4.7. Visible line of sight (VLOS) vs beyond visible line of sight (BVLOS)

It is important to understand that there is a significant disconnect between what is technically possible and what is legal. Many drones equipped with cameras and autonomous flight capabilities could without modifications be flown outside visual range, but in most jurisdictions this is not legal without special permits or waivers.

‘Visual line of sight’ typically refers to unaided line of sight, meaning that while eye glasses and contact lenses are fine, binoculars, telescopes or other vision enhancing devices are not.

Permits or waivers which make it legal to fly beyond visible line of sight are possible but they typically come with many restrictions.

It is usually also not allowed to operate drones from a moving vehicle or it is allowed only in sparsely populated areas.


  1. Loss of control over drones. E.g. signal loss increases accident risks since pilots can not observe emergency landings.
  2. Fines and disruptions due to illegal flight operations.

Audit Steps

  1. Interview pilots and flightcrews about their adherence to visible line of sight rules and the restrictions regarding operating drones from moving vehicles.
  2. If the company has a permit or a waiver allowing it to fly BVLOS, review this document carefully and test for the compliance with restrictions listed in the document.
  3. If drones are controlled from moving vehicles question the legal basis for this.


drone audit program index