A federal appeals court didn’t give much legroom to the Federal Aviation Administration in a decision Friday related to the size of airline seats.

The U.S. Court of Appeals for the D.C. Circuit ruled the FAA did not provide enough information on why it denied a nonprofit airline consumer group’s request to regulate the size of airline seats. In what Judge Patricia Millett called “the Case of the Incredible Shrinking Airline Seat,” the court said the FAA didn’t show it adequately considered airline seats are shrinking while passengers are growing in size, nor the possible effects the phenomenon has on emergency evacuations.

“In short, when an agency denies a petition for rulemaking, the record can be slim, but it cannot be vacuous,” Millett wrote. “Especially so when, as here, the petition identifies an important issue that falls smack-dab within the agency’s regulatory ambit. While we do not require much of the agency at this juncture, we do require something.”

The group, FlyersRights.Org, asked the FAA via petition in 2015 to issue rules governing the size of airplane seats to ensure passengers could safely evacuate in case of an emergency, regardless of their size.

In denying the petition in 2016, the FAA said the issues didn’t present “an immediate safety or security concern.” So the group asked for the studies the FAA used to make its decision. The FAA cited its own reports on airplane emergencies, but didn’t address the impacts of smaller seat sizes or increased passenger size on the ability to quickly reach emergency exits.

This omission, the court said, caused the FAA’s case to crash and burn.

“Information critically relied upon by the agency that no one can see does not count,” Millett wrote.

In an emailed statement, an FAA spokesman said the agency does consider the distance between one seat and the seat in front of it in testing and assessing evacuations.

“We are studying the ruling carefully and any potential actions we may take to address the Court’s findings,” the spokesman said.

FlyersRights.Org is also worried shrinking seats and limited legroom could cause medical conditions, though the court agreed with the FAA’s assertion that health issues are not under its purview.

Paul Hudson, president of FlyersRights.Org, said the FAA could consider health issues with permission from the Transportation Department. He said the group, represented by Joe Sandler of Sandler Reiff Lamb Rosenstein & Birkenstock, argued the FAA considers safety issues, and that health issues are inherently safety issues.

Still, Hudson said he hopes the agency “will see the light now” and move forward with the rulemaking process.

“The glass may be 75 percent full,” Hudson said. “We’ll just have to see where it goes from here. We’re gratified that the main part of the decision rejected the FAA’s decision to deny our petition for seat and legroom size rulemaking.”