Recommendation R20020172

Recommendation issued to: AirServices Australia

Recommendation details
Output No: R20020172
Date issued: 20 September 2002
Safety action status:
Background: Why this Recommendation was developed

Output text

Safety Recommendation

The Australian Transport Safety Bureau recommends that Airservices Australia in conjunction with the Civil Aviation Safety Authority and the Bureau of Meteorology develop a standard scale of thunderstorm intensity for use within the aviation industry.

Initial response
Date issued: 04 February 2003
Response from: AirServices Australia
Action status: Closed - Accepted
Response text:

Airservices Australia supports the BoM argument against the recommendation, namely:

"In some countries a single scale of thunderstorm intensity is used in severe weather warnings to the general public. There is no agreement currently, however, that it is appropriate to use such a scale in aviation forecasts and warnings. There is good reason for the reluctance to introduce such a scale. Among of the most significant hazards for aviation associated with thunderstorms are microbursts.

There is, however, no correlation between microburst intensity and the intensity of the thunderstorm with which it is associated. An intense microburst may develop from a weak storm and there may only be a weak down draft from an intense thunderstorm. Ascribing an intensity scale to a thunderstorm would not only not convey any useful information to the aviation community, but could even be counterproductive in the sense that it could lead pilots to believe that there is less danger in flying into a thunderstorm that has a low intensity than one with a high intensity, when this is not the case.

It should be noted also that existing aviation forecasts, the Terminal Aerodrome Forecasts and Trend Type Forecasts, already allow for a description of the expected severity of the individual elements of a thunderstorm - the strength of wind gusts, the intensity of rain, the presence of hail etc, and the associated reductions in cloud ceiling and visibility."

Last update 03 April 2012