User Preferred Routes

User Preferred Routing, which has been operational in the South Pacific oceanic airspace for a number of years means airlines can elect to fly optimised routes to achieve better flight efficiency through the benefit of prevailing wind patterns, rather than fly fixed city pair routes.

Fixed routes, whether in the form of permanently defined tracks or flex-tracks (effectively fixed tracks defined every day) are not essential in the Auckland Oceanic FIR (managed by Airways NZ using their Oceanic Control System) and the Oakland FIR (managed by the FAA using their Ocean21 system).  With OCS and Ocean21 and their real time conflict probe, which instantly probes any revision of flight profile, there is no requirement for traffic to maintain fixed routes in order for controllers to be able to identify conflicts.

Pre-departure, using the calculated Cost Index and latest enroute upper air wind and temperature forecast, the Airline's flight planning computer calculates the track between Auckland and San Francisco that will most effectively minimise fuel emissions. This route is known as the User Preferred Route (UPR), the use of which requires Air Traffic Control systems that are able to support aircraft operating outside of predefined airways. Once calculated, the UPR is digitally uplinked to the aircraft, inclusive of the wind and temperature data for loading into the aircraft Flight Management Computer (FMC).

However, UPR require complex separation calculations from the air traffic control provider.  In the UPR environment aircraft flying between the same city pair follow independent random routes and do not normally cross common waypoints as they would in a fixed route structure.

To learn more about New Zealand's Oceanic Control System, click here.

 

User Preferred Routes

Direct route does not take winds into account

 

 

User preferred route allows for prevailing wind patterns