Helicopter Emergency Medical Services (HEMS) Tool

Hello Central Southwest Members!

I participated in the Iowa Aviation Conference in Des Moines this week (glad to see and meet some of you there!) and, while there, I learned about the Helicopter Emergency Medical Services (HEMS) tool from the Chief Pilot at Air Methods.

I don’t know about you, but I had never heard of it… and found it to be pretty interesting so I thought I’d share with you. The Helicopter Emergency Medical Services (HEMS) tool is prepared by the Aviation Digital Data Service (ADDS) within the National Center for Atmospheric Research (NCAR) with FAA funding and its website is: http://weather.aero/tools/desktopapps/hemstool.

From that website, you can read that the HEMS tool was “specially designed to meet the needs of low-altitude VFR emergency first responders. The HEMS Tool can overlay multiple fields of interest: ceiling, visibility, flight category, winds, relative humidity, temperature, radar (base and composite reflectivity), AIRMETs and SIGMETs, METARs, TAFs, and PIREPs. All 3D data are interpolated to AGL altitudes and can be sliced horizontally on 500 ft intervals up to 5,000 ft. All data can be animated in time. The tool has high-resolution basemaps, including streets, hospitals, and heliports for the entire United States. More detail is revealed as you zoom in.” Air Methods uses the information on this website/tool to make their “no go” mission decisions. The 3:26 min demo video on the website shows how the tool works. Note you will need JAVA to  launch the tool.

Many times we spend a lot of time below 5,000 feet (especially flying VFR in busy airspace areas where we need to stay below airspace) so this tool can be helpful even for us GA pilots.

We were also told “MEDEVAC” aircraft (those aircraft with a patient on board or when time is critical… think about it as an ambulance with lights and sirens on) use frequency 123.05 as the HEMS frequency for updates. If you fly in an area where there are a lot of MEDEVAC helicopter type operations, it was recommended during the conference that pilots listen in to 123.025 (Helo Air to Air) and 123.05 (Helo Air to Ground) when appropriate through their standby radio (this information was corrected based on member comments to this post). It was explained to us that most EMS helicopters are usually monitoring and talking on at least three radios: 1) the airport’s CTAF or ATC, 2) the HEMS frequency, and 3) the company’s radio to communicate with the medical facilities.

Hope you find this useful.

Safe flying,


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About Yasmina Platt

Yasmina Platt serves as the Aircraft Owners and Pilots Association's Central Southwest Regional Manager covering NM, TX, LA, OK, AR, KS, MO, NE and IA. She resides in Houston, TX and flies a Piper Archer. For regional updates and information, visit http://www.aopa.org/Advocacy/Airports-and-State-Advocacy/Central-Southwest
  • James M. Clark

    You may be interested to know that the HEMS tool has been around for years and is very useful to the EMS aviation community, but was created on a shoestring budget and is currently staffed by just two very dedicated individuals. Another case of the government having a good concept, but not so good execution. This tool needs to be better supported, so as to evolve from a “Beta” status to a fully supported and certified weather tool – we cannot use it for official weather “go” decisions, only “no-go” decisions. By the way, the air-to-air VHF frequency you stated is incorrect – it’s actually 123.025. Also, if you check the AIM, the term “Medevac” (formerly Lifeguard) can be used on any leg where time is critical, including organ transports, moving medical equipment or personnel, and flights to a patient, as well as patient transport legs.

  • Air Methods Pilot

    The VHF Frequency to monitor is actually 123.025 (Helo Air to Air.) The AMC GOM instructs pilots to announce on this frequency in the blind their intentions at 5mi, 3mi, and 1mi from the landing area or helipad where no established communications exists. Some other groups do this as a courtesy/safety practice as well.
    The Frequency 123.05 is Helo Air to Ground and is used at various hospital to notify the security teams or others of an inbound helicopter and ETA.

  • Bryan

    The HEMS tool is a great resource. I am in law enforcement aviation (rotor and fixed) and I use it every day. It gives me low level weather and I can zoom in to my area of operation instead of looking at just regional weather (which I still look at to understand the weather systems around me). Remember, it is still considered ‘experimental’ though its been in service for years. It may not qualify as ‘official weather’ if needed.

    Also, 123.0125 is for all low level helicopter traffic. You can use it to communicate with tour helos, law enforcement, fire, and many others in certain areas. Great post!

  • http://howtoflyahelicopter.com/ems-flight-crew/ Simon

    Have been using the HEMS tools for ages now and until now it has the job quite well.