Control of Mini Unmanned Aircraft Systems (MUAS) Airspace


During 2011, 17% of all DESERT HAWK III DASORs related to manned aircraft incursions into airspace allocated to UAS. In the first half of 2012, this figure decreased dramatically to circa 4%. Whilst a considerable improvement, even 4% is too high given that the risk of mid-air collision with a UAS is a risk held at ODH level.

MUAS flying only takes place if the activity is correctly regulated, authorised and controlled. 1st Artillery Brigade therefore puts a great deal of time and effort into planning and executing MUAS flying in order to keep our Aircraft within our allocated airspace, and to reduce the risk of other aircraft entering our allocated airspace.

To conform with General Aviation Policy and to reduce risks to manned aviators the MAA Regulatory Publication Regulatory Article 2320: Role Specific Remotely Piloted Air Systems mandates that:

Aviation Duty Holders and Commanders shall issue detailed orders for operating RPAS and directs that Aviation Duty Holders and Commanders should ensure a level of safety is provided in respect of collision avoidance, equivalent to that provided by the pilot of a manned aircraft. In notified segregated airspace such as a danger area, other operational area, or temporary segregated airspace such equivalence is provided by a “Layered Safety” approach.

To comply with regulations the 1st Artillery Brigade Flying Orders Book explains in detail the principles, procedures and drills to be carried out for the safe planning and conduct of MUAS flying practices, both on operations and under the stricter rules applied in training, by adopting a layered safety system. This article will only review MUAS training activity.

MUAS Airspace
As the acceptable level of risk in training is lower than that tolerated on operations, realistic MUAS training can be difficult to achieve. As a result, MUAS training only takes place in restricted and segregated airspace, as the aircraft are unable to ‘see and avoid’.

UK military training areas have not been developed specifically for the use of MUAS, so an area must be defined to ensure that MUAS can be flown safely. The area in which MUAS is to operate will ALWAYS be agreed with both the air and ground elements of Range Control and any Airspace Control Authority (ACA). The following describes the process and terminology for determining a safe MUAS flying area:

A. Range Danger Area (RDA)
All UAS Operating Areas (UOAs) must be within the RDA as per UK AIP or equivalent of a training area.

B. UAS Operating Area (UOA)
The UOA is the 3-dimensional space within which the Unmanned Aircraft (UA) may fly through and land in the event of a technical malfunction. The UOA will always be within the restricted airspace of the RDA. The UOA is the foundation for all flying boundaries and is to be agreed by Range Control/ACA before continuing with any further planning. The height is variable but is usually between 1,000 and 1,500ft AGL. Once in force, no other aviation is to enter the UOA. The Officer In Charge of the flying Practice (OICP) will post air sentries on the boundary of the UOA to warn of any violation.

C. Safe Flying Area (SFA)
The SFA is the area of airspace within the UOA which UA flying will take place in – every UOA must have a SFA applied within it. Under normal circumstances, no UA is to be commanded to exit the SFA, although in the event of a technical malfunction, it is accepted that a UA may self-exit the SFA to land within the UOA. The top of the SFA will be at least 600ft below the height of the UOA therefore affording at least 500 ft vertical separation to other aviation over-flying the UOA. No Army UAS will be launched in the SFA until good two-way communications is provided between the Aircraft Captain and the appropriate ACA.

Inevitably, in practice it looks slightly different. An example of MUAS airspace areas on SENTA, complete with air sentry locations and the Launch & Recovery site, is shown below.

To better utilise airspace, and replicate more realistically the dynamic procedures used on operations, requires a lot of planning. Although considerable effort is required to train realistically, MUAS pilots are not able to “Train as they fight” – early engagement by both communities is therefore necessary to reduce the operating risk encountered on initial deployment to Theatre. The August 2012 iteration of Ex PASHTUN DAWN has gone some way towards achieving more realistic training by subdividing the UOA into smaller, numbered, segments, which will require close monitoring and refinement.

Keeping Ourselves Safe
All RA personnel operating MUAS, including the posted Air Sentries, are alert to violations of the UOA by other airborne equipment (e.g. military or civilian aircraft, gliders, balloons) and are to report any such violation to the Aircraft Captain who will respond accordingly to reduce the risk of a collision. Co-located safety staff will also inform Range Control (RC) /ACA without delay.

Returning now to the significance of our MUAS aircraft weights. As noted above, mid-air collision is a ODH-level risk, yet airspace incursions into MUAS allocated airspace still occur. Thankfully, to date, there have been no collisions. But just consider for one moment the implications of a collision with a 10kg T-HAWK, or even a 3.5kg DH3…

All of us in the aviation environment have a responsibility to respect allocated airspace, MUAS pilots/operators and manned aircraft crews alike. Let’s work together to keep our 100% safety record.

Tactical UAS
The procedures above are specific to MUAS and will therefore not apply to the WATCHKEEPER TUAS which will be controlled and have airspace allocated in a very similar way to manned aviation on IFR.

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