Special Use Airspace
Background
Some airspace is designated for particular agencies or use cases, and other aircraft are encouraged (or in some cases, required) to remain clear. These special use airspace blocks are designated as danger areas, restricted areas, and military operating areas. Approval is required to operate in a restricted or military operating area, but not to operate in a danger area.
SUA is displayed on most navigation charts, with more details contained in the ERSA SUA section. They are often established to keep aircraft clear of military areas, hazards to flight, or sensitive facilities. In a number of cases, SUA can be temporarily activated, so has little relevance to VATSIM operations. However, pilots may wish to observe the flight planning and navigation requirements associated with them.
Some SUA is used for pre-planned VSOA activities. These airspace blocks are generally released by civil ATS units and restrictions may apply to non-participating aircraft, with associated reroutes and delays. Pilots must comply with any ATC instructions and communicate any operationally-relevant items which may impact their flight around or through the SUA.
Airspace Boundaries
The boundary between two classes of airspace takes the form of the least restrictive class.
Example
A restricted area with a vertical definition of SFC-A085 may be overflown at A085, as the aircraft will be deemed to be in the least restrictive class of airspace at that level.
Danger Areas
Danger areas are established to discourage pilots from transiting a hazardous area. Approval is not required to enter, however pilots should be aware of the risk in doing so. They are labelled with the D prefix (e.g. D556B, which makes up part of the western Sydney training area).
Pilots should generally plan to avoid danger areas but may transit through them if required. Pilots planning to conduct certain operations should determine whether a designated airspace block is available for that purpose, particularly for flight training or aerobatic flight. Most major terminal areas include designated training areas which may be labelled as danger areas.
Restricted Areas
Restricted areas are established to restrict the passage of aircraft through hazardous or sensitive areas. They are labelled with the R prefix (e.g. R405A, which makes up part of the busy airspace over Sydney Harbour). Approval is required to enter. Pilots who do not have approval to enter a restricted area must remain either laterally or vertically clear.
Restricted airspace is classified based on three levels of severity, which impact the flight planning requirements surrounding them. The classification of each restricted area can be found in the ERSA SUA section.
| Classification | Flight Planning Requirements |
|---|---|
| RA1 | Pilots may flight plan through the restricted area and under normal circumstances expect a clearance from ATC |
| RA2 | Pilots must not flight plan through the restricted area unless on a route specified in the ERSA Flight Plan Route (FPR) section |
| RA3 | Pilots must not flight plan through the restricted area and clearance will not be available |
Military Operating Areas
Military operating areas are a subset of danger areas which are established to facilitate a range of military operations. They are labelled with the M prefix (e.g. M550, which makes up part of the military airspace offshore from YWLM). Inside Australian territory, approval is required to enter an MOA.
On VATSIM, MOAs are generally assumed to be deactivated unless being actively used for a military exercise or other purpose. ATC (when online) will generally try to reroute civil aircraft around these activities or will otherwise organise a transit clearance from the station responsible for the airspace.