Soon, long tarmac delays will be a thing of the past, but that doesn't mean an end to frustrating waits.

On April 29 -- just in time for the busy summer flying season -- the Department of Transportation (DOT) will impose new rules that require airlines to release passengers from domestic flights after three hours on the tarmac. The rule applies to delays caused by weather, airport congestion and other causes. After two hours, airlines must provide food and water and access to "operable lavatories." They could be fined $27,500 per passenger if they don't comply.

Before a plane has been grounded for three hours, airlines must offer passengers the option to get off the plane, or they could deplane everyone and reschedule or cancel. The Air Transport Association, which represent all major carriers, warns of an increase in flight cancellations and delays.

The ATA's stance could be posturing designed to pressure Congress and the DOT to be lenient on airlines, according to Kate Hanni, founder of flyersrights.org. She predicts few disruptions, saying that airlines will become more efficient. "They make no money if they don't fly," she said.

But the rules could also portend a new kind of unpleasantness at the airport.

"This is a lose-lose situation," said Terry Trippler of rulestoknow.com, a Minneapolis-based travel website. "The airlines will be forced to cancel flights; travelers won't get where they're going," he said.

Because maneuvering an airplane on tight approaches to runways and locating an open gate at the terminal can be tough, Trippler predicts that pilots will need to make the decision to return to the gate shortly after two hours have passed in order to deplane passengers by the three-hour mark.

Crews returned to the airport may be "timed out" if they have exceeded their flight time limitations. Not all airlines have personnel in every city, so new crews may need to be flown in, which could extend a delay.

Getting on another flight may be challenging because airlines have reduced the number of flights and are flying planes with fewer empty seats.

Tips for flying without delays

The best way to avoid a delayed or cancelled flight is to head out in the morning when weather is less volatile. Also, avoid peak travel times, which coincide with morning and afternoon rush hours on the roadways, because an excess of flights during those popular hours can cause runway backups.

It might also be wise to book with an airline that has replacement crews in town; in the Twin Cities that means Delta and Sun Country.

Anyone flying to New York City should avoid John F. Kennedy International Airport, where the longest runway is closed for resurfacing. Delta, American Airlines and JetBlue have asked the DOT for waivers from the new rules at that airport; the DOT has yet to respond.

Travelers should also be aware that the airlines' contracts of carriage do not require them to provide vouchers for meals or hotels.

A Continental Airlines flight that left passengers stranded overnight at the Rochester, Minn., airport in August helped trigger the new rules. "Time and again, people cite that flight when they talk about these new rules," Trippler said.

Kerri Westenberg • 612-673-4282