The US Dept. of Transportation's new airline consumer protection rules took effect this week, the most prominent being the tarmac delay rule which prevents US airlines operating domestic flights from remaining on the tarmac at large and medium hub airports for more than three hours without deplaning passengers. For delays of two hours, airlines must provide food and drinking water as well as maintain "operable" lavatories, and "if necessary," provide medical attention.

“Airline passengers deserve to be treated fairly, and this new rule will require airlines to respect the rights of their customers,” Transportation Secretary Ray LaHood said.

Adopted in response to a series of lengthy delays for passengers onboard grounded aircraft, the rule allows exceptions only for safety or security reasons or if air traffic control deems deplaning to be disruptive to airport operations.  US carriers operating international flights must specify in advance their own time limits for deplaning passengers.

"We expect carriers to take steps to avoid tarmac delays and cancellations by adjusting their schedules and providing timely information to passengers," LaHood said. "A little extra planning will minimize disruptions."

Other provisions prohibit the largest US carriers from scheduling "chronically delayed flights," and requires a designated employee to monitor and respond to customer complaints "in a timely and substantive fashion," as well as to adopt self-audited customer service plans. It prohibits airlines from "retroactively" changing contracts of carriage that could negatively impact already-purchased tickets and will at the end of July require airlines to display flight delay information for each domestic flight on their websites.

The Department plans to propose further rules in the next few months relating to disclosure of baggage and other fees, and full-fare advertising, it said.