A passenger opened a plane's emergency exit door and walked along the wing.

The aircraft had just landed in Seattle when the woman forced open the mechanisms onboard the Boeing 737 Max 8 without being seen by the cabin crew.

Shocking CCTV footage shows the passenger walking along the wing of the Alaska Airlines jet before calmly sitting down.

Ground staff quickly raised the alarm at the Seattle–Tacoma International Airport. Officials said that flight AS323 had arrived from Milwaukee Mitchell International Airport on Sunday December 22.

Airport spokesman Perry Cooper said that the plane had parked at Gate 9 but a woman who was still on board 'became anxious and opened the emergency exit and climbed onto the wing'.

He added: 'Port of Seattle Fire responded just after 5 p.m. and helped the woman off the wing and on a ramp to the ground.'

The passenger was eventually sent to the hospital for evaluation under the direction of the Port of Seattle crisis team.