# BVLOS Unmanned Aircraft Operations in Forest Environments
## 4 The International Regulatory Environment
They should also listen to the local air band radio frequency to assist with situational awareness when operating outside of shielded areas: areas that are shielded by obstacles such that no manned aircraft could reasonably enter them [21]. To achieve BVLOS operations that are compliant with the requirements of Class G airspace, the unmanned aircraft will need to have the technological capability of fulfilling the'see, detect, and avoid' principle, which is commonly referred to as Detect And Avoid (DAA) systems. The next section outlines some of the technologies that might be used to make this case. However, operations may also take place in controlled airspace. If this is the case, then, the operator will need to obtain permission from Air Traffic Control (ATC) and comply with any requirements [32]. In many respects, controlled airspace is easier to operate BVLOS within because ATC can ensure separation between the unmanned aircraft and manned aircraft that might be operating in the area. However, this does not mitigate the need for some onboard technologies to enable visibility of the aircraft for Secondary Surveillance Radar (SSR) so that ATC can see the location, speed, and heading of the aircraft [33]. Nonetheless, very few forested areas will be within controlled airspace, so this is an unlikely operating environment. Finally, BVLOS operations can take place within restricted airspace or other forms of segregated airspace [34]. These require the administering authority's permission to be able to enter them. With enough forward planning, it may be possible for the owner of a forestry estate to apply to have a restricted airspace above their estate so that they become the administering authority. This restricted airspace may be either temporary or permanent in nature. While, again, countries may have differences in how easy it is to apply for restricted airspace, the decision typically hinges upon whether the restricted airspace would pose a significant interruption to manned aircraft operations in the area [20]. Accordingly, the ability to get the restricted airspace is a lot easier in remote areas where there are no extant manned aviation operations. The advantage of restricted airspace is that the operator only needs to be able to ensure that ground risks are managed and that the aircraft will not leave the boundary (in terms of area and altitude) of the restricted airspace. This avoids the need for complex DAA systems because there is no potential for collision with manned aircraft, but it does not remove the need to mitigate other risks [21]. Some countries, such as Australia, also treat remote airspace in a similar manner to restricted airspace and allow for BVLOS operations without DAA systems. However, there are very tight bounds around such approvals [35]. Outside of airspace requirements and preventing collisions with manned aircraft, most countries will have requirements around how risks to people, property, and terrain are mitigated. Typically, these aspects are already somewhat managed by the operating environment. In the case of privately-owned forest estates, the owners can ensure that there are no workers present within the operational area, effectively reducing the potential to injure people to zero (excluding those involved with the operation). Even if they are public areas, the concentration of people within the area will likely be very low. Similarly, the damage that could be done to property is limited to damaging trees or terrain, as forest environments will not typically contain privately occupied dwellings. Nonetheless, there may be exceptions that require specific mitigations to reduce ground risks (people, property, and terrain). As highlighted in extant literature, these mitigations sometimes overlap with reducing airborne risk, while others are specific to only ground risks [21; 36].