Narrative:

[I] accepted turnover for flight with one of the ETOPS alternates being mdy (midway island). Mdy has NOTAM for ASOS not providing visibility or altimeter setting. Contacted mdy operations last week via e-mail via response; and they had stated that during daylight hours they would provide observations. This e-mail was forward to rest of department for all to benefit. When I looked at e-mail again today; realized that they had also mentioned that their observations would not include altimeter setting. I reviewed the commercial charts for all of the approaches into mdy; and they all require a local altimeter setting or else they are not authorized. At this point; flight had not entered the ETOPS area of operations; and I elected to change his ETOPS alternates. [NOTAM:] mdy service automated weather broadcast system visibility; altitude and density altitude not avbl[I] advised crew that mdy was not a good ETOPS alternate and we would have to drop it. The remaining ETOPS alternates did not cover the area of operations; so changed all of the alternates; resulting in the crew being given rjcc/cdb (cold bay). [I] sent the appropriate amendments to the crew along with weather; notams and a new ETOPS critical fuel summary. Crew accepted the changes and pressed on.

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Original NASA ASRS Text

Title: A Dispatcher dispatched an oceanic flight with MDY as an ETOPS alternate but it was not legal because of inadequate weather information.

Narrative: [I] accepted turnover for flight with one of the ETOPS alternates being MDY (Midway Island). MDY has NOTAM for ASOS not providing visibility or altimeter setting. Contacted MDY Operations last week via e-mail via response; and they had stated that during daylight hours they would provide observations. This e-mail was forward to rest of department for all to benefit. When I looked at e-mail again today; realized that they had also mentioned that their observations would not include altimeter setting. I reviewed the Commercial Charts for all of the approaches into MDY; and they all require a local altimeter setting or else they are not authorized. At this point; flight had not entered the ETOPS area of operations; and I elected to change his ETOPS alternates. [NOTAM:] MDY SVC AUTOMATED WEATHER BROADCAST SYSTEM VIS; ALTITUDE AND DENSITY ALTITUDE NOT AVBL[I] advised crew that MDY was not a good ETOPS alternate and we would have to drop it. The remaining ETOPS alternates did not cover the area of operations; so changed all of the alternates; resulting in the crew being given RJCC/CDB (Cold Bay). [I] sent the appropriate amendments to the crew along with weather; NOTAMs and a new ETOPS critical fuel summary. Crew accepted the changes and pressed on.

Data retrieved from NASA's ASRS site 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.