A federal appeals court Monday found that a new Federal Communications Commission policy penalizing accidentally aired expletives was invalid, saying it was "arbitrary and capricious" and might not survive First Amendment scrutiny.

The 2nd U.S. Circuit Court of Appeals did not, however, outlaw the policy outright. It ruled in favor of a Fox Television-led challenge to the policy and returned the case to the FCC to let the agency try to provide a "reasoned analysis" for its new approach to indecency and profanity.

The broadcasters had asked the appeals court last year to invalidate the FCC's conclusion that profanity-laced broadcasts on four different shows were indecent, even though no fines were issued.

Included in the arguments were references to a January 2003 broadcast of the Golden Globes awards show by NBC when U2 lead singer Bono uttered the phrase "f------ brilliant." A year later, the FCC said the "F-word" in any context "inherently has a sexual connotation" and can be subject to enforcement action.

David Fiske, an FCC spokesman, said the commission was reviewing the decision and "we'll respond as soon as we finish that review."

A spokesman for Fox did not immediately return a phone message for comment.

In a 2-to-1 ruling, the appeals court said it found that the FCC's new policy regarding so-called fleeting expletives "represents a significant departure from positions previously taken by the agency and relied on by the broadcast industry."

The appeals court said agencies are free to revise their rules and policies but it said they must provide a reasoned analysis, something the FCC had failed to do.

In a majority opinion written by Judge Rosemary Pooler, the appeals court said all speech covered by the FCC's indecency policy is fully protected by the First Amendment.

"With that backdrop in mind, we question whether the FCC's indecency test can survive First Amendment scrutiny," the appeals court said. "For instance, we are sympathetic to the Networks' contention that the FCC's indecency test is undefined, indiscernible, inconsistent, and consequently, unconstitutionally vague."

The court said it could understand why the networks argue that the FCC's indecency policy "fails to provide the clarity required by the Constitution, creates an undue chilling effect on free speech and requires broadcasters to 'steer far wider of the unlawful zone."'

"Indeed, we are hard pressed to imagine a regime that is more vague than one that relies entirely on consideration of the otherwise unspecified 'context' of a broadcast indecency," it said.

"It appears that under the FCC's current indecency regime, any and all uses of an expletive is presumptively indecent and profane with the broadcaster then having to demonstrate to the satisfaction of the commission, under an unidentified burden of proof, that the expletives were `integral' to the work.

"In the licensing context, the Supreme Court has cautioned against speech regulations that give too much discretion to government officials," the court said.

The appeals court gave a nod to what it called "today's realities" when it mentioned the ability of parents to limit what their children see with technological tools that recently have been made available.

"The proliferation of satellite and cable television channels -- not to mention internet-based video outlets -- has begun to erode the 'uniqueness' of broadcast media, while at the same time, blocking technologies such as the V-chip have empowered viewers to make their own choices about what they do, and do not, want to see on television," the appeals court wrote.

In a dissent, Judge Pierre Leval said the FCC had given a "sensible, although not necessarily compelling, reason" for its new policy.

He noted that the FCC had concluded that the F-word "is of such graphic explicitness in inevitable reference to sexual activity that absence of repetition does not save it from violating the standard of decency."

Although Fox was the plaintiff in the appeal, representatives of other networks were interested parties and submitted written arguments to the court.