# BVLOS Unmanned Aircraft Operations in Forest Environments
## 3 BVLOS Operations  
BVLOS operations are attractive within forested environments because they remove the need for any pilot or visual observer to maintain VLOS with the aircraft and the surrounding airspace. Technically speaking, even basic prosumer-grade unmanned aircraft are capable of BVLOS flight. However, they lack the technical capabilities to mitigate ground-based and airborne risks to the extent necessary to do this in a compliant manner with  
Figure 1: Visual depiction of how easily VLOS can be lost in forest environments.  
-aviation regulations. The regulatory environment and how to take a risk-based approach to allow for safe BVLOS operations are outlined in the following sections. However, this section elaborates, to a greater detail, how BVLOS operations can look in forested areas and how this overcomes many of the challenges within this operating environment. Real examples are given based upon operations that have been carried out or discussed by the authors within New Zealand and Pacific Island Nations.  
One of the first aspects to highlight about BVLOS is that there is variation with regard to the distance between the pilot and the unmanned aircraft. This influences the degree of usefulness of BVLOS for some operations, as well as the degree to which key technical and operational mitigations must be applied to be able to do those operations safely. While not recognised formally in the literature, the authors have observed a distinction between \"Soft BVLOS\" and \"Hard BVLOS\" within practitioner circles, and the terms are useful for understanding different risk profiles for BVLOS operations based upon how far the aircraft travels beyond VLOS. Soft BVLOS can be thought of as BVLOS operations that are carried out within a range that would be considered for VLOS operations, but the view of the aircraft and surrounding airspace is occluded by objects and terrain such that VLOS is not achieved. Hard BVLOS are operations that are carried out over long distances, which require significant equipment enhancement to be achieved safely. These two different situations are represented, in Figure 2, with an example of an operation that takes place within a 500 m radius of the operator standing on two skid sites (timber landings) at either end of an area of interest and an operation carrying out a roading survey across a large forest estate that spans between two cities within New Zealand.  
Figure 2: Diagram demonstrating the principles of Soft BVLOS (**Left**) and Hard BVLOS (**Right**).  
To expand upon the concept of Soft BVLOS vs. Hard BVLOS, two scenarios are provided that are typical scenarios that might be faced within the forestry sector. The example Soft BVLOS scenario is an unmanned aircraft flight covering a mature stand of trees on flat terrain, surrounded by stands of equal age that will be assessed, with only forest roads and a small skid site to take-off from. The Hard BVLOS scenario is a flight over a large forest estate that will be assessed, with mixed age classes and species, ranging from flat to hilly terrain, and the far end of the forest is 60 km from the take-off location. Both scenarios would be taking place in uncontrolled (Class G) airspace. A summary of these two scenarios can be found in Table 2.