GM1 Article 4(1)(d) Open Category UAS Operations
CAA ORS9 Decision No. 16
VLOS
In general, the UA must be kept within VLOS of the RP at all times, however provision is made in Article 4, which permits the UA to not be within VLOS of the RP when making use of a UA Observer.
A UA Observer may be used within the Open category, to assist the RP with keeping the UA in VLOS. Further information on the UA Observer may be found in section GM1 UAS.OPEN.060(4).