AVI310101
Three-Digit Bearings
Three-Digit Bearings
Picture This
You are an air traffic controller at Sydney Approach. On your radar screen, 23 aircraft are converging toward the airport. Two of them — QF401 and VA218 — are closing in on the same airspace, 40 seconds from conflict. You need to turn QF401 now. Every second you spend thinking about which direction to say is a second those two aircraft get closer together.
In maths class, you may have seen direction bearings like N40°E or S25°W. Aviation does not use them. Here is why:
Direction bearing (e.g., N40°E) requires 3 mental steps:
Identify the reference direction — is it North or South?
Identify the rotation direction — towards East or West?
Process the angle between them.
Three-digit bearing (e.g., 040°) requires just 1 step after training:
Fixed reference: always North.
Fixed direction: always clockwise.
One number to process.
The Three Rules of Three-Digit Bearings
Always measured from North
Always measured clockwise
Always written as three digits (e.g., 045°, not 45°)
Cardinal directions:
North = 000° (or 360°)
East = 090°
South = 180°
West = 270°
Use the interactive compass below to explore how bearings work:
Bearing Explorer
Visualise three-digit bearings on a compass. Toggle trig mode to see sin/cos component decomposition. [avi-bearing-explorer]
Reading Bearings & Quadrants
Intercardinal Directions
NE = 045°
SE = 135°
SW = 225°
NW = 315°
How to Read Bearings Aloud
ICAO Radio Phraseology
In aviation radio communication, bearings are spoken digit by digit:
320° → "three-two-zero"
045° → "zero-four-five"
270° → "two-seven-zero"
008° → "zero-zero-eight"
NEVER "three hundred twenty" or "forty-five". There's no time for multi-syllable number words when aircraft are converging.
Every Syllable Counts
Two aircraft are converging. The controller has seconds to act:
"Qantas 401, turn left heading two-seven-zero, immediately."
The pilot hears 3 digits, instantly pictures due West, and begins the turn. Saying "two hundred and seventy degrees" is 11 syllables instead of 3. In the extra time, both aircraft travel another 2 km closer together.
Quadrant Identification
Quick mental check — which quadrant is a bearing in?
000°–090° → NE quadrant
090°–180° → SE quadrant
180°–270° → SW quadrant
270°–360° → NW quadrant
Practice: Place the Plane
Now test your understanding! A plane departs on a given bearing. Tap the compass to place it at the correct position.
There are no angle labels on the compass — use the tick marks. Each major tick mark is 30° apart.
Three-Digit Bearing \u2014 Tap to Place
Place the plane by tapping the compass at the correct bearing. No angle labels \u2014 use the tick marks!
Exercise: Tap to Place
Place the plane at the correct bearing on the compass.
Random bearings — auto-next on answer.
Practice: Identify the Bearing
Now try the reverse! A plane is already on the compass. Work out its three-digit bearing from the airport.
Remember: bearings are always measured from North, turning clockwise.
Identify the Bearing
A plane is shown on the compass. Work out its three-digit bearing from the airport.
Exercise: Identify the Bearing
A plane is shown on the compass. Type its three-digit bearing.
Random bearings — auto-next on answer.