CAMEX Top Guns

Flying into the largest storms on Earth is all in a day's work for pilots on a NASA mission to explore hurricanes.

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September 27, 2001: It's a rather daunting job description: "Multi-engine aircraft pilot, substantial experience required, must be willing to fly into hurricanes."

But some pilots with NASA's Convection And Moisture Experiment (CAMEX-4) do exactly that. With eyes wide open they deliberately fly over, around, and even into the biggest storms on Earth.

Right: This high-altitude research plane, the ER-2, flies high above hurricanes while a DC-8 aircraft flies through them -- together the two planes provide unique data for Earth science researchers.

These unusual aviators endure the dangers of flying through hurricanes in the hope that scientific data they collect will improve hurricane modeling and prediction, which in turn might help save property and lives. Instruments aboard the planes measure temperature, pressure, humidity, precipitation, wind speed, lightning and ice crystal sizes -- providing scientists with a hard-won view of the inner workings of a hurricane.

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"You pass through this build-up of clouds that literally fills the sky in front of you," said Gordon Fullerton, a highly decorated aviator and former astronaut who pilots a DC-8 aircraft into hurricanes targeted by the CAMEX-4 study.

"Entering the storm, we're faced with rotating bands of thunderstorms as we fly at about 35,000 feet. A hurricane is just a group of thunderstorms circulating around a point called the 'eye.' You can pass through the eye and experience a calm as you observe thunderstorms circling all around you," Fullerton said.

It may be true that the eye of the storm is cloudless and less windy than the rest of the tempest -- but only someone like Fullerton with plenty of experience (and perhaps nerves of steel) could feel calm surrounded by most intense thunderstorms in the whole hurricane. It's a dangerous place to fly an airplane!

How do CAMEX-4 pilots safely navigate these powerful hazards?

Simply looking out the cockpit window is one way. Because a hurricane is a collection of thunderstorms, pilots can often visually spot the stronger storms and simply avoid them. For example, says Fullerton, "If I see a thunderstorm that climbs up to 60,000 ft., I can tell by its thickness and blackness that I don't want to go in there."

Right: This view, looking straight up through the eye of a hurricane, was captured by navigator Scott A. Dommin -- one of the US Air Force's famous "Hurricane Hunters." Visit Dommin's photo gallery for more such spectacular views or HurricaneHunters.com to learn more about the daring pilots who pioneered the dangerous art of flying into great storms.

Clouds can make such visual spotting difficult, however. "If we encounter a lot of cirrus clouds, we're stuck with just the radar," Fullerton said. The DC-8 pilots can direct their Doppler radars up and down the storm scanning for trouble.

"These storms can be very rough," Fullerton said. "We can experience strong turbulence as well as rapid accumulation of ice crystals, something scientists call 'graupel.' And large hailstones can terribly damage the aircraft."

"It's also noisy," he added. "All the precipitation begins pounding on the windshield. It compares with driving your car fast through a heavy thunderstorm, with the difference being we're above 30,000 ft."

Above: Hurricanes form as warm, humid air rises, causing the moisture to condense out, which releases heat into the air and causes it to rise still faster in an accelerating cycle. This forms the tall, billowing thunderstorms and also leaves an area of low pressure near the surface. Surrounding air is drawn toward this low pressure, spiraling in toward the center due to the Coriolis effect. The rising air also creates a high-pressure area at high altitude, which causes an outward spiraling of clouds high above the main storm clouds. Image courtesy NOAA.

The pilots sometimes pass through strong vertical winds that accelerate the plane downward and then upward. These intense gusts can toss the pilots "up against their straps."

"Depending on the level of turbulence, it can be structurally significant to the airplane," said Fullerton, who said the heavier turbulence can surprise even seasoned pilots. "When you reach turbulence and the coffee flies out of your cup.... [well,] that's when we turn the aircraft toward an area where radar indicates the conditions are better."

Encountering a severe storm within a hurricane can be quite an experience!

Right: NASA's DC-8 research airplane sits on the tarmac of the Jacksonville Naval Air Station during CAMEX-4 as a waterspout forms in the distance. Click on the image for a larger version. [more]

While Fullerton's DC-8 ventures into the storm, ER-2 pilots fly high above it -- at the very edge of space! The ER-2, a civilian version of the U-2 military spy plane, soars to 60,000 feet where instruments can record both the height and girth of the storm.

"One of the reasons that the ER-2 is such a unique platform is the instruments are basically the same as on the satellites in outer space," said Jan Nystrom, an ER-2 pilot with Lockheed. Only the ER-2 is much closer to the storm than orbiting satellites. "We are the close-up lens."

The view from the dizzying height of 60,000 ft. is "definitely something you're not used to. We're kind of in the twilight zone there," he laughed. "The sky above you is much darker because we are above about 90 to 95 percent of the Earth's atmosphere."

From their high perch, ER-2 pilots get a different view of the hurricane's eye than the DC-8 crew.

"Depending on how well-defined the eye of the hurricane is, you can sometimes look down all the way through the storm and see blue water," Nystrom said.

Left: NASA's ER-2 research aircraft is an elegant-looking plane, and its resemblance to the famous U-2 is no coincidence -- the ER-2 is a civilian version of the military spy plane. [more]

A single pilot flies the ER-2 aircraft, which is 63 ft. long with a wingspan of 104 ft. These long, thin wings give the plane a maximum altitude of about 65,000 ft., and its light weight enables it to have a range of 3,000 nautical miles (about 3,452 miles or 5,555 km).

"It really amounts to a high-altitude jet glider," said Larry Montoya, mission manager for the ER-2.

All pilots flying the ER-2 missions received previous experience with the aircraft during stints with the military. These aviators are well aware of the dangers involved and actually are outfitted with spacesuits just like the astronauts use.

"The cabin is pressurized to about 28,000 ft.," said Nystrom. "However, if we should lose cabin pressure for any variety of reasons, then the pressure would drop to ambient pressure. If we didn't have that suit to protect us, our blood would boil .... it would be fatal."

The majority of these missions are flown high above the destruction the storm unleashes at ground level, but the storms right around the eye can sometimes extend all the way up to the altitudes where the ER-2 flies. "When we experience moderate to strong turbulence, we tend to get away from that," Nystrom said.

Right: NASA's DC-8 research aircraft may look like a commercial airliner from the outside, but the inside is a different story! The interior of the plane has been converted into a flying laboratory filled with data-gathering scientific equipment. With the lives of the scientists who operate the instruments also at stake, the DC-8 pilots must be extra-cautious. Click on the image for a larger version. Image courtesy NASA's Dryden Flight Research Center.

Mission rules are followed closely, especially regarding turbulence, where pilots are instructed to escape the area before the situation gets out of hand.

"These rules are driven, basically, by the capabilities of the airplane," Montoya said. It's a situation where following the rules is very important! With the proper caution and equipment, these skillful pilots are able to do their seemingly treacherous jobs safely, collecting vital data from inside the largest storms on Earth.

The ongoing Convection And Moisture EXperiment (CAMEX-4) is the fourth in a series of field research investigations sponsored by NASA's Earth Science Enterprise. The mission unites researchers from 10 universities, five NASA centers and the National Oceanic and Atmospheric Administration (NOAA).

CAMEX-4 -- the Convection and Moisture Experiment home page from NASA's Marshall Space Flight Center

Fact Sheets: DC-8 -- ER-2 -- from Dryden Flight Research Center

Hurricanes: how they work and what they do -- background on hurricanes, from NASA's Earth Science Enterprise

Hurricane Hunters -- Daring US Air Force pilots pioneered the dangerous art of flying into great storms.

Hurricanes -- information about hurricanes from NOAA, with lots of links to hurricane resources.

National Hurricane Center -- home page

Airborne science at NASA's Dryden Flight Research Center -- information about the ER-2 and DC-8 research aircraft

What Lies Beneath a Hurricane -- Science@NASA article: Two orbiting NASA satellites are giving scientists an unprecedented view of what goes on beneath the obscuring cloud tops of great swirling storms.

The Last Hurricane -- Science@NASA article: CAMEX-3 team wrapping up campaign with flights into Georges

Hurricane Bonnie Cuts a Towering Figure on Satellite Radar -- Science@NASA article: Satellite radar from CAMEX-3 shows mountainous cloud chimney