Does the 1:1 rule apply below 30 m altitude?

Yes — 1:1 means the distance always equals the altitude. Flying at 10 m means a 10 m minimum horizontal distance. The 30 m standard A2 limit is a minimum floor.

What if the 1:1 rule and the 30 m limit conflict?

Always apply the more restrictive of the two requirements. If altitude dictates a larger distance than 30 m — use the altitude-determined distance. Simply: always maintain the largest required separation distance.

A2 exam

1:1 rule

Horizontal distance to people — practical A2 scenarios.

A2STS editorial12 min readUpdated 29/06/2026

Contents

Format

The 1:1 rule is an A2 exam-specific concept: the aircraft must maintain a horizontal distance from people equal to or greater than its flight altitude. In other words, flying at 30 m altitude means maintaining at least 30 m horizontal distance from uninvolved persons.

This rule forms the basis of the minimum separation distance for C2-class aircraft in standard A2 conditions. It links altitude to the horizontal distance requirement.

Preparation

Use graphic examples to understand the 1:1 rule. Picture a right triangle: flight altitude = one leg; horizontal distance = the other leg. They are equal.

Exam questions often use specific numbers: the aircraft is flying at 50 m altitude — what is the minimum horizontal distance from people? Answer: 50 m.

Exam tip

Mistakes

The most common mistake is forgetting that the 1:1 rule applies in the standard A2 scenario, not in LSM. LSM allows 5 m regardless of altitude (but with a speed limit). These two scenarios must not be confused.

Another mistake is applying the 1:1 principle to all aircraft types. This is a specific C2-class with A2 certificate concept — it does not apply to C1, C0 or other categories with the same mechanics.

Mocks

In A2STS question sets, the 1:1 rule appears alongside the other distance rules: 30 m standard, 5 m LSM, 150 m from assemblies. You must be able to distinguish all three scenarios correctly.

For exam preparation, draw a diagram showing all A2 distance rules and their conditions. Visual learning is significantly more effective than purely text-based study for this topic.

Frequently asked questions

Does the 1:1 rule apply below 30 m altitude?: Yes — 1:1 means the distance always equals the altitude. Flying at 10 m means a 10 m minimum horizontal distance. The 30 m standard A2 limit is a minimum floor.
What if the 1:1 rule and the 30 m limit conflict?: Always apply the more restrictive of the two requirements. If altitude dictates a larger distance than 30 m — use the altitude-determined distance. Simply: always maintain the largest required separation distance.

Authority & sources

A2STS Editorial · Reviewed by: EASA UAS syllabus aligned