That the title of your post is "How do I improve?" earns you an upvote. Also the content.
If it wouldn't cause you problems with your supervisor, you could say something like "Until this process is more accessible, I'll need to guide you. The machine requires precise placement of the feet, so I'm going to guide you to..."
**Anything** to make the process consistent and predictable would be great. I flew a lot before and after the TSA came into being in the U.S. From airport to airport, security procedures are still highly inconsistent. I've generally had better experiences overseas.
In U.S. airports it's hard to predict where to go, what is expected, whether anyone will give instructions, whether those instructions will be relatable, and whether I should ask a question of a security person staring intently at their cell phone. (The airport in Orlando, Florida is especially bad on all these points.) Should I take off my shoes? Leave them on? Am I supposed to unload five pounds of electronics into one bin? Two bins? And will people be annoyed if this takes more than, say, ten seconds?
Something to consider: people don't necessarily want "help" or "assistance." They may need guidance because everyday activities aren't accessible. So for blind and visually impaired (BVI) folks, your work could be construed as making up for a deficiency in the design of airport technology and security processes.
Your organization may label your work as "assistance," but you might want to use different wording to make a connection with a traveler. "Hi, I'm Pat and I'm going to **work with you** to get through this machine."
Consider how to support someone's **independence**. It may take someone extra time, but that person should have that extra time. Fairness means acknowledging problems with accessibility.
Finally, I'd suggest watching one or more videos of blind YouTubers talking about their airport experience. Blind YouTubers are like all YouTubers--some may strike a chord with you, others may annoy you--but some of the more popular videos are worth watching. The video I often recommend for sighted folks is this one from Molly Burke:
$1 I'll mention that I'm sighted but
$1. Mostly I'm fine in airports, but sometimes I'll be confused by building designs that rely on people having good depth perception. For example, if glass doors don't have signs, or if the glass isn't smudged, it could take me longer to realize there's a glass door rather than a doorless entry. Anyone sighted or blind could walk into a glass door or a glass wall, but people with vision impairments are much more likely to do so.