Narrative:

On descent into mysm cleared to 3;000 ft. Started down and first officer tried to get AWOS. Wrong frequency. On the commercial green page it is correct. Tried unicom no answer. Got an ACARS with dispatch weather. Altimeter setting 30.31 for mysm. Continued descent. First officer used 118.2 AWOS got part of the weather; altimeter missing. Just before slow level off at 3;000 ATC called asked altitude to verify at FL030. I realized he had meant or said FL030 (which meant use 29.92 even though the commercial approach charts show FL180 as transition altitude). I quickly adjusted altimeter to 29.92 but went slightly low. First officer just got hold of unicom prior to level off and I was putting in 30.01. Could have been much worse. Nowhere on the company pages or any where can you find transition of FL030. The first officer did a great job as he had to get weather from 4 sources to get a full weather report; nau radio; AWOS; unicom and dispatch. Also the time hack on the AWOS did not match actual zulu time. Many questions here. Is the unicom operator an approved weather observer? We need to update and improve the information at mysm. Put a note in the airport information pages [that] fl is the only approved weather from NAS. They said they get the weather from someone at the station. So is the observer at the airport and why is the commercial airport page wrong? Why is the AWOS zulu time off?

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Original NASA ASRS Text

Title: An air carrier Captain reported the AWOS at MYSM is poor; accurate weather is difficult to obtain; and the transition altitude apparently is 3;000 FT but charted as FL180.

Narrative: On descent into MYSM cleared to 3;000 FT. Started down and First Officer tried to get AWOS. Wrong frequency. On the commercial green page it is correct. Tried UNICOM no answer. Got an ACARS with Dispatch weather. Altimeter setting 30.31 for MYSM. Continued descent. First Officer used 118.2 AWOS got part of the weather; altimeter missing. Just before slow level off at 3;000 ATC called asked altitude to verify at FL030. I realized he had meant or said FL030 (which meant use 29.92 even though the commercial approach charts show FL180 as transition altitude). I quickly adjusted altimeter to 29.92 but went slightly low. First Officer just got hold of UNICOM prior to level off and I was putting in 30.01. Could have been much worse. Nowhere on the Company pages or any where can you find transition of FL030. The First Officer did a great job as he had to get weather from 4 sources to get a full weather report; NAU radio; AWOS; UNICOM and Dispatch. Also the time hack on the AWOS did not match actual Zulu time. Many questions here. Is the UNICOM Operator an approved weather observer? We need to update and improve the information at MYSM. Put a note in the airport information pages [that] FL is the only approved weather from NAS. They said they get the weather from someone at the station. So is the observer at the airport and why is the commercial airport page wrong? Why is the AWOS Zulu time off?

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.