"Arab Republic of Egypt" could be seen clearly now on the side of the airplane as it taxied into the glow from the TV lights and stopped at the long red carpet. The door opened. People began to emerge.

History was about to be made.

And the NBC reporter on the scene knew it.

"I think that's John Chancellor!" he said suddenly, as if he had glimpsed a potentate. We now judge events partly by the celebrity quotient of the reporters covering them, and this event drew the big three of TV news - Chancellor, Barbara Walters and Walter Cronkite, all of them leaving the plane with the press corps prior to the appearance of Egyptian President Anwar Sadat.

When Sadat stepped into the light Saturday, he began a weekend visit that made Jerusalem the news center of the world.

Sadat's unprecedented visit to Israel to speak before the Knesset with Israeli Prime Minister Menachem Begin was another news opportunity made to order for network television, and in fact television networks were being given some credit, and taking it, for making it to order themselves.

Privately, executives at CBS and ABC News were saying their reports of Sadat's offer to visit Israel helped speed the process by which the offer was accepted and the visit became a reality. A skeptic could accept the desirability of these results and still be slightly troubled by darked implications; could network TV, already considered a "fourth branch" of the government in some circles, be turning into a virtual government of its ow, one that helps create the news it reports?

Certainly Walter Cronkite of CBS must have high regard for his own importance at such occasions since he felt free to keep jabbering to viewers even during a moving sequence yesterday in which Sadat placed a wreath on a memorial to Israeli war dead. One wonders if journalists who help bring events about may begin to feel equal in importance to the news itself.

Indeed, there were titanic power struggles going on behind the scenes. ABC's Walters enlisted Begin himself in her effort to get the first interview in history of Begin and Sadat together. Both had already agreed to be interviewed by her separately. But then, ABC says, she talked Begin into talking Sadat into a joint interview. It took up 29 minutes on last night's one-hour late ABC News report.

ABC insiders claim that the mightly Cronkie, confidante of Presidents, was infuriated at this development and insisted to aides of Begin and Sadat that he also be granted a joint interview. And he was. At the end of it, Cronkite reportedly turned to the two world leaders and said, "Okay, now that it's over - did Barbara get anything I didn't get?"

Such shenanigans can't dispel the fact that for television this was another stunning global moment. The technology triumped again, with vivid live transmissions by satellite from the Mideast making the epochal immediate. At times, however, the networks applied so much "coverage" that they nearly smothered the event. Some reporters seemed not to trust the camera's view; they simply talked too much, when pictures could have spoken for themselves.

Competition between the networks was fierce. A CBS spokesman said that Cronkite flew to Cairo Thursday so he could be on board Sadat's plane when it left. Chancellor and Walters reportedly arrived in Tel Aviv later, only to learn they were being scooped. They both flew to Cairo and all three network biggies got interviews with Sadat enroute to Ben Gurion Airport.

Network news competition used to be a two-way tussle between CBS and NBC, but now ABC, under news and sports director Roone Arledge and with Walters as the star performer, has become increasingly aggressive. So when ABC learned yesterday that Cronkite had also secured a joint Sadat-Begin interview, the network decided to go on the air at 5:50 p.m. with a six-minute excerpt from the Walters interview, which was not to air in its entirely until 10:45.

In this way ABC beat CBS and Cronkite onto the air, part of Cronkite's interview was aired during "60 Minutes" at about 7:10 p.m.

President Carter emerged from church yesterday to face a battery of microphones; only ABC aired his remarks live, with a printed legend on screen that said, "ABC News Exclusive" In fact, all three networks had access to the President's remarks but chose to tape them for later use since Sadat was about to step before the Israeli parliament at about the same time.

Arlede runs ABC Sports as well as ABC News and on Saturday it looked clear enough where his priorities and Sadat had just stepped into history at the airport when ABC cut away from its coverage in order to televise a college football game between Ohio State and the University of Michigan. As a result, Walters did not get on the air when Cronkite and Chancellor did, and ABC missed live coverage of Sadat shaking hands with such Israeli leaders as Moshe Dayan and Golda Meir.

ABC cut away repeately from its pre-arrival reports for shots of pre-game activity in Ann Arbor. "We will make sure we don't miss anything in Ann Arbor," reporter Harry Reasoner told viewers. At one point ABC cut directly from Bern Gurion Airport to the football stadium, and the essential message of such a juxtaposition was that the game carried the same news weight as the first meeting in history between the leaders of two nations that have been enemies for 29 years.

Arledge said yesterday that he made the decision to cut away from the Sadat coverage for the football game. 'I think I made the right decision." he said. "We were getting thousands of phone calls from people protesting the fact that the game wasn't on. Sadat was about to go down a long line of dignitaries shaking hands and that looked kind of dull to us. We had another audience we also had to serve."

He said the Ohio-Michigan match set an attendance record of 107,000, a new high for a college game.

Less defensible perhaps was ABC's cross-plugging between the news event and the sports event; the effect was to render them entertainment equals. During the second ABC football telecast of the day, announcer Chris Schenkel elected to wax rhapsodic about his employer. He said of the Sadat arrival. It really was one of the great live coverages (sic), and I'd like to salute ABC News."

ABC's decision to air the Walters interview except at 5:50 yesterday may have been more of a promotional maneuver than a journalistic decision. ABC News told its affiliates earlier yesterday to be sure to plug the 10:45 special with the full-length Walters interview; the except served as a "teaser," like a movie preview.

All three networks reportedly expected the Israeli Information Office to supply them with simultaneous translations of the Sadat and Begin speeches yesterday morning. But this failed to materialize, so each network had to secure its own translator. According to observers who speak either Arabic or Hebrew or both, these translations were less than satisfactory - not exactly misleading, but far from perfect.

It wasn't so much the speeches on Sunday as Sadat's arrival on Saturday that made compelling viewing, however, because the symbolism of his first step onto Israeli soil was so monumental and exhilarating. There was really nothing the TV journalists could do to top it, and in trying, they became annoying.

Perhaps they were as overcome with their own role in making this history as they were impressed by the history itself. Arledge said yesterday that he didn't think the networks consciously served as conduits between Sadat and Begin when the visit was only a hope, but conceded that they became conduits nevertheless.

"It certainly looks as though the media were the main areas of negotiation," he said. "There is no question we were the conduit. But where journalism ends and message-carrying begins is hard to tell."

Sadats first step, then may have been the start of more than one new era, and not all the implications are particularly encouraging.