GM1 MET.TR.220(g) Aerodrome forecasts

• ED Decision 2017/001/R found in: ATM/ANS Provision of Services (2017/373) (Mar 2025)

GM1 MET.TR.220(g) Aerodrome forecasts ED Decision 2017/001/R USE OF PROBABILITY INDICATORS (a) A probability of an alternative value or change of less than 30 % should not be considered sufficiently significant to be indicated. (b) A probability of an alternative value or change of 50 % or more should not be considered a probability but, instead, should be indicated, as necessary, by use of the change indicators ‘BECMG’ or ‘TEMPO’ or by subdivision of the validity period using the abbreviation ‘FM’. The probability group should neither be used to qualify the change indicator ‘BECMG’ nor the time indicator ‘FM’. GM1 MET.TR.220(g) Aerodrome forecasts ED Decision 2017/001/R USE OF PROBABILITY INDICATORS (a)       A probability of an alternative value or change of less than 30 % should not be considered sufficiently significant to be indicated. (b)       A probability of an alternative value or change of 50 % or more should not be considered a probability but, instead, should be indicated, as necessary, by use of the change indicators ‘BECMG’ or ‘TEMPO’ or by subdivision of the validity period using the abbreviation ‘FM’. The probability group should neither be used to qualify the change indicator ‘BECMG’ nor the time indicator ‘FM’.