APPLICATION OF AERODROME FORECASTS (TAF AND TREND) TO PRE-FLIGHT PLANNING

(a)         APPLICATION OF INITIAL PART OF TAF

(1)         Application period: from the start of the TAF validity period to the time of applicability of the first subsequent ‘FM…*’ or ‘BECMG’, or if no ‘FM…’ or ‘BECMG’ is given, to the end of the validity period of the TAF.

(2)         Application of forecast: the forecast of the prevailing weather conditions in the initial part of the TAF should be fully applied, with the exception of mean wind and gusts that should be applied in accordance with the policy under column ‘BECMG AT and FM…’ in the table below. However, this may be temporarily superseded by a ‘TEMPO’ or ‘PROB**’, if applicable according to the table below.

(b)        APPLICATION OF FORECAST FOLLOWING CHANGE INDICATION IN THE TAF AND TREND

TAF or TREND for

AERODROME PLANNED AS:

FM… (alone) and BECMG AT:

BECMG (alone), BECMG FM, BECMG TL, BECMG FM… TL, in case of:

TEMPO (alone), TEMPO FM, TEMPO FM… TL, PROB 30/40 (alone)

PROB TEMPO

Deterioration and improvement

Deterioration

Improvement

Deterioration

Improvement

Deterioration and improvement

Transient/shower conditions

in connection with short‑lived weather phenomena, e.g. thunderstorms, showers

Persistent conditions

in connection with e.g. haze, mist, fog, dust storm/sandstorm, continuous precipitations

In any case

DESTINATION

at ESTIMATED TIME OF ARRIVAL (ETA) ± 1 HR

TAKE-OFF ALTERNATE

at ETA ± 1 HR

DESTINATION ALTERNATE

at ETA ± 1 HR

FUEL ERA

at ETA ± 1 HR

Applicable from the start of change

Mean wind

should be within required limits

Gusts

exceeding crosswind limits should be fully applied

Applicable from the start of change

Mean wind

should be within required limits

Gusts

exceeding crosswind limits should be fully applied

Applicable from the end of change

Mean wind

should be within required limits

Gusts

exceeding crosswind limits should be fully applied

Not applicable

Mean wind and gusts exceeding required limits may be disregarded

Applicable

Should be disregarded

Deterioration may be disregarded.

Improvement should be disregarded including mean wind and gusts.

Mean wind

should be within required limits

Gusts

exceeding crosswind limits should be fully applied

ETOPS ERA

From earliest ETA to ETA + 1 HR

Applicable from the start of
change

Applicable from the start of change

Applicable from the end of change

Applicable if below applicable landing minima

Applicable if below applicable landing minima

Mean wind

should be within required limits

Mean wind

should be within required limits

Mean wind

should be within required limits

Mean wind

should be within required limits

Mean wind

should be within required limits

Gusts exceeding crosswind limits should be fully applied

Gusts exceeding crosswind limits should be fully applied

Gusts exceeding crosswind limits should be fully applied

Gusts exceeding limits crosswind should be fully applied

Gusts exceeding limits crosswind should be fully applied

*            The space following ‘FM’ should always include a time group, e.g. FM1030.

Note 1:             ‘required limits’ are those contained in the OM.

Note 2:             if promulgated aerodrome forecasts do not comply with the provisions of ICAO Annex 3, operators should ensure that guidance on the application of these reports is provided.

Note 3:             for the definitions of the meteorological terms used in this table, see ICAO Annex 3.