids of amber lights slowly scrolling across the window; then the machine-gun voice of Approach turning aircraft one-by-one to downwind; then left heading 090; then cleared visual runway 36 left... then on final, looking out the window at strings of solid white lights suspended in mid-air, a dozen more aircraft lined up and stretching out and up into the clouds.

Then it's back to work at the same ole' radar, moving the little green backslashes around and not thinking a thing of it... right?


The Read Binder is updated at the beginning of the month. All information is for use with Xavius Software's Air Traffic Control CenterTM only, is the opinion of the author(s), and does not necessarily reflect the policies or practices of the U.S. Federal Aviation Administration or Federal Aviation Service. Send your questions or comments to and we're happy to respond!