GM1 UAS.OPEN.030(1) UAS Operations in Subcategory A2

CAA ORS9 Decision No. 16

OPERATIONS IN SUBCATGORY A2

Subcategory A2 addresses operations during which flying close to people is intended for a significant portion of the flight. The minimum horizontal distance from uninvolved people is 30m. The RP is also required to have successfully passed an additional examination (known as the A2 CofC) in order to fly in sub-category A2.

The 1:1 ‘rule’

The ‘1:1 rule’ is a principle which can be used to identify when the minimum separation distance from uninvolved people may need to be increased, and by how much. It is based on the relationship between the UA’s height and its distance from the uninvolved person (the 1:1 line).

Image showingf a graph to demonstrate the 1:1 rule. On the y axis is the UAS height, on the x axis is distance from people; a 1:1 line helps to identify when the minimum separation distance from uninvolved people may need to be increased, and by how much.
The horizontal separation between the UA and uninvolved people should not be less than the height of the aircraft. The higher the aircraft, the further it will travel should it suffer a catastrophic failure, and therefore the higher the likelihood of it colliding with uninvolved people, and so the separation distance must be increased (or the height reduced). This is so that, in the event of a propulsion failure, the UA is not likely to fall in an area with uninvolved people present.

RPs should aim to maintain a horizontal separation distance that is greater than, or equal to, the aircraft’s height, using the same units of measurement.

Operations where the aircraft’s height is greater than the separation distance (i.e. above the 1:1 line) should be avoided or kept to the absolute minimum time necessary, due to the increased risk.