A Calgary man whose unruly behaviour forced a London-to-Calgary flight to land in Edmonton pleaded guilty Thursday to charges of assault, mischief and failing to comply with instructions of a flight crew member.

Justin Frank, 35, was a business class passenger on an Air Canada transatlantic flight in August when he became so abusive, he had to be restrained in his seat with wrist straps and duct tape by crew and passengers.

In Leduc Provincial Court, just south of Edmonton, the Crown prosecutor said Frank had been drinking bourbon during the flight from a one-litre glass bottle. 

Frank started making suggestive and lewd comments to a flight attendant suggesting they "party in a washroom" together, said Ryan Pollard.

At one point when the attendant was bending down, Frank placed his groin two inches from her face while grinding his pelvis.

"She got scared and humiliated," Pollard said.

At another point Frank's arm brushed her breast as he put his arm around and touched her buttocks.

Eventually an off-duty police officer from Scotland tried restraining Frank, who began "punching the TV, cursing, swearing and being belligerent," said Pollard.

It took seven people — three crew members and four passengers — to restrain Frank.

In the courtroom Thursday morning, Frank appeared nervous and remorseful.

Lawyer Rick Muenz said Frank has little memory of what happened.

Frank was mortified after his arrest and spending two nights in jail, said Muenz. 

"The other consequence he's had to face as a result of these charges is the loss of his employment," he told CBC News. "He was fired very shortly thereafter." 

Meunz said he and the Crown agree there is no need for Frank to go to jail. 

"(Sentencing) will likely be some form of probation along with substance abuse counselling," he said. 

"My client is prepared to make full restitution for the extra expenses (of diverting the flight) as well as the damage to the seatback TV unit." 

Whether Frank will be able to fly again remains to be seen, said Muenz.

"One of the greatest concerns for someone like this who has to travel for work is being able to fly," he said.

Frank has been ordered to stay away from alcohol until his sentencing hearing.

Five other charges including sexual assault and consuming alcohol not served on an aircraft were dismissed.

The judge ordered a pre-sentencing report be completed before Frank returns to court on Feb. 4, 2013.