Runway designators

Runway Designators

Every runway carries a painted number that tells you its magnetic orientation at a glance — essential for choosing the runway into wind, reading aerodrome charts and understanding ATIS or tower instructions. The designation system is standardised worldwide in ICAO Annex 14, Vol I (runway designation marking), so a "runway 27" means the same thing at every aerodrome on earth.

How the number is derived

A runway designator is a two-digit number from 01 to 36 equal to one-tenth of the magnetic azimuth of the runway centreline, rounded to the nearest whole number. Single-digit results are written with a leading zero.

Because a runway can be used in both directions, it has two designators that differ by 18 (i.e. 180°): 09/27, 04/22, 16/34. Practical check in the cockpit: lined up on runway 27, your magnetic compass and heading indicator should show approximately 270°.

A runway aligned with magnetic north is designated 36 (for 360°) — the designator 00 is never used, so a runway with an azimuth of e.g. 003° also carries the designator 36.

Parallel runways

When two or more parallel runways share the same direction, a letter suffix distinguishes them:

• 2 parallel runways: L (left) and R (right) — e.g. 07L / 07R.
• 3 parallel runways: L / C / R (left / centre / right) — e.g. 07L / 07C / 07R.
• 4 or more parallel runways: the adjacent pairs are numbered one unit apart even though they are parallel — e.g. 06L/06R alongside 07L/07R.

Left and right are assigned as seen from the approach direction, so the suffixes swap with the direction of use: the runway that is 07L from one side is 25R from the other.

Europe (EASA / EU)

ICAO Annex 14 is applied EU-wide via Regulation (EU) No 139/2014 (Aerodromes — Part-ADR) and the associated certification specifications CS-ADR-DSN. EASA requires compliance with these standards at certified aerodromes; national authorities commonly apply the same specifications to non-certified aerodromes.

Germany (national)

Applied under EU law. Because magnetic variation changes over time, the magnetic azimuth of a runway slowly drifts — when it crosses a rounding boundary, the designator is reassigned (e.g. 09 becomes 08). Such changes are coordinated by the competent authorities and DFS and published in the AIP Germany and via NfL (Nachrichten für Luftfahrer).

Exam essentials

• A runway designator is one-tenth of the runway's magnetic azimuth, rounded to the nearest whole number, written as two digits from 01 to 36 (273° → 27).
• The two ends of the same runway carry designators differing by 18, i.e. 180° (09/27, 04/22, 16/34).
• A runway aligned with magnetic north is designated 36; the designator 00 is never used.
• Two parallel runways are distinguished by L and R, three by L, C and R.
• With four or more parallel runways, adjacent pairs are numbered one unit apart (06L/06R and 07L/07R).
• Runway designators refer to magnetic, not true, direction — they are reassigned when magnetic variation shifts the azimuth across a rounding boundary.