Specifications include, but are not limited to: The following preventive maintenance checks should be accomplished by the owner’s assigned local maintenance technician in accordance with the provider’s FAA approved maintenance manual at tri-annual intervals. These checks are limited to cleaning, inspecting, comparing, preventing deterioration and helping ensure reliable operation. They are not intended to include the equipment calibration tasks found in the initial and annual verification checks. Tri-annual PM is scheduled on a 4 month interval and should be accomplished at the time it is scheduled. The maximum tolerance is ±15 days from the scheduled tri-annual preventive maintenance check. The results of these checks should be recorded in the Facility Maintenance Log. • (1) Visit facility and accomplish a visual inspection to ensure integrity of the AWOS equipment and site location. • (2) Visual check of obstruction lights. • (3) Visually inspect all sensors and AWOS assemblies. Clean all sensors, lenses, and other parts, as needed. • (4) Check all sensors for reasonableness with respect to existing conditions. • (5) Check video display terminal, keyboard, and archiving. • (6) Check system time and reset as needed. • (7) Check AWOS telephone operation. (8) Aurally check AWOS radio transmission. 64 • (9) Make other checks as necessary or requested by the manufacturer or the FAA to ensure continued reliable operation of the specific system equipment involved.