Was United legally justified when it forcibly dragged a paying passenger off a plane in Chicago on April 9? The airline seems to think so, but it may come down to whether the company complied with government rules on what airlines must do when passengers are involuntarily bumped.

The Transportation Department says airlines must “give all passengers who are bumped involuntarily a written statement describing their rights and explaining how the carrier decides who gets on an oversold flight and who doesn’t.” There’s no evidence United did that. In an internal email published by the Associated Press, United CEO Oscar Munoz said company employees “followed our involuntary denial of boarding process (including offering up to $1,000 in compensation).” But he didn’t say whether those employees followed government rules, including issuing the written statement and giving an explanation for why a given passenger was singled out for bumping.

United’s Rule 25

Rule 25 of United’s “contract of carriage”—which is basically the legal fine print governing passenger flights—contains detailed procedures for how to handle overbooked flights on which passengers need to be bumped, either voluntarily or involuntarily. But there’s no mention of a written statement or an explanation offered to passengers who are bumped against their will. So unless there are other United procedures that aren’t public, the carrier’s official policy seems to exclude what the government requires.

There’s another wrinkle. Rule 25 deals almost entirely with passengers denied boarding—in other words, people who never get on a plane. But in the Chicago incident, the passenger had already boarded when United employees told him he had to get off. Again, unless United has an unpublished policy dealing with this scenario, it’s not addressed in the contract of carriage. So even if United followed its own procedures, it would have violated government rules.

The whole incident seems to have arisen from an unusual situation unanticipated by the airline. United says the flight was already fully boarded when four crew members approached the gate, saying they needed to board the plane to get to Louisville, where the flight was headed, or else a subsequent United departure out of Louisville would have to be canceled. So United made the probably rational decision that it was cheaper to bump four passengers and pay them for their troubles, than to leave the crew members in Chicago and cancel a Louisville departure.

Where it went wrong

This is where the whole thing went wrong. Three passengers chosen by United—how, remains unclear—apparently accepted the airline’s offer and got off the plane. But the fourth passenger United selected didn’t agree to get off, which led to the forced ejection captured on video and now seen by hundreds of millions worldwide.