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CENTERFIELD TRACON

Controller's handbook — read before your first shift

1. Your job

You are the approach controller for Centerfield International (CTR), the airport in the middle of your radar scope. Arriving aircraft check in from the edges of the scope. Your job is to vector them — issue headings, altitudes and speeds — until they are lined up with the runway, then clear them for the ILS approach. Once an aircraft is established on the approach and reaches short final, the tower takes over and the pilot lands the airplane. Your work is done when the wheels touch down.

The airport has a single east–west runway usable from both ends: Runway 9 (landing toward the east, heading 090) and Runway 27 (landing toward the west, heading 270). You may use either end — but aircraft approaching opposite ends fly head-on at each other, so plan carefully.

2. Reading the radar scope

• The white bar at the center is the runway; the dashed lines extending from each end are the final approach courses, with tick marks every 5 NM.
• Rings mark 10 and 20 nautical miles from the field; the numbers around the edge are compass bearings.
• Each aircraft is a square blip with a velocity leader showing where it is headed, a short trail showing where it has been, and a data block: DAL212 over 054↓21 — altitude in hundreds of feet (5,400 ft, descending) and speed in tens of knots (210 kt).
• Data block tags: ILS = established on the approach, TWR = handed off to tower, LF = low fuel.
• Colors: green = under your control, white = selected, blue = on the ILS, red = losing separation.

The simulation runs at 8× real time, so a 250-knot jet crosses your scope in about two minutes. Think ahead.

3. Controlling an aircraft

Click a blip on the scope (or its flight strip on the right) to select it, then use the AIRCRAFT CONTROL panel:

Command	What it does
HDG	Type a heading (001–360) and press SET, or use the arrow buttons for 10° / 30° turns left and right. Issuing a new heading cancels any approach clearance.
ALT	Climb or descend in 1,000-ft steps, between 1,000 and 12,000 ft. Aircraft climb and descend at realistic rates — they need time and distance to lose altitude.
SPD	Adjust assigned speed in 10-kt steps within the aircraft's limits. Slowing an aircraft is your main tool for spacing a line of arrivals.
APP	ILS RWY 9 / ILS RWY 27 clears the aircraft for the approach. CNL cancels a clearance (possible until tower handoff).

4. Getting an aircraft onto the ILS

An approach clearance alone does nothing — the aircraft must intercept the final approach course. To become established, at the moment it crosses the dashed centerline the aircraft must be:

1. Between about 1 and 22 NM from the runway threshold, on the approach side;
2. Within about 1.3 NM of the extended centerline;
3. Heading within 45° of the runway course (a 20–30° intercept works best);
4. At or below 4,500 ft, and below the glideslope — roughly 300 ft per NM from the runway. A good gate: 3,000 ft at 10 NM.

If the aircraft reports "too high for the approach", descend it further or turn it away, re-sequence, and try again. Once established, the aircraft flies the ILS by itself: it tracks the centerline, descends on the glideslope and slows to approach speed. At 7 NM it switches to the tower and is cleared to land — from that point its fate is out of your hands.

5. Separation — and what happens when you lose it

• Keep aircraft at least 3 NM apart laterally or 1,000 ft apart vertically. Violating both at once triggers a flashing red conflict alert and warning tone.
• If two aircraft close within about 0.8 NM and 400 ft, they collide. Both are lost. You are allowed to let this happen — the scoring will not be kind.
• Every aircraft arrives with limited fuel (shown on its flight strip). At low fuel it declares MAYDAY; when the tank runs dry it goes down. Don't leave anyone circling forever.
• An aircraft that drifts off the edge of the scope diverts to another airport — a smaller penalty, but no landing for you.

6. Scoring and levels

Event	Points
Landing	+100
Crash (collision or fuel exhaustion)	−200
Diverted off-scope	−50
Level passed	+1 per second left on the clock

Level 1 gives you 5 arrivals and a generous clock. Each level adds two more aircraft, shrinks the gap between arrivals, tightens fuel, and mixes in fast heavy jets and slow props whose speeds don't cooperate. To pass a level you must land at least 70% of the arrivals before time runs out; passing unlocks the next level, and your score carries over while you keep passing. Progress and the high score are saved in your browser.

7. Keyboard shortcuts

Key	Action
Tab / Shift+Tab	Cycle through aircraft
← / →	Turn 10° (with Shift: 30°)
↑ / ↓	Climb / descend 1,000 ft
[ / ]	Speed −10 / +10 kt
9 / 7	Clear ILS runway 9 / runway 27
C	Cancel approach clearance
P	Pause

8. Controller's tips

• Pick a landing direction early and build one orderly line — a downwind, base and final pattern, just like real approach control.
• Start descents immediately. An aircraft at 9,000 ft needs roughly 20 NM of track distance to get down to the glideslope.
• Slow the leader, not the follower — approach speeds differ, and a 737 will eat a Caravan's spacing on final in under a minute.
• Use both runway ends only when the arrivals come from opposite sides and you can keep the finals from meeting in the middle.
• Aim for 1,000 ft of vertical separation while sequencing; it lets aircraft cross paths safely.
• Low on time or fuel? Tighten the pattern — a 10 NM final is a luxury, 4 NM is enough if the aircraft is low and slow.

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