Detection Line of Sight (DLOS) and Ground Visibility

In plain language

DLOS is how far you can fly and still spot other aircraft in time to get out of the way. It depends on visibility, and you may never assume more than 5 km.

Requirement as structured

DLOS is defined by EASA guidance as the distance up to which the unmanned aircraft could theoretically fly while other aircraft in the same direction can still be visually detected with sufficient time for an avoidance manoeuvre; ground visibility is crucial for this. Ground visibility should be determined at the time of operation, the procedure for determining it should be described in the operations manual, and the maximum ground visibility to be assumed is 5 km, analogous to VFR visibility in airspace G1.

Original regulatory text

Detection line of sight (DLOS): The DLOS defines the distance up to which the UA could theoretically fly while at the same time other aircraft in the same direction can be visually detected, and sufficient time is available for an avoidance manoeuvre. The ground visibility is crucial for this. Ground visibility (GV): The GV depends on the operational area and the meteorological conditions, and should be determined at the respective time of operation. ... The maximum ground visibility to be assumed is 5 km, analogue to the visibility according to the VFR rules in airspace G1.

Applies when

operation

VLOS

regulatory category

Specific