View Full Version : A wild and bumpy ride into the eye of Hurricane Isabel

09-20-03, 04:58 AM
September 19, 2003

A wild and bumpy ride into the eye of Hurricane Isabel

By Christopher Munsey
Times staff writer

When the “fasten seatbelt” sign flashes aboard a National Oceanic and Atmospheric Administration hurricane hunter, it’s time to hurry to your seat and slap a thickly-webbed, steel-buckled belt across your lap. Anyone not used to the disorienting motion quickly starts to fall ill as the plane drops, lurches and slides — all at the same time.
Aboard the aircraft, the noise is all encompassing, from the thrumming roar of the four turboprop engines to the whistling rush of air conditioning keeping the banks of electronic weather-measuring equipment cool. Out the side, rivulets of rain slide across a porthole’s glass. The port wing gently bounces up and down, like someone lightly bouncing the handle of a flat steel-bladed saw.

The best place to sit is a narrow ledge in the cockpit, where looking forward into the clouds gives some perspective and relief from the feeling that you’re flying inside a clothes dryer. The hurricane isn’t nearly as dark as a first-timer might expect. Sometimes the gray clouds seem to almost shine — bright enough to make us cover the portholes to eliminate glare.

The aircraft is packed with monitoring equipment and 19 crewmembers. As we cross through the hurricane’s more intense winds, the bank of electronic gear mounted atop horizontal steel cables shimmies like an old washing machine trying to break free.

Cmdr. Phil Kennedy of the NOAA Corps and his crew of pilots, aircrew and scientists are tired; the Sept. 18 flight is their fifth this week into the eye of Hurricane Isabel. But it’s also likely to be their last, as the Category 2 storm sweeps into North Carolina and Virginia. Just days before, Isabel was classified as a Category 5 storm, the strongest there is. A wind gust of 205 knots (almost 236 mph), one of the highest wind speeds ever recorded, was measured by a sensor dropped during an earlier NOAA flight. But on this trip, the top recorded wind speed would be only 95 knots as the storm crossed the coastline and headed inland.

“Tired? Oh yeah, it’s very exhausting,” said crewman Mark Rogers. “After a while, the days start blending together. There’s something about getting bounced around like that that’s very tiring.”

Beginning on Sept. 11, while the storm was in the mid-Atlantic, the WP-3D Orion hurricane hunter — nicknamed “Kermit” — and its twin aircraft, “Miss Piggy,” took turns flying into Isabel from St. Croix in the U.S. Virgin Islands. As the storm moved northwest across the ocean, they moved their base of operations to Tampa, Fla., to stay close to the storm.

NOAA’s hurricane hunting planes have two missions: they serve as flying weather stations and they release probes into the heart of the storm.

Instruments aboard the plane constantly record temperature, barometric pressure and humidity. Three different radars supply information about rain and map wind strength.

The aircrew also releases probes, called dropsondes, into the hurricane. About the size of the cardboard tube in a roll of paper towels, a dropsonde is packed with weather-measuring sensors.

The probes are popped into the clouds via an angled pneumatic tube. Each dropsonde deploys a parachute and falls about 3,000 feet per minute to measure temperature, pressure and humidity, radioing the data back to the plane two times per second. The plane then transmits the information via satellite to the National Hurricane Center in Miami, packaged in one-minute updates. All that information helps the center’s forecasters gauge the strength of the hurricane and issue predictions about its expected track in the form of hurricane watches and warnings.

The work is critical to forming accurate forecasts. According to NOAA, evacuating one mile of populated coastline costs an average of $1 million. Improving the accuracy of predicted hurricane tracks could reduce the warning area, saving money and reducing the disruption to coastal dwellers.

Taking off from Tampa into a bright blue sky over the Gulf of Mexico, just after 8 a.m. Sept. 18, Kermit crossed Florida and headed north to enter the storm after about 90 minutes’ flight time.

Aboard the P-3, the pilot, flight engineer and co-pilot sit close together in the cockpit. In the left seat, the pilot concentrates on keeping the plane level. Sitting slightly behind the pilots in the middle, the flight engineer watches the air speed, ready to reach forward to work the throttles to speed up or slow down the aircraft.

The P-3’s ideal speed for safely flying through the hurricane is 220 knots, said Lt. Mike Silah, a pilot, and like many of the crew, a former member of the U.S. Navy.

If the flight engineer has the throttles at maximum power and the plane is slowing down, he signals the pilot, who will edge the nose down into a shallow dive to pick up speed. If he’s at minimum power and the plane is going too fast, another signal prompts the pilot to gently pull the nose up, slowing it down.

Reaching the eye involves punching through the storm’s eyewall, the innermost band of circulation where the hurricane’s winds are the strongest.

To do that, the pilot flies the plane at an angle, slightly sideways to the main flow of the wind. It’s called “crabbing” for the way it resembles the scuttling progress of a crab, said Kennedy, a former Navy P-3 pilot.

Because the hurricane’s winds are so strong, and because the plane is flying in a mass of air rotating counter-clockwise, a pilot who flew straight for the eye would end up curving away from it.

“To go in, crab to the left, to go out, crab to the right,” Kennedy said.

A typical mission involves penetrating the eye wall six or seven times as the aircraft flies a crisscross pattern through the storm, sending out dropsondes along the way.

There’s not much chatter between the flight deck crew, who operate as one. Crewmembers wear thickly padded headphones and communicate with each other through a finger-keyed microphone.

“It’s a constant give and take between the guys up front. We all know what to expect out of each other,” Silah said. To qualify as a hurricane aircraft commander, Silah will need to reach 2,800 flight hours and handle one of the two pilot positions for 50 storm penetrations.

The flight director and navigator, sitting at the first stations on the port and starboard sides of the aircraft, also have key roles.

The flight director is a meteorologist, and uses radar information to seek out the less intense areas of the hurricane. The navigator works out the best track for the pilots to fly, and keeps in touch with air traffic controllers.

The flight director also serves as a liaison between the scientific researchers who come aboard, and the flight crew flying the plane.

“Our job is to get the scientists as much as they want while keeping anything bad from happening,” said Paul Flaherty, the day’s flight director.

The aircraft flies at 7,000 feet, low enough to catch sight of wavetops cresting and smashing into foam on the dark blue ocean down below.

The plane holds together, but for a newcomer, going through the experience without losing your lunch is a tough trick.

Before takeoff, a visitor is ceremoniously handed an air sickness bag, emblazoned with a fresh “NOAA Hurricane Hunters” sticker. Crewmembers keep an informal count of which visitors heave the most, and spoke almost admiringly of a reporter who hurled his way through nine air sickness bags during a recent flight.

The pilots and navigator belong to the NOAA Corps, described as the nation’s eighth — and smallest — uniformed service. The other crewmembers are NOAA civilians, joined by a few university researchers.

A fleet of 13 aircraft and helicopters is maintained by NOAA at MacDill Air Force Base in Tampa. Three of the planes, the P-3s and a Gulfstream IV jet, leapfrog to airfields in the Atlantic, Caribbean and Gulf of Mexico during hurricane season, based on the path of oncoming storms.

Studying hurricanes is just one part of the aircrafts’ mission, which is to study climate worldwide.

In January, Miss Piggy spent a month in Bolivia studying a seasonal air flow that affects the climate of South America. The aircraft then traveled up to the Gulf of Alaska for more studies. In the spring, Kermit flew to the Midwest to study the formation of tornado-spawning thunderstorms.

The P-3s also travel to Hawaii to study winter storms in the Pacific. Other planes in NOAA’s fleet monitor wildlife sanctuaries, study whale migrations and measure snowpack out West before the spring melt.

Back in Tampa, at the end of a nine-and-a-half hour flight, the Kermit crew’s post-mission briefing ended with an award to flight director Tom Shepherd, who reached the 100 eyewall penetration mark. The distinction entitled Shepherd to wear a white and silver patch on his flightsuit.

As a tractor wheeled the plane into the hanger late that afternoon, crewmembers dug into two ice-filled coolers for bottles of beer and a bit of celebration.

Christopher Munsey is a staff writer for Navy Times.