Testifying at an inquest into the death of Ashley Smith, Cpl. Stephane Pilon said he had no alternative.
"It's unfortunate that we had to restrain Ms. Smith, but we also had a job to do," Pilon said.
"I would do exactly the same thing today under the same circumstances."
At times Pilon said he felt he had a dire emergency on his hands. At other times, he said he wanted to prevent any escalation of the situation to the point where it would become an emergency.
He said he had been forewarned Smith could be violent. He said he worried about clear-air turbulence, and noted situations in which prisoners had tried to jump from an aircraft.
"We have to take every scenario into consideration," he said.
"Being in an aircraft at 33,000 feet, I could not afford any violent behaviour."
Smith, 19, was being flown in April 2007 from a psychiatric prison in Saskatoon to Montreal aboard the police turbo-prop of which Pilon was pilot in command.
In the video, Smith appears relaxed and compliant at first as she sits in her seat, looking out the window from time to time, but she becomes fidgety, apparently ignoring an order to keep her hands on the seat rests and undoes her seatbelt.
At a given moment, the four correctional officers accompanying her decide she needs to be restrained.
Among other things, they put a spit hood over her head. She starts to protest, apparently soils herself, and the situation becomes unsettling.
They use a "pig chain" as they struggle to secure her hands to her shackles. They put a second spit hood on.
"Let go, you're hurting me," Smith says at several points, her voice thin and girly.
At times, she tries to remove the spit hoods but her resistance appears to be minimal.
Pilon, the pilot in charge, then appears and warns Smith to behave.
"Don't bite me," he says.
"I'm not," Smith responds.
"It'll get worse if you do."
"How can it get worse?"
"I'll duct-tape your face."
Pilon said he had once been bitten by a drug user and, even though Smith was wearing two spit hoods, he worried about communicable diseases.
Under cross-examination from Smith family lawyer Julian Falconer, Pilon said it was his decision to apply duct tape to Smith's wrists.
"We used what we had at our disposal at that moment," Pilon said.
Duct tape, he said, had been used by other airlines to restrain unruly passengers, but admitted he had never done so himself before or since. He also conceded he had not been trained in using duct tape.
More appropriate restraints are now standard, Pilon said.
Falconer said the video shows prison authorities did not have the tools to manage the mentally disturbed teen.
"They trussed her up like an animal," he said during a break in proceedings.
Despite the situation, Smith remained calm through the rest of the flight.
She and the guards banter about her various stays in prison, her family, schooling, her favourite meal, the weather, and other topics. They laugh as they chit-chat, her smile visible through the mesh of the spit hoods.
"I kicked a lot of guards," Smith brags at one point.
"You like your boots? How long does it take to shine them?" she says at another.
Smith's family had long demanded the video be made public, but Correctional Service Canada fought its release every step of the way.
Screening of the video in October following a two-year battle helped break open a legal logjam that had stalled the inquest.
Prime Minister Stephen Harper called CSC's behaviour unacceptable and ordered prison authorities to co-operate with the inquest.
Smith, of Moncton, N.B., was transferred from the Regional Psychiatric Centre in Saskatoon after a supervising guard was charged criminally with assaulting her there.
She choked herself to death at a prison in Kitchener, Ont., in October 2007.
The inquest resumes Monday.