Candidates for federal office have a legal right of access to the broadcast media when they seek to bring their campaigns to the public through television and radio, the U.S. Court of Appeals held yesterday.

The three-judge panel, in a decision that could open television in particular to more comprehensive discussions of campaign issues, said networks must take a hard look at an individual candidate's request for air time, including campaign strategy, before any decision is made to reject or limit such a request.

While the decision does not give candidates the right to demand broadcast time, it does put a greater burden on networks to justify their decisions in rejecting or limiting candidates' requests, and it upholds the authority of the FCC to review those decisions and to overrule them.

Senior Judge David L. Bazelon, in an opinion for the court, rejected the networks' argument that the guidelines set down by the Federal Communications Commission for such decisions represent an unconstitutional intrusion of government into the editorial process.

Instead, Bazelon said, the FCC has defined its role in such a way as to preserve broadcasters' discretion by confining itself to a determination of whether the networks fully considered and explained their decisions in each candidate's case.

The law, which gives federal candidates a right of access of the airwaves, is a "constitutionally acceptable" balance between "the public's right to be informed about elections and the right of candidates to speak and, on the other hand, the editorial rights of broadcasters," Bazelon said.

The court's decision yesterday affirmed an FCC ruling last November that the three major networks had acted unreasonably when they refused an airtime request from the Carter-Mondale Presidential Committee for a documentary on President Carter's record and administration. Essentially, the three networks said that the committee's request for a 30 minute prime-time program in December "was too much time, too soon in the race" for the presidency, Bazelon said.

The three networks, CBS Inc., American Broadcasting Companies Inc. and the National Broadcasting Company Inc. took the issue to the court of appeals, which agreed to postpone the FCC ruling until it had time to review the case. In the meantime, the Carter-Mondale Committee accepted offers of later broadcast dates from both CBS and ABC.

Bazelon, citing the "fragile rights at stake" at election time, said that despite the change in facts in the Carter case, the confrontation between candidates and the broadcasters was certain to come up again.

He said that the broadcast reform section of the 1971 Federal Election Campaign Act supported the view that candidates for federal office have a right of access to broadcast media. One of the primary purposes of that legislation, Bazelon noted, was "to give candidates for public office greater access to the media so that they may better explain their stand on issues and thereby more fully and completely inform the voters."

In implementing the candidates' right of access to the broadcast media, the FCC set out "reasonable" standards for the networks to use in making decisions on air time, Bazelon said. Those standards, Bazelon said, were drawn up to minimize the government intrusion into broadcasting -- through FCC review -- and to maximize respect for broadcasters' editorial decisions. f

The networks' obligation under those standards is judged in two stages, Bazelon said. First, networks need not grant a time request prior to the start of a campaign -- a date determined by the FCC. Once a campaign has begun, however, candidates' requests must be treated individually, and reasons for denials must be fully articulated, Bazelon said.

"The commission, for its part, will not substitute its judgment for that of the network . . . in handling individual requests," Bazelon said. Rather, the commission must confine itself to determining if the networks have considered all the facts and offered a reasonable explanation for their decision. Bazelon was joined in his opinion by Judge Edward A. Tamm and Chief Judge Howard T. Markey of the U.S. Court of Customs and Patent Appeals, sitting on the case by special designation.

Tamm, in a separate opinion, concurred with Bazelon's ruling while pointing out what he saw as potential dangers and "grave First Amendment concerns" that are raised when a federal agency steps into decide whether the needs of a particular candidate justify a demand for broadcast time.