Notices to Airmen contain ASOS system status. Air Carrier and Commercial Operators should refer to applicable parts of the Federal Aviation Regulations and their company Operations Specifications for use of automated weather observations. Pilots need to understand tha t automated and manual weather observations are different and have different operational implications. ASOS and the human observer differ in methods of data collection and interpretation. Although this is a fundamental change, the manual and automated techniques yield similar results within the limits of their respective capabilities.
AUTO indicates a fully automated report.
No human intervention. COR indicates a correction to a previously disseminated report. The wind direction varies from 180 to 240 degrees. Altimeter always prefixed with an A indicating inches of mercury - reported in hundredths of an inch and reported using four digits. Additional information may be added to the weather observation in the form of remarks.