Frequently Asked Questions about AWOS and Airport Weather Advisor®

Airport Weather Advisor® (AWA) Systems and Software

Are Airport Weather Advisor® AWOS FAA certified? 

Yes. Mesotech supplies FAA certified systems for United States domestic airports. Our AWOS A, I, II, III, IIIP, IIIPT, and IV Z systems are all certified.

The list of certified Non-Federal AWOS systems and manufacturers is available here at the FAA website.

Are Airport Weather Advisor® AWOS ICAO compliant?

Yes, Mesotech has designed, manufactured, and installed ICAO compliant AWOS around the world since 1993.

What are the major components of an Airport Weather Advisor® AWOS system?

  • Airport Weather Advisor® aggregates data from an unlimited number of airfield stations with customizable sensor configurations throughout the airport. Critical data like wind speed and direction and visibility may be collected from multiple runway locations.
  • Data is collected by the Data Collection Platform (DCP) at the airfield stations and is transmitted to the Central Processing Station (CPS) located indoors. The CPS processes the data, creates automated reports, and allows for manual report editing.
  • A typical airfield stations includes these components:
          • 30ft tower and mounting pedestals
          • Data Collection Platform (DCP)
          • Sensors
          • UHF or spread spectrum data radio and antenna
  • A typical Central Processing Station includes these components:
  • Desktop or server computer
  • Airport Weather Advisor® Software
  • NOTAM recording hardware
  • VHF Ground to Air transmitter and antenna (UHF for military applications)
  • UHF or spread spectrum data radio and antenna

What communication options are there?

We have a wide range of communication options to fit any location. For unique locations and networks, we develop custom communication solutions. Here are some examples of typical communication options:

  • UHF data radios
  • Spread spectrum data radios
  • Optical Fiber
  • Copper telco lines
  • TCP/IP (WiFi, Ethernet, LAN/WAN, etc.)
  • 4G/5G cellular data

What sensors are included with an AWA system?

This sensor we provide depend on the type of system (FAA, international, military, etc.) and site specific requirements. We tailor sensor selection based on the application.

FAA certified systems have the specific configuration options listed below:

  • AWOS A: Altimeter setting
  • AWOS A/V: Altimeter setting, visibility
  • AWOS I: Altimeter, wind speed/direction, temperature, dew point, and density altitude
    AWOS II: The same as AWOS I plus visibility
    AWOS III: The same as AWOS II plus precipitation accumulation, cloud height, and sky condition
    AWOS III P/T: The same as AWOS III plus present weather and/or thunderstorm detection
    AWOS IV Z: Same as AWOS IIIPT plus freezing rain detection

Where are Airport Weather Advisor® systems installed?

Mesotech's Airport Weather Advisor® systems are installed on every continent, including Antarctica. Below is a list of some recent installations:

  • United States:
  • Alabama: Redstone Arsenal, Lowe AHP, Hanchey AHP, Shell AHP
    Alaska: Fort Wainwright, Bryant AAF
    Arizona: Gila Bend AFAF, Libby AAF, Laguna AAF
    California: Vandenberg AFB, Edwards AFB, Goldstone DSCC, Bicycle Lake AAF, Cameron Park Airport
    Texas: Biggs AAF, Robert Gray AAF, Hood AAF, and Laughlin AFAF
  • Wake and Shemya Islands
    Other USAF locations in LA, TN, MD, VA, MA, WI, WY, MI, HI, and FL
  • International
  • Japan: Camp Zama
    Korea: Osan Air Base, Yongsan Air Base
    Kuwait: Ali Al Salem AB
    Antarctica: Palmer and McMurdo Stations
  • Sierra Leone: Lungi International Airport
  • Canada: Multiple public and private airports
  • Panama: Contadora, Pedasi, Jaque, and Guarare Airports
    Angola: Quatro de Fevereiro International Airport and 10 others

Does Mesotech provide installation services?

Yes, we install AWOS around the world. We work with you to determine the most effective installation plan whether it is complete turnkey or just basic engineering support.

Does Mesotech provide training?

Yes, Mesotech offers operation and maintenance training to airport staff and independent maintainers.

Please contact us for more information.

General AWOS Questions

How do I know I'm buying an FAA certified AWOS?

You should verify that the system you are purchasing is listed on the FAA's List of Certified Non-Federal AWOS Systems and Manufacturers and that the level of system you are purchasing (AWOS III, IIIP, etc.) is certified.

The manufacturer providing the system will be able to provide you with a type-certification letter from the FAA that lists all of the components that make up the type-certified system.

Only systems certified and commissioned at AWOS level III and above may share their data with the FAA and the aviation community using WMSCR.

What specifications should I use when purchasing a non-Federal FAA certified AWOS?

When procuring a non-Federal FAA certified AWOS, it is important to ensure the specifications for the solicitation/bid are not tailored to allow only one manufacturer to participate. A common example is an RFP specifying a proprietary sensor design rather than general performance requirements.  

To encourage fair and open competition, Mesotech has created a set of sample specifications that align directly with the FAA advisory Circular and do not exclude any certified systems/manufacturers.

These specifications are available here.

Does the FAA certify individual AWOS sensors?

No, the FAA does not type-certify individual sensors and does not publish a list of "certified sensors."

Sensors are approved as part of a complete, type-certified system including the data processor, operator terminal, voice subsystem, manuals, and other equipment and documentation.

Refer to FAA Advisory Circular 150/5220-16E, paragraph 2.1.a: "The manufacturer should provide the FAA with the test data and other system documentation to demonstrate that the AWOS system meets the criteria of this AC. Reference paragraph 2.2, Manufacturers Submittals for Type Certification Approval. Upon completion of all the requirements set forth in this AC, the FAA will grant type certification approval to the specific system configuration documented in the request."

What are the maintenance requirements for FAA AWOS?

FAA certified AWOS must be serviced three times per year by a qualified technician with FAA verification authority for the particular system they are servicing.

To obtain verification authority, technicians must hold an FCC General Radio-Telephone Operators' License (GROL), complete an FAA-approved training course or exam, and complete a hands-on performance exam. Refer to the FAA website for details.

Mesotech offers training to airport staff and third party maintainers in order to meet the FAA-approved training requirement.

The specific procedures for maintaining Airport Weather Advisor® systems are included in the system maintenance manual.

How much does an AWOS cost?

AWOS costs vary significantly depending on individual airport requirements, the number and types of sensors, civil works requirements, etc.

Costs can be minimized re-using existing infrastructure (concrete pads, towers, etc.), training local maintainers, starting with fewer sensors and upgrading later, and other strategies depending on the airport.

Your airport may be eligible for federal Airport Improvement Program (AIP) funding that can significantly reduce the cost of your new or replacement AWOS. Click here for more information about AIP and AWOS.

How often do AWOS update?

The voice output sent by VHF transmitter and telephone is updated once per minute.

Are AWOS wind reports true or magnetic?

Wind reports provided over the VHF radio and telephone use magnetic direction.

Does AWOS report lightning?

Not all AWOS detect lightning. The "T" in AWOS IIIPT is for thunderstorm detection. AWOS IIIPT and higher AWOS systems report lightning / thunderstorms.

What does AWOS stand for?

Automated Weather Observing System

What does AWOS IIIP mean?

AWOS IIIP is a specific AWOS configuration. The "IIIP" denotes the types of sensors that are included and what types of data are output.

Below are the AWOS configurations defined by the FAA:

  • AWOS A: Altimeter setting
  • AWOS A/V: Altimeter setting, visibility
  • AWOS I: Altimeter, wind speed/direction, temperature, dew point, and density altitude
    AWOS II: The same as AWOS I plus visibility
    AWOS III: The same as AWOS II plus precipitation accumulation, cloud height, and sky condition
    AWOS III P/T: The same as AWOS III plus present weather and/or thunderstorm detection
    AWOS IV Z: Same as AWOS IIIPT plus freezing rain detection

What is the difference between AWOS / ASOS / ATIS?

AWOS – Automated Weather Observing System

In the US there are federally owned/operated AWOS and non-Federal AWOS that are commercially manufactured. AWOS generates and transmits minute by minute updates of the weather at the airport and reports on a variety of meteorological factors, depending upon the system making the data virtually real-time. AWOS have nine levels of reporting, but most airports will have some variety of AWOS-III. While AWOS reports are automated, they may include human observations when visibilities are reduced, if the AWOS is unmonitored, an “AUTO” tag is included in the textual output.

ASOS – Automated Surface Observing System

ASOS systems are mostly operated and controlled by the NWS, DOD and, occasionally, the FAA. They have a level of reporting comparable to an AWOS-III up to IV Z and offer hourly reports on barometric pressure, wind speed and direction, DA, visibility, sky condition, ceiling height, precipitation, and in some cases thunderstorm and freezing rain detection. ASOS systems are the National Weather Service’s primary climatology network for observing and reporting weather in the United States and may be found in locations other than airports if they serve to improve weather awareness in locations pertinent to the public.

ATIS – Automated Terminal Information Service

An ATIS system provides pilots with essential airport information beyond just weather data. The supplemental information is provided by a human monitoring the system from the tower. You will only see an ATIS system at a towered airport. When the tower shuts down, the ATIS system typically reverts to an ASOS or AWOS system. ATIS reports are published hourly at 55 minutes past the hour, unless the weather is rapidly changing and additional information is deemed necessary. In addition to weather data, the ATIS often provides information about the active runway, runway surface conditions, and other pertinent information such as notices about construction.


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