Radar Chaos


Guide arrivals and departures to their destinations while maintaining the required separation between all aircraft. Avoid terrain and restricted airspace.


There are three types of control that you can provide to aircraft in this application: direction, altitude and speed. These are implemented by clicking on an aircraft, which displays the control interface. Initially, when you 'mouse over' an airplane you will see a blue line, which indicates the aircraft's destination. Once you click, you will see the control interface.

An aircraft's direction (or 'heading') is controlled by simply dragging the white arrow to the desired direction. Altitude is assigned by 1000 foot increments, by tapping the up/down buttons. Speed is assigned by 10 knot increments, by tapping the fast/slow buttons. Assigned altitude and speed is displayed at the bottom of the control interface.

As a shortcut, you do not need to click 'submit', but simply 'mouse away' from the interface. The interface will close and all control assignments will then be applied to that aircraft.


In the advanced levels you will see red lines with arrows. These are called standard arrival routes. Standard Arrival Routes (STARs) guide arrivals into a "downwind leg" (i.e. pointing away from the airport). This is great for you, the controller. You don't have to do much to get these pilots prepared for final approach. They fly themselves.

You can then peel them off the STAR when it is convenient to do so, by giving a heading towards the localizer. On departure, you can use headings to avoid other aircraft and guide them to their outbound waypoints.


Arrivals will enter your airspace typically between 7000 and 10000 feet, depending on where they are arriving from. Since jets are much faster than 'props' and will often overrun slower traffic ahead, jets are given to you at a higher altitude. Bring all arrivals down to 3000 feet when safe to do so. This is the ideal altitude from which an arrival will commence their final approach.

In this application, departures will always exit at 10000 feet. This is not always easy to achieve, if a departure becomes 'stuck' beneath an arrival. Occasionally a heading will be required to safely climb an aircraft. Be sure to avoid areas of terrain. For example, an area marked '60' indicates the lowest altitude which aircraft can overfly it.


Speed is usually the last type of control you will perform on an aircraft. Altitude and vectors are your primary control elements. Speed is something that you might use after you have put a 737 too close behind a slower DH8 on the localizer. In the real world of air traffic control, pilots must not exceed 250 knots below 10000 feet, and must not exceed 200 knots below 3000 feet when in the vicinity of an airport. In this application, your rule is to ensure that all aircraft are reduced to a speed of 200 knots or less, prior to intercepting the final approach localizer.

Initially, it is my recommendation that you do not select 'realistic speed' from the Options page. Should you choose 'realistic speed', an understanding of the 'indicated-airspeed-true-airspeed' relationship is helpful. You need to understand that in the real world (and in this simulation), with an increase in altitude, groundspeed becomes greater than the speed shown on the cockpit readout to the pilot. So if a you assign a pilot at 10,000 feet a speed of 210 knots, you will observe a groundspeed of about 250 knots. At sea level, there is no error. Simple concept, but it does require getting used to. For example, in this simulation you will notice that an aircraft at 3000 feet who has been assigned an airspeed of 200 knots will show 210 kts on the radar display (and if you select 'realistic tags' from the Options page, you will just see '21' which is short hand for 210 knots.


When you tell a Boeing 737 to change heading, altitude or speed, it requires time for things to actually happen. This can be frustrating for the 'newbie' who knows nothing of air traffic control. After you give a pilot an instruction, expect to wait up to 15 seconds before you actually see a response to this. In particular, speed changes require time.

When a pilot is told to descend from 9000 feet down to 3000 feet, the pilot requires 5 seconds to reach forward and make the adjustment to the autopilot control interface. The aircraft then gently reduces engine power and lowers it's nose, which requires another 5 seconds. By the time you observe any change on the radar display, 15 seconds have gone by and you may be wondering if the pilot is even listening!

I recommend selecting 'realistic response delay' on the Options page. Without selecting this, these delays are unrealistically reduced, with the newbie in mind.


In the real world of air traffic control there are separation requirements that must exist between each and every aircraft. It is not simply enough for aircraft to 'miss each other'. There are two basic types of separation: lateral and vertical. If you have the necessary lateral separation, vertical separation is not needed, and visa versa.

LATERAL SEPARATION: In this application you must maintain a lateral distance of at least 3 miles between all aircraft, unless vertical separation exists.

VERTICAL SEPARATION: You must maintain a vertical distance of at least 1000 feet between all aircraft, unless lateral separation exists.



Take a look at the image below. You see three or four arrivals making their way towards the airport. Initially, they follow the red paths which are called STAR routes. These are designed to reduce your workload. The previous air traffic controller up the line instructed these aircraft to follow these routes, which lead the aircraft into a 'downwind' fashion, a heading that is opposite to the final approach path.

By keeping the aircraft on these routes, you do not need to assign any more heading changes than you require. In fact, with experience you will not need to give more than two heading assignments to each aircraft. Occasionally it becomes necessary to break an aircraft off of the STAR route, and this is done by assigning a heading by dragging the aircraft's direction arrow. As soon as an aircraft is assigned a new heading, they cease to follow the STAR path.

On the right side of the image below, you see an arrival on a southbound heading, descending out of 6,700 feet, with a speed of 250 knots. Initially the aircraft entered the sector descending only to 9000 feet (the previous controller gives propeller-driven aircraft to you at 8000 and jet traffic to you at 9000 or above). Because of the terrain that exists in the northeast corner of your sector, you would initially descend the aircraft to 6000 feet only. Once the aircraft is clear of the terrain as well as other traffic, descend the aircraft to 3000 feet. 3000 feet is an ideal altitude for an aircraft to commence final approach. However, to ensure a proper stable final approach path, the aircraft must intercept the final approach path at least 10 miles from the airport, indicated by the white 'V' on the localizer path.

Alternatively, you could get fancy and descend the arrival to 2000', which would allow you to turn them onto a much tighter final approach - about 7 miles final.

Once the arrival has passed the 10-mile mark, it is time to turn them 90 degrees (right angle) toward the final approach localizer path. If the aircraft is following traffic, especially slower traffic, you may need to 'extend the downwind' by letting the aircraft fly farther south before turning them. At this time, reduce the aircraft's speed to 200 knots or less. Although in real life pilots will do this on their own, in this application we assign it to them.

Below, you see the aircraft on the perfect 'base leg'. That is, they are at a 90 degree angle to the localizer, at 3000, speed is 200 knots or less, and they are slightly more than 10 miles from the airport, indicated my the mile dots on the localizer. (NOTE: You could also descend aircraft to 2000 and give them a 7-mile-long final approach).

Whenever you hover your mouse over an aircraft, you will see a blue line, which indicates the aircraft's destination. On more advanced levels that have multiple airports, this is invaluable!

Notice the conflict that exists over to the left. A fast jet is stuck above much slower traffic, likely a Cessna or Piper. Because of their proximity to each other, at least 1000 feet of vertical separation is required.

At this time the arrival is assigned 'heading 330', which is a 30 degree intercept to the localizer. You do not need to be exact with these headings, but your score will improve if you abide by the 'maximum 30 degree intercept' rule. You must also give the aircraft it's 'approach clearance' by selecting the Approach Clearance button on the control interface. Ultimately, the tower controller gives the pilots a 'landing clearance'.

Below, the aircraft is making a perfect intercept. It has everything it needs:

  • 30 degrees or less;
  • 3000 feet or less;
  • 200 knots or less; and,
  • A final approach path of 10 miles or more.

To the left side of the screen, you see that the stuck jet is now more than 3 miles from it's traffic. Vertical separation is no longer required and they can safely descend. In real life, more than three miles would likely be required for 'wake turbulence'. This ranges from anywhere between 3 and 7 miles, depending on the aircraft sizes involved.

The arriving aircraft has turned from it's 30 degree intercept and is now tracking final approach by following the localizer. At this time, in real life you would instruct the aircraft to contact the airport tower controller for a landing clearance. Your work is done. Once an aircraft is established on the localizer, refrain from assigning altitudes and headings. Speed changes are often necessary at this point. It is not uncommon to tell a jet to reduce their speed to 160 knots (the legal minimum speed assignment) if they are overtaking slower 'prop' traffic such as a Cessna.

Occasionally at this point, you may realize that your fast jet is overtaking slower traffic and a 'loss of separation' is inevitable. Your last resort is to cancel the aircraft's approach clearance. In such a case the aircraft would immediately climb to 3000 feet and await further instructions from you.

All aircraft reduce their speed as much as they safely can prior to touchdown. Although a Boeing 737 may intercept the localizer at 200 knots, they will eventually need to slow themselves to around 130 knots for touchdown. If you have two aircraft tightly spaced on the localizer, the second aircraft will gradually overtake the first as it slows down. This is known as 'compression'. It is a good idea to space similar-type aircraft 4 miles apart on the localizer. As the lead aircraft slows itself down, this 4-mile spacing will shrink a little.

The trickiest scenario is when a large jet aircraft must follow the slow Cessna. You will need to provide a great deal of room to protect for this 'overtake'.


Departures are much more straightforward than arrivals. Departures fly a path called a Standard Instrument Departure (or 'SID') which is usually nothing more than an assigned heading and altitude. At the airport below, you see a departure climbing northbound from the airport. The pilot follows the SID by flying a heading of 360, and by climbing to 7000 feet.

A SID is assigned by the tower controller. In real life, you would not assign any heading changes until the departure has climbed through at least 2000 feet. At that point, assign a direct heading to the aircraft's departure waypoint. Be aware of conflicting STAR paths and the altitudes of those aircraft. Your departing aircraft could be on a collision course with an arrival that you don't even see on your screen yet!

Once it is safe to do so, climb departures to 10,000 feet and ensure they exit in the appropriate area. Consider what jet traffic may exist off of your screen, in the next sector. The adjacent air traffic controller expects traffic from you at very specific locations and altitudes.

In the real world of air traffic control, prior to an aircraft exiting your sector, you would contact the next air traffic controller down the line and give them some warning, and visa versa, you would normally receive a warning before receiving traffic.


In this image, you may have noticed the red text that says, 'EMR' on an aircraft's data tag. This indicates that an aircraft is experiencing an emergency. In this simulation, there are two basic types of emergency, fatal and non-fatal. While all emergencies require you to give priority to that aircraft, certain emergencies are more critical than others.

If a pilot informs you that they have experienced an engine failure and need to land, they could likely fly on their remaining engine(s) for another hour if they had to. However, if a pilot reports "Fire on board" they need to be swiftly handled to the nearest airport for a landing.

In this simulation, it is expected that you will do just this. If an aircraft reports a emergency, open the control interface and select "Change Destination". Then, click on the nearest airport to make that their new destination. Depending on the severity of the emergency, consider giving the aircraft a 'tight gate', meaning a 7 mile final approach from 2000 feet. Less if necessary!