Flying through Hurricane Gloria almost makes one forget, initially, how much danger is involved, even though first-time barnstormers are greeted with paper bags and warned that someone always gets seriously airsick.

Peering out a window of the P3 Orion turboprop is little help. In the enveloping gloom, only thick clouds are visible. It could be day or night. The four-engine plane cruises for as long as 15 minutes with no unusual turbulence.

Suddenly, the illusion is shattered as a horn sounds and a seat-belt sign flashes. Crew and passengers race for seats, struggling into heavy seat belts and shoulder harnesses as the plane lurches through Gloria's violent winds.

When the warning is not sounded in time, sandwiches fly through the air, coffee cups hit the ceiling and unwary passengers are flung to the side of the plane.

This is a 10-hour flight aboard one of two P3s used by the National Oceanic and Atmospheric Administration. It took off at 12:10 a.m. today to collect data on Gloria for the National Hurricane Center in Coral Gables, Fla.

Inside, the plane is a tangle of electronic equipment that includes computers, printers, radar systems and flashing cathode ray tubes (CRTs).

An intriguing twist is that even though a passenger may have a window seat, he often can learn more about the turbulence outside by asking the CRT in front of him to display data. Enormous amounts of weather data, radar maps and maps of the plane's progress can be summoned at a touch.

Less subtle reminders of potential danger are two orange life rafts, oxygen supplies and automatic flotation devices lining the cabin.

The interior might have been designed by test pilot Chuck Yeager with its olive-drab look, beige tables and a green army blanket used as a tablecloth in the tiny dining area.

The nine-member crew and seven passengers had assembled in a secluded corner of Miami International Airport and soon were flying at 10,000 feet in bright moonlight over the Atlantic.

After the plane passed the Bahamas, there came a slight shudder, darkness and a plunge into Gloria's outer edge, a swirling mass of ice crystals, rain and spectacular cloud formations extending to about 50,000 feet.

As the flight began, there was apprehension because Gloria's highest sustained winds were estimated at 150 mph, making it one of the strongest hurricanes ever recorded. Its strength has since subsided only slightly.

In addition, the other P3 flight sharing the round-the-clock NOAA watch had just landed, reporting major turbulence and lightning, including a bolt that burned a sizable hole in the tail-section radar system.

Regulars aboard the second P3 showed no sign of uneasiness, despite frequent lurches that sent crew members scrambling for seat belts.

Pilot Howard Ticknor, who has flown NOAA hurricane missions for 15 years, after 20 years as an Air Force pilot, is easygoing.

"It's a job. It's exciting. We are an environmental organization. We deliver the goods to the hurricane center," he said.

Noting that the agency has never lost a plane, he recalled returning "with wrinkled wing roots, with popped rivets." Sometimes, he said, "The vibration is such that I can't read the instrument panel. We've had a lot of emergencies, a lot of problems, but never anything I'd consider a close call."

Peter Black, the chief scientist who has flown these missions for 20 years, said, "You have to be a little crazy, but it's fun."

As for the occasional turbulence, Black said he was "not scared, but maybe a little concerned. A hurricane is a pretty awesome example of what Mother Nature can put together."

Other than the food and cups of coffee flying toward the ceiling at times, no major problems were encountered as the P3 penetrated Gloria from many different angles to test intensities of wind and moisture.

The first trip through the eye -- the calm circle at the storm's center -- was so quick that only the brief absence of turbulence made it noticeable.

On another flight through the eye at about 3 a.m., the P3 broke through abruptly out of darkness as a full moon rose eerily over the rim of a thick, angry wall of purple and gray clouds. The flight across the eye, estimated then by crew members at 30 miles in diameter, lasted 10 minutes, and the plane hurtled again into the rattling gloom.

On the plane's belly is a large radar dish, and attached to the wings and nose is a vast array of other instruments, some shaped like huge spears, others like tiny bombs.

The equipment tabulates the wind's speed and direction; the number, size and velocity of raindrops and ice crystals, and the presence of dangerous shearing winds. The data are relayed by satellite to Coral Gables every 30 minutes.

The crews also perform experiments. Today, for example, Black fired probes and buoys toward the ocean to study how the ocean interacts with a hurricane. The probes check characteristics of ocean currents at various depths.

When not chasing hurricanes, NOAA crews are often involved in other environmental tasks, including monitoring movements of polar bears and seals.

Today's crew displayed a grudging sense of humor. Many have flown together on hurricane missions for more than a decade, and several griped about their pay, noting their sometimes hazardous duty.

Another criticized a "Mickey Mouse" decision by the federal government this year to save money by no longer providing sandwiches and soft drinks for the crew during the flight. Now they bring their own.

As the mission continued and Gloria's winds diminished somewhat, Ticknor told the hurricane center by radio that Gloria appeared to be forming a second eye.

None of the scientists aboard could explain immediately the effects of the second eye or the cause of the decreased wind speed.

One scientist, saying he had been looking forward to observing a category 5 hurricane, the strongest of all, said disgustedly that Gloria had turned into a "wimp." Another expressed hope that the wind speed might strengthen after sunrise as the air mass warmed.

The P3 again crossed into the main eye just after dawn but, instead of clear, sunny weather that the scientists hoped for in a perfect hurricane eye, thin clouds obscured the horizon.

Scientist Stan Goldenberg called it "the worst eye I've ever seen" because the birds and debris usually swept up into the eye were blocked from view.

Through breaks in the cloud cover, the ocean was visible, a frenzy of pale-green spray.

Instruments showed that Gloria's winds were about 115 mph, meaning that ground winds might reach more than 135 mph. In addition, radar indicated that the storm cell was expanding as the wind slowed, meaning that larger areas could be affected when Gloria touched land.

About 8 a.m., Ticknor headed the plane away from Gloria. Just short of the Bahamas, the P3 left the storm's bumpy darkness and emerged in bright sunshine over aqua waters and sandy beaches on final approach to Miami International.