VLOS: visual line of sight, and where 'seeing' stops
What VLOS means, what the rule actually requires, and when you leave it without noticing.
VLOS stands for Visual Line of Sight. It is flight during which the remote pilot keeps direct unaided visual contact with the aircraft, sufficient to control its path and avoid any obstacle.
That is the ICAO definition, and it is the same everywhere: Europe, the UK, North America.
"Unaided" is the word that catches people out
The rule does not merely require knowing where the aircraft is. It requires seeing it — with the naked eye.
So these do not count:
- binoculars and spotting scopes;
- the aircraft's video feed, which does not show what is arriving from the sides;
- a position on a map, which says where it is but nothing of what surrounds it.
Corrective glasses remain acceptable: they restore normal vision, they do not extend it.
There is no official distance
It is the most asked question, and the answer disappoints: no distance defines VLOS. The criterion is what the remote pilot actually perceives, and it varies with aircraft size, light, sky background and terrain.
A dark multirotor against a forest disappears well before a light-coloured aircraft against clear sky. National frameworks often add height ceilings — 120 metres in Europe — but those are separate limits, not a definition of visual flight.
⚠️ People leave visual line of sight without noticing: behind a building, into the sun, beyond a ridge. At that moment the operation becomes BVLOS and changes regulatory regime.
An observer does not replace the remote pilot
An observer can help, and some scenarios require one. But in ordinary visual flight it is the remote pilot who must see: delegating sight to someone else belongs to a different arrangement, framed and declared.
Going further
- BVLOS: flying beyond sight — what happens once you cross the threshold.
- Where can I fly? — zones, which are a separate constraint.
- Drone regulations in France.