Let’s Learn from Australia: BVLOS Scenarios based on SORA
Updated: Dec 10, 2022
In this article, we investigate the existing BVLOS regulation from the Civil Aviation Safety Authority (CASA) in Australia, to help inform what future regulation here in the UK might look like. Of course the density of air traffic and of population on the ground are very different in Australia and in the UK. However, the risk assessment performed by CASA in the creation of each of the ‘standard scenarios’ has been done following the SORA (Specific Operations Risk Assessment) methodology, and we understand that the UK CAA will broadly follow SORA. And these scenarios have been used commercially with now return of experience, which is valuable insight.
In August 2021, CASA released a suite of BVLOS ‘standard scenarios’ to allow for the streamlined application for approval of operations with characteristics matching one of the scenarios. The risk assessment for each of the scenarios has already been performed by CASA, allowing applicants to simply meet application requirements by simply following a 'recipe'.
The following scenarios are currently active:
· AU-STS 1: Near a vertical object over a controlled ground environment that only involves active participants
· AU-STS 2: near a vertical object over a sparsely populated ground environment
· AU-STS 4: in a remote area within 3 nautical miles of a registered or certified
· AU-STS 6: below 400 feet above ground level (AGL) in remote Australian airspace, that is defined by CASA as locations with very low population density and low risk of aircraft encounters
· AU-STS 7: above 400 feet AGL and up to 5000 feet above mean sea level (AMSL) in remote Australian airspace, that is defined by CASA as locations with very low population density and low risk of aircraft encounters
Note: in this article, active participants are defined as those directly involved with the operation of the drone or fully aware that the drone operation is being conducted (i.e., they are aware of and have accepted the risks involved with the drone operation).
Note: 1 nautical mile is approximately 1.15 miles
Below, you can find a summary of each of scenario, along with its scope and restrictions.
AU-STS 1: Near a vertical object over a controlled ground environment that only involves active participants
Examples of vertical objects may be buildings, trees, masts, wind turbines, or powerlines. A controlled ground area is defined here as an operational area that only involves active participants (if any), and there is a level of assurance that there will be no non-active participants in the area.
The following assumptions have been made in the development of the scenario:
· the drone(s) will not be fitted with a detect and avoid system
· no traffic management system will be in operation
· drone to drone conflicts are not considered
· a minimum of a 1:1 buffer will be applied to the operation; for example, if the RPA is to operate at a height of 120m, the ground risk buffer must be at least 120m
· the applicant will have an emergency response plan (ERP).
The scope of the scenario is as follows:
· no autonomous operations: the remote pilot must always be able to intervene during normal operations
· the remote pilot must only operate one drone at a time
· handover of control of the drone from one pilot to another is permitted
· minimum 5km visibility (forecast)
· drone operation permitted at maximum distance of 80% of proven command-and-control link range.
Applicants must provide an outline of the proposed concept of operations, including:
· the activity(ies) to be conducted
· technical details of the drones to be utilised
· minimum crew composition and qualifications
· details of the operational area including contingency area and 1:1 buffer
· explanations as to how the operational area will be conducted in a controlled ground environment and within 100 ft vertically and 120 m horizontally of a structure
· confirmation that the area is a controlled ground area
· confirmation that the maximum aircraft characteristic dimension is less than eight metres, and the typical kinetic energy of the aircraft is <1080 kJ
· confirmation that the flight route is within 120 m horizontally and 100 ft vertically of a structure unless operating VLOS for this portion.
· confirmation that that the applicant has an applicable emergency response plan in place.
Applicants must also submit a geographic data file including:
· flight heights
· flight operational volume
· ground risk buffer (if required)
· identification of any critical infrastructure or sensitive areas
If any adjacent areas (2 nautical miles around the 1:1 buffer boundary) contain any airspace, danger areas or restricted areas that may support increased levels of aircraft activity or air traffic using this airspace, then further restrictions apply.
In addition, to ensure a safe recovery from a technical issue involving the drone, or from any external system supporting the operation, applicants should assess and describe the effects of the following probable failures:
· ability of the drone to continue to fly or make a safe landing with at least one motor inoperative (i.e., the done remains controllable)
· intermittent or degraded command and control link particularly at the maximum operating range and/or around vertical obstacles
· response and crew procedures in the event of a permanent loss of the command-and- control link
· total or partial failure of the remote pilot station affecting systems such as video feeds, internet, manual control interfaces etc. caused by software, hardware, or power failures
· navigation system failures, including loss of GPS, sensors or video feeds, that may result in reducing navigation accuracy
· flight planning failures that could result in a loss of containment e.g., incorrect setting of waypoints or return to home function.
The result must be that no probable failure of the drone or any external system supporting the operation will lead to operation outside of the operational area and 1:1 buffer, and a fatality will not occur from any probable failure of the drone or any external system supporting the operation.
AU-STS 2: BVLOS near a vertical object over a sparsely populated ground environment
The same assumptions as those made in AU-STS 1 have also been made in the development of this scenario. The scope of the scenario is the same as well.
A sparsely populated area is defined here as an area with an average population density of
<10 persons/km2, and with no towns or settlements of >100 dwellings. Applicants must demonstrate by on-site survey and/or analysis of imagery that an average population density of <10 persons/km2 exists within the proposed operational volume during the proposed times/days of operation.
Applicants must again provide an outline of the proposed concept of operations, including the same details as those required by AU-STS 1, with the following additional details:
· an average population density of <10 persons/km2 exists within the proposed operational volume during the proposed times of operation, as demonstrated by on-site survey and/or analysis of imagery
· how overflight of identified dwellings is avoided
· identification of any critical infrastructure or sensitive areas
· how overflight of roads is avoided
· if any overflight of roads are proposed, how this would be performed to meet an acceptable level of safety
· confirmation that the maximum aircraft characteristic dimension is less than three metres, and the typical kinetic energy of the aircraft is <34 kJ.
Applicants must also submit an operations manual for their remote pilots, containing the following (as a minimum):
· theoretical training syllabus
· mission planning syllabus
· practical training syllabus
· BVLOS check flight profile and assessment criteria
· approved BVLOS trainers’ qualifications and experience requirements
· internal training syllabus for BVLOS trainers
· how the remote crew can declare themselves fit to operate before conducting any operation
· how the remote crew is assessed as current and competent
· an up-to-date list of remote crew members authorised to carry out BVLOS operations.
The remaining restrictions are consistent with those for AU-STS 1.
AU-STS 4: BVLOS in a remote area within 3 nautical miles of a registered or certified non-controlled aerodrome, including a helicopter landing site
The assumptions, scope, and basic restrictions for this scenario are again consistent with those for AU-STS1 and 2, with additional restrictions relating to air risk mitigation.
This standard scenario does not consider drone operations to or from the aerodrome, or drone operations over the movement area of an aerodrome. Applicants should consult and utilise the stakeholder engagement process outlined here to identify aerodrome traffic patterns and other considerations. The outcome of this step is to provide an analysis of the air operations taking place to, from, and in the vicinity of the aerodrome. The applicant must provide sufficient explanations as to how the flight will remain clear of approach and departure paths from the aerodrome.
Applicants should also consider if any of the following or combination of the following mitigations can be used to lower the air risk:
Restriction by chronology:
· Can the airfield be closed for the period of the planned operation?
· Can the operation take place at night?
Restriction by operation volume/boundary:
· Can the operation be restricted to a shielded operation?
· Can the operation be restricted to atypical airspace?
· Can the operation avoid the approach and departure path?
· Can the operation avoid the visual circuit pattern?
· Can the operation be separated from instrument approach procedures?
· Can the operating height be reduced to minimise the risk to piloted aircraft
Restriction by time of exposure:
· Can the route be planned to reduce the time in the relevant airspace?
· Can sensors or cameras be used to increase the range from the airfield?
*a shielded operation is here defined as a drone operation within a specified distance, typically 120 metres from, a natural or man-made object.
Finally, applicants must document the crew procedures for how they will:
· detect aircraft entering the relevant airspace
· decide the appropriate action to take
· command the drone to complete this action within five seconds
AU-STS 6: BVLOS below 400 feet AGL in remote Australian airspace, that is defined by CASA as locations with very low population density and low risk of aircraft encounters
The assumptions, scope, and basic restrictions are again here consistent with those for
AU-STS1 and 2, with some minor additional restrictions.
Applicants must provide an analysis of the airspace for both the operational area and surrounding area must be provided. It will need to include areas that will have higher airspace utilisation and how flight operations will be managed and avoided at that time. Applicants must also include procedures for keeping records of any movement within the vicinity of the approved area. Considerations for areas with higher utilisation should include areas of high aerial work activities e.g., agricultural spraying, air shows, gliding/ballon operations, etc.
Finally, although not required as part of this standard scenario, the applicant is also encouraged to adopt any mechanism that may further reduce the risk of a breakdown of safe operation, such as:
· electronic visibility (i.e., ADS-B, FLARM, transponder)
· high visibility paint.
AU-STS 7: BVLOS above 400 feet AGL and up to 5000 feet AMSL in remote Australian airspace, that is defined by CASA as locations with very low population density and low risk of aircraft encounters
The assumptions, scope, and restrictions for this scenario are entirely consistent with
Specific Operations Risk Assessment
For operations that don’t meet the characteristics of a standard scenario, a special operations risk assessment (SORA) will be required. A SORA is a detailed operational risk assessment developed by the Joint Authorities for Rulemaking of Unmanned Systems (JARUS), a group of experts from national aviation authorities and regional aviation safety organisations. JARUS recommends technical, safety, and operational requirements to safely integrate unmanned aircraft systems into aviation.
The full JARUS SORA guidelines can be viewed here. For those interested in finding out more about the SORA application process, this will be covered in more detail in our next article!