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.
Synopsis
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?
Second reporter narrative
On the arrival into MYSM I tried to get weather information from the AWOS on the field. The frequency on the commercial chart was incorrect and was receiving 'Harbor Island'. I kept on checking it but the Captain noticed a different frequency was on the Green Pages. Tried it; nothing. Tried to get weather from NAS radio; nothing. Tried all frequencies multiple times on arrival; nothing. I asked UNICOM as we got closer and he did not seem to understand what an altimeter setting was. We decided to go with Dispatcher's altimeter setting of 30.31. ATC gave a descent to FL030. This did not sound right to me so I checked the Transition Altitude/Level and it was FL180/190 on the commercial chart pages. I figured the Controller was mistaken in his terminology. After I continued to try to get weather but could not; even within 20 miles of the airport. I do not think the AWOS was on; on either frequency. On the ground we finally started getting the AWOS but a lot of the information was missing or incorrect.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.