There are more to winds that meets the eye

In November 2017 Australian aviation went through the first major change in forecasting in many years with the introduction of the Graphical Area Forecast (GAF). Previously, weather and winds (below FL140) were contained  in the various textural area forecasts. Various products such as ours would pull out these winds and apply them automatically into your flight plan.

In November 2017 this all changed. Winds aloft information is now presented in another graphical product, the Low Level Grid Point Wind & Temperature (GPWT) forecasts. These divide the country up into 1.5 x 1.5 degree squares and show the winds at 1000,2000,5000,7000,10000 and 14000 ft. Each chart is valid for 3 hours and 8 are produced, covering a 24 hour period.

The higher granularity of both resolution (for example, the old Area 30/32 is now covered by over 22 grid squares) and time (the area forecast winds were valid for 12 hours and each GPWT is valid for 3 hours and there are 8 issued at a time, so we can do accurate planing over a 24 hour period) did away for the need to select subdivisions in a forecast for winds.

GWPT Winds for the ETA at the waypoint

GWPT Winds applied to the flight plan

Forecast validity

Flight plan departure time (within validity of displayed GPWT)

AvPlan EFB and Command Flight Planner are the only products available today which automatically import Low Level GPWT winds and apply them automatically to your flight plan. Our process is fully 4 dimensional in both space, and time – we take into account your departure time, and enroute ETA’s to apply the correct winds from the correct GPWT forecast, automatically.

You can verify this behaviour – just alter your departure time and you will see the forecast winds change based on the winds in the appropriate GPWT forecast.

High level grid winds forecast for 00Z. Altitudes are 5000,10000,FL140, FL180, FL240

Low level grid winds forecast for 00Z. Altitudes are 1000,2000,5000,7000,10000,FL140.

Early on in our development process we chose not to use high level grid winds for flight planning below FL140 (We already had these winds in our system but we weren’t using them, so this would have been an easy option to pursue). As you can see from the images above (which cover the approximate equivalent area and for the same forecast time), the high level grid winds have much lower resolution in both space and vertical extent. There are only two forecast wind points below FL140 for the high level grid winds (for 5000 and 10000ft), versus 6 in the low level winds. You will also notice that the high level grid wind forecasts can be significantly different at the few altitudes that are available (wind direction can be 20-30 degrees different and wind speed 5-15kt different).

Any automated calculations based on high level grid winds for flights below FL140 are going to be significantly different to those based on more accurate low level grid winds. Any pilot using another electronic flight planner is not using the correct winds, especially when flying below 10,000ft, unless these are manually entered during the flight planning process.

AvPlan EFB and Command Flight Planner both automatically switch to using the high level grid winds above FL140 (and these are also 4 dimensional as well).

These product changes for both AvPlan EFB and Command Flight Planner were all tested and implemented as soon as the new weather products came available on the 9th of November 2017. Our team put a great deal of effort into developing the process and testing it to ensure it was available from day one; to ensure our pilots have access to the correct data for mission critical flight planning.