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Terms used in unmanned air traffic

Some definitions and explanations of terms that are often used in the regulations for unmanned air traffic.

  • VLL: Very Low Level

International term that comprises «Non-standard» VFR or IFR operations under 500 feet AGL (AGL – Above Ground Level), including VLOS, EVLOS, and BLOS. This term has not been included in the Norwegian regulations as part of our guidelines. (VFR = Visual Flight Rules. IFR = Instrument Flight Rules.)

  • VLOS: Visual Line Of Sight

Flying an unmanned aircraft must be carried out so that the aircraft at all times is seen without visual aids such as binoculars, camera or other tools, except glasses. The aircraft must also be operated in such a manner so that collisions with other aircraft, people, vehicles, vessels, and ground construction can be avoided. Maximum height of operation in Norway is 400 ft. AGL, which is approximately 120 meters above ground level.

  • EVLOS/E-VLOS: Extended Visual Line of Sight

VLOS operations above 400 ft. AGL and/or where an agreement for maintaining visual control with the aircraft beyond the pilots line of sight has been acquired from Civil Aviation Authority.

  • BLOS: Beyond Line of Sight

Flying unmanned aircrafts beyond line of sight for pilot and/or observer. BVLOS/B-VLOS Beyond Visual Line of Sight. Subgroup/specification of BLOS, same criteria as BLOS.

  • BRLOS/B-RLOS: Beyond Radio Line of Sight

Subgroup/specification of BLOS where there is no direct link between ground station and the aircraft, and another form of relay is used (for example, Satcom, mobile technology, etc.). The aircraft can physically be VLOS/EVLOS, but is not considered an VLOS/EVLOS operation without specific approval.