Attention, workload, vision
The whole ‘open’ category rests on two human resources: seeing, and staying focused. The regulation and its means of compliance treat them as measurable limits, not as moral qualities.
Key points
- AMC1 UAS.OPEN.060(2)(d) states three requirements: stay focused on the operation, do not fly while driving a moving vehicle, and operate only one aircraft at a time. The resource at stake is attention, which does not divide: ‘I can see both’ is not an argument.
- Visual line of sight is defined as continuous and UNAIDED visual contact (Art. 2(7)): it is therefore the remote pilot's own eyesight that carries the safety of the flight, not a sensor.
- GM1 UAS.OPEN.060(2)(a) counts among the causes of unfitness any physical or mental disorder and any functional limitation of a sensory organ that would prevent the operation from being conducted safely. The mention of sensory organs is not decorative.
- AMC1 UAS.OPEN.060(1)(c) asks you to be familiar with the light conditions of the site. A low sun can make the aircraft invisible in one precise direction: the one in which you are going to lose it.
- Loss of ORIENTATION comes before loss of sight: the practical self-training makes an exercise of bringing the aircraft back after placing it at a distance where its orientation can no longer be told apart.
- The same syllabus asks you to use external references to judge the distance and the height of the aircraft. Telemetry is an aid, never a substitute.
- Human reaction time is explicitly quantified in a distance calculation: AMC1 UAS.OPEN.040(1) assumes two seconds of reaction. At 19 m/s that is nearly 40 metres covered before the control input produces any effect.
- The unmanned aircraft observer stands alongside the remote pilot (Art. 2(24)) and clear and effective communication is required between them (UAS.OPEN.060(4)). You still have to agree on the vocabulary BEFORE the flight.
The trap. What the observer brings is not distance: it is attention, a second pair of eyes. Believing that he extends the range of the flight is the error GM1 UAS.OPEN.060(4) explicitly rules out.
Source
Implementing Regulation (EU) 2019/947 (CELEX 02019R0947, consolidated on 01/05/2025), art. 2, points 7) and 24), and Annex Part A, points UAS.OPEN.040(1), UAS.OPEN.060(2)(a) and UAS.OPEN.060(4); AMC1 UAS.OPEN.040(1), AMC1 UAS.OPEN.060(1)(c), AMC1 UAS.OPEN.060(2)(b), AMC1 UAS.OPEN.060(2)(d) and GM1 UAS.OPEN.060(2)(a) (ED Decision 2019/021/R); AMC2 UAS.OPEN.030(2)(b) (ED Decision 2022/002/R)