The Department of Transportation issued a final rule this week mandating that airlines upgrade the lavatories in their single-aisle jetliners so that at least one restroom per plane is large enough for a wheelchair-bound person and an attendant to fit inside at the same time, with the door closed. But the rule gives aircraft manufacturers and airline interior layout designers a decade to figure out how to comply.

“Traveling can be stressful enough without worrying about being able to access a restroom; yet today, millions of wheelchair users are forced to choose between dehydrating themselves before boarding a plane or avoiding air travel altogether,” said U.S. Transportation Secretary Pete Buttigieg. “We are proud to announce this rule that will make airplane bathrooms larger and more accessible, ensuring travelers in wheelchairs are afforded the same access and dignity as the rest of the traveling public.”

The new rule also requires interim wheelchair-accessibility upgrades to at least one lavatory per aircraft as soon as three years from now, and also makes changes to rules relating to on-board wheelchairs and other health issues.

Larger, wheelchair-accessible lavatories.

Congress passed the Air Carrier Access Act (Public Law 99-435) all the way back in 1986. As part of the implementing regulations, DOT in 1990 issued a rule requiring that “Aircraft with more than one aisle in which lavatories are provided shall include at least one accessible lavatory. This lavatory shall permit a qualified handicapped individual to enter, maneuver as necessary to use all lavatory facilities, and leave, by means of the aircraft’s on-board wheelchair.” An Air Transport Association working group then developed standards for compliance.

At the time, limiting the requirement to twin-aisle aircraft was clearly linked to flight duration, on the theory that single-aisle aircraft were only used for short-distance flights, during which most travelers could “hold it” without having to use a lavatory.

However, the new rule makes clear that the 1990 assumption about aircraft type is no longer true: “While accessible lavatories have been required on twin-aisle aircraft for decades, until now, there has been no requirement that airlines provide accessible lavatories on single-aisle aircraft. However, single-aisle aircraft are increasingly used by airlines for long-haul flights because the fuel efficiency and range of the aircraft have improved. The percentage of flights between 1,500 and 3,000 miles flown by single-aisle aircraft increased from less than 40 percent in 1991 to 86 percent in 2021. These flights can last four or more hours.”

Since the assumptions underlying the 1990 twin-aisle-only accessible lav mandate are no longer valid, DOT appointed an accessibility advisory committee in 2016 and started a “negotiated rulemaking” process that lasted from January 2020 to this week.

For lavatory accessibility, the new rule sets forth the following timeframe (the effective date is 60 days after the official publication of the final rule in the Federal Register, which should be any day now).

• Late September 2024 – All requests for new aircraft type certifications for single-aisle passenger airliners with 125 or more seats must include at least one two-person wheelchair-accessible lavatory (see “Late September 2033” below for a description).
• Late September 2026 – All new single-aisle aircraft with 125 or more seats delivered after this date must have at least one lavatory that includes the following features: grab bars, accessible faucets and controls, accessible call buttons and door locks, minimum obstruction to the passage of an on-board wheelchair (OBW), toe clearance, and an available visual barrier for privacy. Existing aircraft do not have to be retrofitted unless the lavatory is being replaced.
• Late September 2033 – All new single-aisle airliners with at least 125 seats ordered after this date must include at least one wheelchair-accessible lavatory large enough for a person with a disability and an attendant, both equivalent in size to a 95th percentile male, to approach, enter, maneuver within as necessary to use all lavatory facilities, and leave, by means of the on-board wheelchair, in a closed space that affords privacy equivalent to that afforded to ambulatory users.
• Late September 2035 – All new single-aisle airliners with at least 125 seats delivered after this date must include at least one of the aforementioned two-person wheelchair-accessible lavatories.

Just how big is a 95th percentile male, you may ask? The new rule does not specify, but the Society of Automotive Engineers says that, in North America, a 95th percentile male is six feet, one-and-one-half inches tall, weighs 225 pounds, and is 20 inches wide at the shoulder. Anyone who has flown on a smaller airliner lately and used the lavatory can easily imagine just how much bigger a lav would have to be to allow two such people to enter and then have one pick up and rotate the other.

So footnote #28 in the final rule is interesting: “Airbus also asked if the Department truly intended to require a space that accommodates both a 95th percentile male passenger and a 95th percentile male attendant at the same time, noting that this ‘worst case scenario’ would be extremely rare. We believe that the rule text is sufficiently clear regarding the intended lavatory size and agree that the scenario described by Airbus is likely to be rare.”

(Also interestingly, according to SeatGuru, United runs an A319 configuration that only has 126 seats. Sacrificing 2 or 3 of those to make a larger lavatory would also push that seat configuration below the level where they would have to install a fully accessible lavatory in the first place.)

Other wheelchair reforms.

The lavatory final rule also incorporates what was originally a separate rulemaking proceeding about on-board wheelchairs (OBW). Starting in late September 2026, airlines must have the following equipment and policies in place: