By Tim Jimenez

PHILADELPHIA (CBS) — A 40-year-old California man is now facing federal charges after authorities say his drunken outbursts caused a flight from Philadelphia to London to turn around last night (see previous story).

Authorities say Robert Coppack, a dual citizen of the US and UK, was drunk and caused a lot of trouble on US Airways Flight 728.

“There’s an allegation in the affidavit that he inappropriately touched a couple of the passengers next to him, and then also one of the females as he was walking back toward the back of the flight,” says prosecutor Sarah Grieb.

In the affidavit, authorities say Coppack told passengers near him he was drinking vodka and that he became “extremely intoxicated and verbally and physically aggressive.”

Flight attendants sent him to the back of the plane, and that’s where federal air marshals met him.  But the incident was not quite over.  “The allegation is that he threatened physical assault on the marshal,” says Grieb.

Coppack is now charged with intimidating and interfering with a flight crew.

Authorities say he could spend up to 20 years behind bars.  He’ll be back in court on Monday for a detention hearing.

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