AMOSSG/4-SN No. 10

Appendix

APPENDIX

OPERATIONAL EXAMPLE

1.	THE PROBLEM

1.1	Long TAFs are issued every 6 hours : 0600Z, 1200Z, 1800Z et 0000Z. They become valid 6 hours later (from 1200Z to 0600Z, 1800Z to 1200Z, 0000Z to 1800Z and from 0600Z to 0000Z).

1.2	As a consequence there is roughly 24 hours between the time when the TAF is issued (and available for airlines) and the end of the validity period.

1.3	Longest flights are 15h00 long, long haul flights are prepared (flight dispatch) between 5h to 3h15 before the flight departure.

1.4	For example, let's consider a flight departing at 15h00 :

1.5	TAFs must be used 1 hour before, and 1 hour after the time of arrival.

1.6	Between 10h00 and 11h45, when the flight is prepared, TAF05 (issued at 06h00) is the last available. We notice that this TAF is one hour short to cover the arrival period (between 06h00 and 07h00).

1.7	Moreover, flights are getting longer and longer and, as a consequence, more and more flights will face this issue.

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