Weather or Not
By Leah Murphy, FAA Safety Team Representative
Every preflight should include a comprehensive weather check, but for helicopter pilots operating in low-level flight environments, weather planning can look a little different.
One of the greatest risks to helicopter operations is inadvertent flight into instrument meteorological conditions (IMC). Many helicopters are not certified for IMC and lack the instrumentation and stability necessary for safe flight in zero-visibility conditions. Pilots should thoroughly evaluate real-time observations and forecasts to detect potential hazards.
Standard weather products like METARs, TAFs, AIRMETs, and PIREPs can indicate IMC of low ceilings and poor visibility. However, pilots should also recognize less obvious factors that could reduce visibility, even if IMC is not explicitly forecasted. These include showery precipitation, blowing snow, and haze or smoke, all of which can cause temporary IMC that might not otherwise be indicated. Proactively identifying these risks allows pilots to make informed go/no-go decisions and plan safer alternate routes if conditions deteriorate.
A valuable resource for helicopter pilots is weather radar, which provides real-time data on precipitation and storm activity. The Terminal Doppler Weather Radar (TDWR) system, available through the Aviation Weather Center, is a specialized radar system deployed near major airports. It provides high-resolution weather data focused on a local radius, offering critical insights into wind shear, microbursts, and localized precipitation.
Unlike TDWR detecting short-range weather hazards, Next-Generation Radar (NEXRAD) covers a much larger area and provides a broader picture of developing weather trends. While NEXRAD is ideal for long-range flight planning, TDWR is better suited for assessing conditions around departure and destination airports. Using both sources together provides a more complete picture of weather conditions for a planned route.
In 2006, the helicopter emergency medical services (HEMS) weather tool was introduced as an experimental product designed specifically for the helicopter air ambulance industry. Its creation was in response to an unfortunate history of controlled flight into terrain (CFIT) and loss of control (LOC) accidents in helicopter operations. Many air ambulance flights require pilots to accept a flight request within minutes, leaving little time for extensive weather analysis. The HEMS tool was developed to provide quick, easy-to-understand weather data tailored for low-level flights.
Since its inception, the tool has evolved significantly in its presentation, accessibility, and the range of information it provides. Today, it is fully integrated into the Graphical Forecasts for Aviation-Low Altitude (GFA-LA) web-based platform, available through AviationWeather.gov.
As an FAA-approved source of aviation weather information, the HEMS tool is an essential resource for any pilot operating in the low-level flight environment. Those unfamiliar with this tool should take time to explore its features on both desktop and mobile devices to ensure they can use it effectively when needed.
To access the tool:
- Navigate to the Graphical Forecasts for Aviation page at AviationWeather.gov/gfa.
- At the top right, select the helicopter icon to activate the low-altitude mode, which displays weather information up to 5,000 feet.
- Use the tabs and sidebars to customize the displayed information, including ceilings and visibility, winds, icing conditions, and more.
Helicopter pilots should integrate multiple weather sources to build a comprehensive preflight plan.
By thoroughly evaluating weather conditions, understanding radar imagery, and setting conservative flight limits, pilots can reduce the risk of inadvertent IMC, CFIT, and other weather-related hazards.
Leah Murphy is a dual-rated flight instructor and helicopter air ambulance pilot. She is also an FAA Safety Team Representative in Cleveland, Ohio.
