Bart Jansen

USA TODAY

WASHINGTON – Security officers who dragged a passenger off a United Airlines flight broke from standard procedures and failed to give travelers the respect they deserve, the head of the Chicago Department of Aviation told a Senate panel Thursday.

The department suspended three officers and one supervisor while the city’s inspector general investigates, Ginger Evans, the department’s commissioner, told the Senate Transportation subcommittee on aviation. She apologized, calling the incident "completely unacceptable" and "deeply saddening."

"These actions will not be tolerated," Evans said. “Our policies are clear that force should only be used when absolutely necessary to protect the security and safety of our passengers."

The incident at Chicago's O’Hare International Airport unfolded April 9 when United officials asked airport officers to remove David Dao, a Louisville, Ky., doctor, from United Express flight 3411. The airline bumped Dao and three passengers from the flight to make room for crew members needed in Louisville the next morning. Dao, who suffered a concussion and lost two teeth in the incident, has reached a settlement with the airline.

United CEO Oscar Munoz has apologized several times, most recently at a House hearing Tuesday, for what he called a "mistake of epic proportions." The airline has changed policies, including halting the removal of seated passengers for anything other than safety or security concerns. Crews must check in 60 minutes before departure.

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Evans said the aviation department that oversees O’Hare and Midway airports has taken steps to prevent a similar confrontation. Chicago police and aviation security officers will no longer respond to aircraft for customer service matters, such as overbooking, and aviation security officers will not board a plan except for an immediate medical emergency or physical threat, Evans said. Chicago police will take the lead on disturbances aboard aircraft.

“While we cannot reverse what took place, as a department we are taking action to ensure this never happens again,” Evans said.

Senators on the panel cited other airline problems, such as technology failures that lead to canceled flights and increasingly cramped seating. On Wednesday, American Airlines announced it would reduce the space between seats on some new planes from 31 to 29 inches.

"It’s impossible to ignore the public outcry at recent incidents involving passengers, airline employees, and airport police," said Sen. Roy Blunt, R-Mo., who heads the panel. "This incident was nothing short of disturbing."

Sen. Bill Nelson, D-Fla., said he appreciated the steps United has taken, but that passengers remain upset about how they are treated by airlines.

"I take no pleasure in beating up on the airlines, but in this case it's warranted," Nelson said. “What happened to Dr. Dao was simply unconscionable."

Nelson said Congress may legislate consumer protections as part of Federal Aviation Administration bill to be debated this year.

“I think it may be time for a new passenger bill of rights," said Sen. Maria Cantwell, D-Wash.