Incident Description
A passenger attempted to board an airplane via the air stair door. As she raised her foot to step onto the first step, she placed her foot back on the ground and subsequently lost her balance.
Aircraft Step Measurements
Measurements of the step revealed that its height above the ground varied depending on passenger and baggage load. The step height ranged from 10.25 inches to 12.75 inches.
Handrail Configuration
The air stair door was equipped with a single handrail on the right side of the stairs. This handrail did not extend to the bottom step.
Company Procedures
The company station manual required a person to stand by at the bottom of the stairs to assist passengers during deplaning. However, this assistance was not required during passenger boarding.