Pan American pilot Truman (Slim) Cummings specializes in taking the fear out of flying.

A veteran of 36 years in the cockpit, the 6-foot-2 Cummings teaches a seven-class course in the subject and has given it in several cities in the last 2 1/2 years.

But on Sunday, while his students were preparing for their concluding classes here in Washington, a horrifying crash occurred on a Canary Islans airport runway, killing 577 passengers and crew members in aviation's worst disaster.

Slim Cummings' wrapup class was scheduled for Monday night at the Dulles Marriott. A "graduation" flight was set for Tuesday morning.

Cummings headed for the surburban motel wondering if he might face a nearly empty classroom. And if not, what would his white-knuckle band say to him, and he to them?

"People called me, these were graduates of the course and others, and said, 'We know it's going to wreck your class,'" said Cummings, who is acquainted with the Pan Am pilot involved in Sunday crash.

"I was prepared to extend sympathy to people in the class. But as they began to come in they came over to me and extended sympathy to me as if I had lost a close relative. One man brought me a bottle of whisky; he said 'You're going to need this tonight.'

"Before that, people came out of a sense of fear. That night they came with a sense of control, sobriety, a sense of facing a tragedy. One man said two people were killed on a highway that he uses, but they didn't stop him from using it.

This was a monumental tragedy. But it didn't keep anybody from coming. There was 100 per cent attendance.

"I think if this had happened early in the course many would have quit. If it happened before the course, many wouldn't have taken it. But we were that far along in the course that they could accept this, an acceptance of the exceptional.

"There were tears in their eyes. And mine. It was a very impressive night."

"I was surprised nobody dropped out of the course," says Cherie Coleman, an aide to Sen. Frank Church. "If it had happened three weeks ago, I never would have completed the course. But now I have an understanding about flying."

Others, who took the course some time ago; also praise Cummings and his approach to a phobia that haunts millions. Most say that Sunday's crash affected them personally in terms of their own flying, but that they would fly again.

John Repp of Kensington, Md., who took a course from Cummings almost a year ago in Philadelphia, confesses that the Canary Island crash "scared" him, but that he will continue to fly.

Martin Jolles of Philadelphia, who describes himself as "not an intrepid flier," says, "I'm of the school of thinking that when you hit the ground you're all right. Obviously that's not true."

Another nervous flier, Maria Oberwager, also of Philadelphia, says Sunday's crash "shook me up a great deal. It set me back a bit, I have to admit that."

Repp, persuaded by a former employer to take the course, says he recently changed jobs to one that will require even more flying, and that he is ready for it. Jolles, who says he always felt "impending doom" in a plane, took his family on a flight to Rome after he had graduated - and after "warming up" with a flight from Philadelphia to New York.

Oberwager seemed more nervous about flying than the other two. She says she keeps track "very closely" when it comes to accidents, but adds, as if trying to be convinced about what statistics verify, "It has to be a safe way to travel." Will she fly again? "I would like to," she says, but didn't commit herself.

Ruth Zuzek of Wilmington, who also took the course last year, says she will not be deterred by the recent disaster. And a classmate, Shirley Kornstein of Huntingdon Valley, Pa., says she was able to get on a flight "five minutes" after hearing about the tragedy Sunday because of Slim Cummings' course.

Cherie Coleman says that during Church's presidential campaign she would take trains a day before the main party moved out. Or she'd get a drink before getting on a plane. Once she said she "faked" illness and stayed in Youngstown, Ohio, instead of moving on to Cleveland. All that's behind her now; she plans to accompany her husband by plane to his new job in Indonesia rather than take a ship.

Not everybody enjoys a successful transition like Coleman's. But Cummings claims a good conversational rate; he says only four from an original 72 dropped out in his recent Washington course.

A former licensed psychologist, Cummings proposed the course to his company, Pan Am, which immediately perceived the benefits. There are an estimated 25 million Americans who fly in fear and another 63 million who have never flown at all. Cummings has merely dented the market with about 800 "graduates."

He says the fear can come in many forms: fear of heights, fear of being closed in. Fear of falling, noise, speed, or death. Or all, or a combination of them.

For a $100 fee, which Cummings says doesn't cover the costs, one can have those fears allayed, beginning with classroom instruction, then a "taxi" session in which the plane does not take off, then the final flight. Although it goes nowhere, ending at the same airport, it apparently has enabled scores to take flights to somewhere they've wanted or needed to go.

Of course, it works to varying degrees.

Jolles, who says he had "all the fears," still "flies under protest," But he can laugh about it now. "The course is spectacular. I don't know if it allays everybody's fears. But Slim explains things you didn't know before, the noises, the motions."

Nevertheless, Jolles says he detected a quick shift in the plane's altitude once during his "graduation" flight and says, "It took me a while to get on that next flight."

Repp says he had to take a flight to get from here to Philadelphia for the course and that Pan Am sent an agent along to sit next to him. On that very flight the pilot aborted the takeoff. "It wasn't a very good start," he says. He stayed on, reluctantly.

"My biggest fear still is that there are so many planes up in the air, so many computer systems, the hectic pace of it all, the human error aspect of it, not enough control. That's why the crash scared me."

But he says he's going to keep flying and that he's being honest when he says, "It doesn't really worry me."

Not nearly as much, anyway, as when he debated whether or not to get off the plane after his abortive takeoff experience. He's 24 years old, and he says he thought then, "I'm too young to say I can't do it. There are too many goals I can't reach if I can't get over it." So he stayed.