TV-watching America knows it well as the most vertigo-inducing seat in the house at college football games. But when you first spy the Goodyear blimp aloft, poking hugely along against a clear blue sky, it's as if the Loch Ness Monster had suddenly surfaced in the neighborhood pool.

Washington has been catching this sight since Tuesday afternoon when the airship America - nearly 200 feet long and 60 feet across - set down on a field at Dulles Airport for the first time in six years.

The America is one of four blimps in Goodyear's dirigible fleet. Based six months of the year in Houston, it wanders more than 100,000 miles about the country during the summer keeping the company's name before the public. The America has recently dropped in on Phoenix, Cumberland, Ky. (for the North-South Game), Philadelphia and Pittsburgh.

It takes more than 200,000 cubic feet of helium to keep the blimp aloft plus a staff of five pilots, and 17 ground crewmen, who travel in a bus.

In the summer, wives and children swell the procession in station wagons. A PR person jogs aheads, and when the blimp sets down, there are usually hundreds of locals hoping for a chance at a ride. In vain, for the waiting list is three years old.

An applicant with an inside track, Amy Carter, went up last week. "She had a great time," disclosed a crew member. "She flew the thing."

Flying the America is not easy, though according to pilot Don Woolley, "It's a lot of fun. I enjoy it every time I go up.It's so good you never want to drink or anything. The best part is flying over cities at night - it's very beautiful."

Woolley has been flying blimps for less than a year. Before that he flew hot-air balloons. Perched at the controls of the America, his feet playing on the pedals which direct the ship's rudders, his right arm pulling at the large wooden wheel that effects elevation, Woolley dips the ship's nose and the vast balloon swoops in for a low pass over two men in dingly floating unaware in a pond.

The blimp's crew and their families make up a sort of circus family - a modern, corporate version of the old barnstorming tours in the early days of aviation. Judy Chambers, whose husband has been flying blimps for six years, says the families "all have a special feeling" for the America. "It's something we have pride in."

Aaron Jenkins, a ground crew chief, was married aboard one of the blimps, 1,000 feet above Los Angeles. Since the cabin seats only six, the wedding party was limited to the judge and the pilot, who was best man.

But the crew travels separately from their families, always prepared to board its bus and follow the blimp, for instance, to escape approaching bad weather. The blimp is not hard to keep up with, with a cruising speed of around 35 mph. When it floats in for a landing, crewmen must be on hand to snatch the two long tethers that dangle in flight from its bow, and to hand onto the sides of the "car" itself, so it doesn't bounce aloft again.

The America is scheduled to hang about Washington for the rest of the month, making six or seven flights a day and flashing public service messages from the computerized lights on the balloon at night.

But its arrival here was an uncertain one. This time the blimp beat its groundcrew by two hours, and was unable to land. So, in the words of a spokesman, "She just went back up and flew around for a while, exposing herself - letting everyone know she'd arrived." They knew.