NOAA’s Hurricane Hunter aircraft are high-flying meteorological stations that collect data in severe storms. That data improves hurricane track forecasts and hurricane intensity forecasts by as much as 20%. Every time the aircraft fly and the forecast improves, communities are saved significant amounts of money by avoiding unnecessary evacuations, and impacted communities can prepare with as much advance notice as possible.
The right tool for the task
Two types of aircraft make up NOAA’s Hurricane Hunter fleet. The Lockheed WP-3D Orion is a turboprop aircraft that flies into the hurricane’s eye directly through the eyewall. A Gulfstream IV-SP flies above and around the storm. The two platforms are tailored for different purposes. The P-3 gathers atmospheric data inside a hurricane, including wind speed, temperature, pressure and moisture, but also has three onboard radars that can provide a “CAT scan” of a hurricane. Where the P-3s fly around 8,000 feet, the Gulfstream jet flies around 45,000 feet to collect data in the broader environment of a storm, including steering currents, by using its radars and deploying dropsondes.
Because of their different purposes and mission profiles, the aircraft have different requirements. Turbofan engines on the G-IV propel the plane safely and efficiently at high altitudes to sample conditions in the storm environment, but they are unable to fly safely into the moisture-laden air of a hurricane eyewall. The P-3s have turboprop engines, a long-standing, proven technology in one of the world’s riskiest flight environments.
“The biggest reason that we use turboprops is that any other kind of engine would not be able to fly through the moisture in the air in the storm,” said Capt. Nate Kahn, the commanding officer of NOAA’s Aircraft Operations Center. “After 50 years, these aircraft are still the best technology for this purpose.”
Engines and eyewalls
In a jet engine, like those on the Gulfstream IV, air and moisture enter the combustion chamber directly. Jet engines routinely fly safely in rainy conditions, but the intense moisture of a hurricane is enough to essentially drown the engine, causing it to fail. In the P-3’s turboprop engines, even though the propellers are driven by turbines through a set of gears, air intakes remove moisture from the air before it enters the engine.
Unlike jets, turboprops can be throttled faster and slower instantly – by adjusting the pitch of the propeller blades as well as varying the propeller speed. That’s important to maintaining a steady speed relative to the ground while collecting data in an environment with widely changing wind speeds.
NOAA and its predecessor agencies have flown into hurricanes using the P-3, the Lockheed C-130 Hercules, the Douglas DC-6 and the Boeing B-50, all propeller-driven aircraft. The agency awarded a contract in 2024 to build a new NOAA-exclusive variant of the C-130J Super Hercules, which will eventually replace the two P-3s. NOAA also awarded a contract to Gulfstream Aerospace Corporation for two new Gulfstream G550s to replace the Gulfstream IV.