ICAO and WMO Compliant AWOS

Airport Weather Advisor™ is an Automated Weather Observing System (AWOS) that is compliant with all ICAO and WMO requirements.

Deployed worldwide for over 25 years.

Mesotech’s Airport Weather Advisor™ AWOS is compliant with all ICAO and WMO meteorological aerodrome standards.

METARs and SPECIs generated by Airport Weather Advisor™ are ICAO/WMO compliant. Report frequency and content can be changed through an easy to use interface. Alternate reporting standards like US FAA, Canada, and US Air Force can be chosen with the flip of a switch.

There are no limitation to the number of airfield stations and sensor configurations Mesotech’s AWOS can support. This includes Runway Visual Range (RVR) using forward scatter visibility sensors.

ICAO and WMO Requirements

The International Civil Aviation Organization (ICAO) and World Meteorological Organization (WMO) work together to formulate a series of regulations for AWOS systems for aviation use. The ICAO establishes the requirements for meteorological services to international aviation while the WMO establishes how to meet these requirements and sets the standards for service delivery

These systems include not only performance requirements for the individual sensors but also placement location recommendations at airports and standardized METAR reporting. Mesotech’s Airport Weather Advisor™ was designed and manufactured to meet or exceed all these requirements.

ICAO Recommendation of Sensor Locations

The ICAO offers detailed instructions and guidelines for selecting locations for meteorological AWOS equipment and sensors at an airport or airfield. They also have strict guidelines for obstacle-free zones where no meteorological equipment is allowed as well. Mesotech performs an on-site survey before any installation process can begin to ensure the AWOS tower and sensors are free of any incursion which may interfere with the meteorological readings.

Runway Visual Range (RVR)

Runway Visual Range (RVR) measure visibility, background luminance, and runway light intensity to the determine the distance a pilot can see down the runway and is critical for determining what the instrument landing system (ILS) minimums are for landing categories. Runway visual range is measured with Mesotech’s forward-scatter visibility sensors, which provide better accuracy than the older transmissometer technology.

Transmissometer technology accuracy diminishes after 10,000 meters and at higher visibilities forward-scatter visibility sensor technology are more accurate. Forward scatter sensor also enables auto-alignment and auto-calibration which transmissometers do not offer.

Meteorological Requirements from the WMO

Mesotech’s AWOS are compliant with all WMO sensor recommendations for temperature, humidity, dewpoint, wind speed and direction, precipitation, cloud height, and visibility.

ICAO Precision Approach Categories and AWOS

The ICAO provides criteria for categories of instrument landing systems allowing pilots to land aircraft at night or during periods of inclement weather.
Mesotech offers Airport Weather Advisor AWOS systems that support all precision approach categories.

Category I:

Decision height no lower than 200 feet (60 meters) and a runway visual range of no less than 1800 feet (550 meters) or visibility no less than 2600 feet (800 meters)

Category II:

Decision height lower than 200 feet (60 meters) but not lower than 100 feet (30 meters) and a runway visual range of no less than 1200 feet (350 meters)

Category IIIA:

Decision height lower than 100 feet (30 meters) or no decision height and a runway visual range of no less than 700 feet (200 meters)

Category IIIB:

Decision height lower than 50 feet (15 meters) or no decision height and a runway visual range less than 700 feet (200 meters) but greater than 150 feet (50 meters)

Category IIIC:

No required decision height and no required runways visual range

Airport Weather Advisor™ for ICAO/WMO Applications

The relationship between aviation and meteorology is over a century old. Mesotech’s Automated Weather Observing System Airport Weather Advisor™ helps unite the two providing valuable weather data and meteorological reports to aviation officials and pilots. Airport Weather Advisor is compliant with all ICAO and WMO requirements and can be configured to meet any category of runway. There is no limit to the number of sensors the system can support to ensure that you get the data you need to meet your flight safety requirements.

Mesotech also offers a variety of custom communication options for dissemination of METAR data depending upon your requirements and geographical demands including optical fiber, copper, spread spectrum radio, UHF data radio, and cellular allowing you to customize your system and the ways in which your data is disseminated.


International Civil Aviation Organization (ICAO)

Founded in 1947, the International Civil Aviation Organization (ICAO) is a specialized agency of the United Nations which oversees the principles and techniques of international air navigation. Headquartered in Montreal, Quebec in Canada, the organization is funded and directed by 193 national governments. The ICAO members consist of 192 of the 193 UN members as well as the Cook Islands. Liechtenstein is the only UN member not included among the ICAO members, as it is the only country without an international airport.

The primary function of the ICAO is both to support diplomacy and cooperation of their member states in air transport as well as to research new air transport policy and standardize aviation innovations as directed by governments through the ICAO Assembly. In a world facing immense technological growth and environmental crisis, the ICAO strives for sustainable aviation growth around the globe.

As part of their function, the ICAO Council adopts standards and recommended practices for their members concerning, but not limited to, the following:

• Air navigation and aviation infrastructure
• Flight inspection procedures
• Assists in the facilitation of border-crossing procedures for international civil aviation.
• Defines the protocols used for air accident investigation which are followed by transport safety authorities in all countries who are signatory to the Chicago Convention on International Civil Aviation.
• Provide standardization for raw METAR observational weather data allowing it to be understood throughout most of the world by aircraft pilots and meteorologists.

However, it is important to note that the ICAO is not a global regulator and therefore does not have authority over any national governments. The ICAO standards never supersede the authority of national regulatory requirements and serve merely as a cooperative measure to connect and standardize aviation technology.

World Meteorological Organization (WMO)

Founded in 1950, the World Meteorological Organization (WMO) is a specialized agency of the United Nations with 193 member states and territories which are responsible for promoting international cooperation on atmospheric science, climatology, hydrology, and geophysics. The WMO is governed by the World Meteorological Congress, which meets every four years to set policies and is headquartered in Geneva, Switzerland.

The WMO serves as the United Nations’ authoritative voice on the status and behavior of Earth’s atmosphere, its interaction with the oceans and land, the climate and resulting weather patterns, as well as the distribution of water resources throughout the world. The WMO provides the global framework for international cooperation on the development of meteorology and operational hydrology and plays a leading role in the international efforts to monitor and provide protection for the environment.

The WMO coordinates the worldwide efforts which are required to produce accurate and timely weather forecasts. The Organization also performs weather observations through their group World Weather Watch. The World Weather Watch collects meteorological, climatological, hydrological, and oceanographic data from over 15 satellites, 100 moored buoys, 600 drifting buoys, 3,000 aircraft, 7,300 ships, and roughly 10,000 land-based observation stations.

Accurate and reliable weather data can protect lives and property and promotes the general welfare of global populations. Where aviation is concerned, accurate weather readings are crucial. The WMO produces standards for automatic weather stations and helps oversee the standardization of METAR data.