Narrative:

One of my flights was dispatched using exemption 3585 due to a destination tempo of 1/4 SM. During a conversation with the chief pilot regarding another flight; it was agreed that the operations supported our use of the exemption which states: '[at] the destination airport; the taf weather conditions shall be not less than 1/2 SM of the lowest weather minimum visibility value established for the instrument approach procedure expected to be used.' the flight's destination was using ILS runway 4 ([runways] 4 and 31 have 3/4 SM landing minimums; [runways] 22 and 13 have 1/2 SM). The issue is that using runway 13 would have had an 11 KTS tailwind and [runway] 22 had a 17 KTS tailwind. Therefore we could not legally use exemption 3585.by the time I realized this; the flight was airborne. I had them return to their departure airport since it was not legal to dispatch.there were too few dispatchers for the weather conditions this evening and that took away from my duties. More dispatchers should have been asked to come in during period of high workload.

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Original NASA ASRS Text

Title: Two air carrier Dispatchers recalled a previously released flight when they determined their decision to dispatch it to a destination was not authorized under the weather conditions.

Narrative: One of my flights was dispatched using exemption 3585 due to a destination tempo of 1/4 SM. During a conversation with the Chief Pilot regarding another flight; it was agreed that the operations supported our use of the exemption which states: '[At] the destination airport; the TAF weather conditions shall be not less than 1/2 SM of the lowest weather minimum visibility value established for the instrument approach procedure expected to be used.' The flight's destination was using ILS Runway 4 ([Runways] 4 and 31 have 3/4 SM landing minimums; [Runways] 22 and 13 have 1/2 SM). The issue is that using Runway 13 would have had an 11 KTS tailwind and [Runway] 22 had a 17 KTS tailwind. Therefore we could not legally use exemption 3585.By the time I realized this; the flight was airborne. I had them return to their departure airport since it was not legal to dispatch.There were too few dispatchers for the weather conditions this evening and that took away from my duties. More dispatchers should have been asked to come in during period of high workload.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.