Boeing engineers think they have a solution for smelly, grimy plane bathrooms: ultraviolet light. The aircraft manufacturer has filed a patent for a self-cleaning lavatory that disinfects all surfaces in three seconds.

Many passengers would welcome more sanitary plane bathrooms, but they may have to wait a while to benefit from Boeing’s technology. The typical domestic plane has three bathrooms — one in first class and two at the rear.

That number hasn’t changed in decades even as airlines cram more rows on to planes and fill an ever-higher percentage of those seats. And with less time on the ground, those bathrooms aren’t always cleaned to the fullest, despite the increased use.

Boeing’s new bathroom design uses ultraviolet light to clean the bathroom between uses.

The Chicago-based company says the system will take three seconds to clean the toilet seat, sink and countertop in an unoccupied lavatory. Boeing plans to use Far UV, which it says is different from the waves used in tanning beds and is not harmful to people.

The design also incorporates a hands-free faucet, soap dispenser, trash flap, toilet lid and seat and a hand dryer to decrease the number of surfaces passengers have to touch. Boeing says it is also working on a hands-free door latch.

Don’t expect to see any of this on planes soon. Boeing says it still needs to study the idea further, including designing a system to lift and close the toilet seat by itself so that all surfaces are exposed during the cleaning cycle.

Once offered to airlines, it could take years for carriers to update their fleet with the new bathrooms.