One thing I've wondered about for a while is why when you go to one of the check-in counters at DCA, and give them your luggage to check, they make you take it to an "airside" x-ray checker, instead of placing it on the belt behind the counter, where luggage goes in. I mean, at a great majority of airports I went to in the USA, you just give the person behind the counter your luggage, and they place it on the belt, and it's then scanned and checked by TSA behind the scenes. At DCA, they do it all upfront. So, I'm wondering why they don't have x-ray scanners behind the scenes like at most airports, to make things more convenient for customers (not having to check in, then bring your luggage(s) to the airside x-ray scanners), especially if they have the ability to? When I asked the check-in lady at the counter, she just wrote "911!" - what a detalied answer. Not.

Thanks,

Andrew

A lot of it has to do with airport space. Places like DCA, IAD, SLC, and HNL don't have the space for the machines behind the scenes so they put them in the check-in area.

Stand adjacent to one of the entry doors and estimate the space that exists behind the counters, and note how much of it is filled with other stuff such as curb-side checkin. Then observe the narrow walkway between the counters and the balcony railing.
You will conclude that without a major construction project and/or unacceptable predestrian bottlenecks, it is not possible to install the xray machines behind the counters. Nor is there space to reverse the xray machines so that baggage could flow from counter to xray to down escalator, because there is no room for a buffer inventory of bags.

All this is so because the "new" DCA is crammed into a too-narrow space between the Metro rail line and the runways, all of which are built on reclaimed wetlands and river. The aerial photos in the "historic" terminal make that all too clear.

However, from the xray the luggage goes down two stories to ground level. Why not install the xrays down there? Possible answer: that would be in the sterile area, in which xray cannot be, and the geometry does not work to change it there, either.

Bag room at DCA is very small and narrow. Used to work there for an airline, so I had SIDA access to ramp area

I suspect it is a matter of space.

At CVG, FWIW, baggage is screened in the basement of T3 concourse B by the TSA. Concourse B is a seperate airside facility in the secure area (think of ATL's setup if you have never been to T3 CVG - you take an underground tram as a pax out to B).

First you have the departures level airside - go one level down to ground level and you have the FIS (US Immigrations & Customs) for inbound Intl. Go yet another level down and you have a good sized basement where luggage is screened. O/T: Go 7 levels up and you have the Delta Ramp Tower in the middle which oversees all 32 gates of Concourse B. (Thank you, Delta, for the tour).

It could be done behind the scenes in a "sterile", off-limits area of the airport. At CVG they're building a full inline system in this area under T3 "B" so that most luggage won't even be touched unless it needs an inspection. For now they have to take it off the belt, screen it, and put it back on the belt.

I don't know how much room there is - if any - on the ground level of DCA or if there is a basement further beneath that which could be used to screen luggage inline. I suspect the room doesn't exist, thus the setup in the lobby.