Dr David Dao, 69, was manhandled off a flight by security staff at Chicago’s O’Hare airport on Sunday after being selected at random to be removed from an overbooked United flight when seats were needed for cabin crew.

Videos have been released showing him being dragged down the aircraft’s aisle and then returning to the aircraft with a bloodied face.

Now Dao’s lawyers have filed an emergency request in a Chicago court to ensure that the airline and airport preserve all video, cockpit voice recordings and other material relating to the incident.

In the court filing, Dao’s lawyer said: “After being duly processed by the ticket agent, checked in by the attendant and seated in his assigned passenger seat, petitioner [Dao] was forcibly dragged and removed from the said aircraft by City employees, sustaining personal injury.”

Meanwhile, United’s embattled chief executive Oscar Munoz has refused to resign over the incident but has apologised.

“The truly horrific event that occurred on this flight has elicited many responses from all of us: outrage, anger, disappointment. I share all of those sentiments, and one above all: my deepest apologies for what happened,” said Munoz in a statement.

“I continue to be disturbed by what happened on this flight and I deeply apologise to the customer forcibly removed and to all the customers aboard. No one should ever be mistreated this way.  

“I want you to know that we take full responsibility and we will work to make it right.”

Munoz has also started a review of how United handles overbooking situations including crew movement and its policies for incentivising volunteers to take another flight. United plans to release details of this review by April 30.

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