British Airways' Concorde flight 189, with American television's top three news anchors aboard, turned back to Heathrow Airport yesterday afternoon.

A light on an instrument panel incorrectly indicated a reverse thruster in a jet engine might malfunction.

Dan Rather of "CBS Evening News," Tom Brokaw of "NBC Nightly News" and Peter Jennings of "ABC World News Tonight" were flying to Washington after covering the Reagan-Gorbachev summit meeting in Geneva.

After a wait of two hours in the airport outside London, passengers returned to the same plane and flew on to Dulles, arriving here about 3 p.m., some three hours later than scheduled . . .

That enabled all three anchors to do their regular newscasts before covering the president's address last night before a joint session of Congress . . .

Rather, in Washington, joked about the experience although he admitted that "in the first seconds it was a little spooky. The pilot did a good job reassuring everybody" . . .

Referring to industry jokes about recent CBS News cost-cutting efforts, Rather said, "It is not true that in order to save money I was flown as baggage. It is not true that we had them use regular and not high-octane fuel on the flight. And it is not true that I brought peanut-butter sandwiches aboard for our crew" . . .

More seriously, Rather said, "The British are marvelous. The pilot used the word 'steady' at least twice and he spoke in a very matter-of-fact way" . . .

ABC's Jennings, "who smokes," Rather pointed out, "didn't light a cigarette the whole trip. And when they lowered the landing gear very early while we were still over the Channel David Buksbaum CBS vice president news coverage and operations jumped up like he'd been stuck with a pin" . . .

NBC's Brokaw said after landing at Dulles that "it was no big deal" . . .

He said he, Jennings and Rather were all sitting in the plane "within sight of each other" on the aborted flight . . .

"We hadn't reached supersonic speed yet," Brokaw said, "and by the time the pilot had dumped the fuel over the English Channel, it was probably an hour after we left that we set down again" . . .

He said the three anchors resumed their discussions of summit coverage in Geneva while waiting in the lounge at Heathrow before returning to the plane . . .

"Trust me," said Brokaw, "it was no big deal. There really was no concern felt on the flight" . . .

Jennings, tweaking CBS' economy drive, said, "We all know Rather likes to fly economy. But we discovered he'd bought only one engine on this flight" . . .

"We just sat around the airport talking for a couple of hours. But then we'd been sitting around the airport talking before we left, too. In the final analysis it was just sort of amusing" . . .

Adding a certain piquancy to the episode was a report last weekend that two Concorde flights landing at Heathrow last week were forced to evacuate passengers by inflated chutes because of emergencies involving the landing gear . . .

Jennings said yesterday that ABC News senior vice president Richard Wald had been an evacuee on one of those flights, in which no passengers suffered serious injuries, although some sprained wrists and ankles were reported . . .

Said Jennings: "I guess British Airways has had a tough week" . . .

The original Flight 189 left Heathrow at 1:17 p.m. London time. The second flight left shortly after 4 p.m. . . .

A spokesman for British Airways in London told ABC that a faulty indicator on the instrument panel caused the turnaround and that no engine trouble was found . . . Also in the News

From our One Step Forward, Two Steps Back file: NBC's faltering "The A-Team" has signed Boy George for a February episode in which he promises to sing a couple of numbers . . .

"The A-Team" has slipped from sixth place last season to 17th place so far this fall but showed a revival last week when wrestler Hulk Hogan made an appearance, apparently suggesting the guest star route was the one to take . . .

And still poking around our One Step Forward, Two Steps back file: ABC will bring back "The Fall Guy" -- which did absolutely nothing for the Thursday schedule earlier this fall -- to do absolutely nothing for the Saturday schedule as of Nov. 30, replacing "Hollywood Beat" in the 8 p.m. time slot . . .

"Beat" reportedly will remain in production . . .

The "debut" on ABC of "Dynasty II: The Colbys" on Wednesday night (it will air regularly on Thursdays starting next week) did well in the 12 big Nielsen markets . . . averaging a 24.5 rating and a 39 percent audience share . . .

The "Dynasty" episode that night, leading into the "debut," averaged a 25/37 . . .

In Washington, "Dynasty" did a 26.4/39 while the "Colbys" averaged a 24.5/39 on Channel 7 . . .

Incidentally, the three nights of "Kane & Abel" on CBS averaged a 22.7/33 in the national Nielsen ratings . . . with Part II, on Monday, making the best showing . . .

It is more and more evident that NBC's new magazine show, "American Almanac," will not make an appearance as a weekly show in January after all . . . and that March is a more likely target . . .

NBC News president Larry Grossman said yesterday that "we're looking for a terrific time slot" and that after discussions with NBC Entertainment president Brandon Tartikoff "it will all depend on other program switches" that won't show up until after the first of the year . . .

The one-hour program has made monthly appearances since August on different nights and is due to air Saturday, Nov. 30, at 10 p.m., when it is expected to benefit from the older audiences who have made a success out of "The Golden Girls" at 9 p.m. . . .

Reportedly, Tartikoff will announce the few midseason replacements expected from the number one network in mid-December and the performance of the prime-time schedule thereafter will go far in determining "Almanac's" placement later in the spring . . .

Grossman angrily denied reports that "Almanac" is undergoing a "retooling" but confirmed that executive producer Ed Fouhy "would be comfortable to have more time to work on the program" . . .

Fouhy told AP yesterday that the program could only benefit from a delay. "There would be more time to get more pieces in production. The key to success is to have a lot of choices and I'd like to build up that inventory" . . .

Grossman said there was no indication at the just-completed affiliates board meeting in St. Thomas, Virgin Islands, that the affiliates were balking at including a comparatively low-rated magazine show in the already successful schedule . . . adding that NBC chairman Grant Tinker "had made a point in his opening remarks to the board of his commitment to the program" . . . Moving Right Along

Channel 5 has signed Yolanda Gaskins to serve as cohost, with Joel Loy, of its weeknight "PM Magazine" show . . .

She will replace Marcia Brazda, who has been with the program since August 1983 . . . Brazda was originally scheduled to leave last summer but stayed on while WTTG sought a replacement. Her "farewell" appearance, according to the station, will be Friday, Nov. 29 . . .

Gaskins most recently has been with Black Entertainment Television here, as producer and host of BET's "Front Page." She previously had been writer/host of "Evening Magazine" on WJZ in Baltimore . . .

Gaskins will make her first appearance on Dec. 9 (WTTG is airing "Shogun" through the first week of December) . . .

Another example of Cosby Power: last Thursday, President Reagan delivered an address to the nation regarding his hopes for the upcoming Geneva summit . . .

During the 21-minute speech that started at 8 p.m., NBC viewers waiting to see "The Cosby Show" gave the network a rating of 16.6, compared to a 13.1 for CBS and 9.2 for ABC . . .

And, in case you haven't heard, negotiations between Ted Turner and NBC News over the latter's acquisition of up to 49 percent interest in Cable News Network with the rights to editorial control ended yesterday, the deadline NBC had given Turner . . .

In a brief statement, NBC said "talks have ended between NBC News and Turner Broadcasting Systems Inc. NBC News will continue to explore its own cable news initiative" . . .

NBC has previously announced that if it can get a guarantee of at least 13.5 million cable TV homes by mid-December from major system operators, it plans to launch its own 24-hour cable news operation by mid-1986 . . .