A fired aviation security officer who dragged a passenger off a plane last year at O’Hare Airport has sued the City of Chicago and United Airlines claiming he wasn’t properly trained to handle the incident.

On April 9, 2017, James Long and several other Chicago Department of Aviation police officers boarded United Airlines Flight 3411 and dragged Dr. David Dao down the aisle after he refused to give up his seat to a United crew member who was traveling to Louisville.

Dao, who reached a settlement with United last year for an undisclosed amount of money, was seen bloodied and flailing in video recorded during the incident that quickly went viral.

Long was initially suspended following the incident, and fired on Aug. 8, 2017, according to the suit filed Tuesday in Cook County Circuit Court.

Another officer involved in the incident also was fired, and a third resigned. The final resolution of disciplinary action was included in Inspector General Joe Ferguson’s quarterly report last October.

The lawsuit claims the CDA and Aviation Commissioner Ginger Evans acted negligently by not properly training Long “how to respond to an escalating situation” with a passenger.

Evans sent a series of defamatory tweets in the days following the incident, the suit alleges. She wrongly tweeted on April 11 that Long was no longer a law enforcement officer and claimed in another tweet that the officers’ actions “were completely inappropriate.” Three days later, she tweeted that the agency didn’t arm its security staff “for good reason.”

Evans made similar claims to the press and at official functions, the suit alleges.

The suit holds that Evans’ statements contained “deliberate and intentionally misleading omissions with the direct intention to harm” Long.

In addition, United acted negligently by not foreseeing the consequences of calling the officers to remove an unwilling Dao from the plane, the suit alleges. United also allegedly defamed the former officer by implying that he “sexually harassed or criminally stalked” Evans.

Long has been unemployed since he was fired, according to the suit. As a result, he has allegedly suffered losses in earnings and benefits he would have otherwise received under his employment agreement, as well as emotional injuries.

He is seeking more than $150,000 from the CDA and United for his financial losses and punitive damages, according to the suit.

“We have not been served with this suit and are unable to comment,” according to a statement from United spokeswoman Erin Benson Scharra.

A spokesman for the city’s Law Department didn’t immediately respond to a request for comment.