Visual line of sight, and what breaks it
Visual line of sight is the condition that holds up the whole ‘open’ category: it is what stands in for radar, air traffic control and anti-collision. Two words of its definition do most of the work in the examination: continuous, and unaided.
Key points
- Article 2(7) defines a visual line of sight operation as one in which the remote pilot is able to maintain continuous unaided visual contact with the unmanned aircraft, allowing him to control its flight path in relation to other aircraft, people and obstacles, for the purpose of avoiding collisions.
- Article 4(1)(d) makes it a requirement at all times of the ‘open’ category, subject to two reservations it names itself: the follow-me mode and the use of an unmanned aircraft observer. Outside those two cases, losing visual line of sight means leaving the category.
- The purpose counts as much as the contact: catching sight of a dot in the sky is not enough if you can no longer judge its position relative to obstacles and to other aircraft.
- The video feed and binoculars do not restore visual line of sight: they replace it with something else, which the text does not allow.
- No distance figure exists: AMC1 UAS.OPEN.060(2)(b) explains that it depends on the size of the aircraft and on the characteristics of the environment, including visibility and the presence of tall obstacles. The 500 metres that circulate are not a VLOS limit.
- The unmanned aircraft observer stands alongside the remote pilot and observes with the naked eye (Art. 2(24)). GM1 UAS.OPEN.060(4) says it plainly: his role is not to extend the range of the flight. Point UAS.OPEN.060(4) requires clear and effective communication between them.
- In first-person view flying, the remote pilot remains responsible for the safety of the flight: the observer assists, he does not take his place.
- The first of the two flexibilities, the follow-me mode, applies only in subcategory A1: the aircraft then stays within 50 metres of the remote pilot (UAS.OPEN.020(3)). The second, the observer, does not extend the range of the flight: he helps to keep visual line of sight, he does not replace it.
The trap. The set-up that comes back every year: a relay of observers posted along a route. It does not make a beyond visual line of sight flight legal (the observer is defined as standing ALONGSIDE the remote pilot, and GM1 UAS.OPEN.060(4) denies him any visual aid) save for the emergency situation that same GM reserves, that of binoculars helping to land the aircraft far from the pilot. If you can no longer see the aircraft, the flight is over.
A diagram goes with this card: see it in the We Drone app.
Source
Implementing Regulation (EU) 2019/947 (CELEX 02019R0947, consolidated on 01/05/2025), art. 2, points 7) and 24), art. 4, paragraph 1, point d), and Annex Part A, points UAS.OPEN.020(3), UAS.OPEN.060(2)(b) and UAS.OPEN.060(4); AMC1 UAS.OPEN.060(2)(b) and GM1 UAS.OPEN.060(4) (ED Decision 2019/021/R)