GM1 Article 2(7) Definitions

CAA ORS9 Decision No. 16

DEFINITION OF ‘VISUAL LINE OF SIGHT OPERATION’- ‘CONTROL THE VISUAL FLIGHT PATH’

Being able to control the visual flight path of the UA means keeping it within a suitable distance of the RP, such that the RP can maintain control of the flight path of the UA, to avoid a collision with other aircraft, people, obstacles or the ground. This distance depends on a number of factors, including:

- The eyesight of the RP;

- The size of the UA;

- The visual conspicuity of the UA (colour, and contrast of the UA against the backdrop from the viewpoint of the RP);

- Any navigation lighting on board the UA;

- The weather conditions (fog, sun-glare etc);

- Terrain and any other obstacles that may obscure the view of the UA from the RP;

- Whether the operation is during the hours of daylight, or night. Although there are not specific limitations on operating at night, the visual conspicuity of the UA and ambient lighting, may affect the distance to which the UA may be flown from the RP.

This distance will likely vary on each flight depending on these factors, and the RP should be able to identify at what point VLOS can no longer be maintained.

Just because the UA is still visible (for example, a dot in the sky), this does not mean that it meets the definition of VLOS. A RP must be able to visually determine the aircraft’s orientation at all times. While this may potentially be aided by navigation lights, the sole use of telemetry to indicate UA orientation to the RP is not considered as acceptable.