Most travelers going through Kennedy International Airport did not really notice that the biggest runway there had been closed for four months of repairs.

For the stressed-out officials overseeing the $376 million project, that may have been the biggest accomplishment of all.

Runway 13R-31L, which reopened Monday, is a picturesque strip that handles a third of the airport’s air traffic. Before the runway shut down in March, pessimists, and even a few newspapers, predicted a chaos of delays and tarmac traffic jams at one of the nation’s busiest hubs.

But airport officials are happy to report that the number of delays during the construction period stayed more or less the same as last year, when about one in every five flights left late.

And save for one scary day in March, when high winds forced the airfield to operate on a single runway, the repairs went off with few problems and little fuss.

“The public cynicism for the capacity of an agency like the Port Authority to build on time, or on budget, is pretty high,” said Christopher O. Ward, the executive director of the authority, which operates the airport. “Failure would have been unacceptable.”

The repairs are expected to reduce delays at the airport and save millions of dollars in long-term maintenance. The lifespan of the runway, the second longest in the country, is expected to be extended by 40 years.

Its newly widened span can now accommodate the most advanced aircraft in the world (including the space shuttle). And its murky asphalt surface has been replaced by bright white concrete, producing a beaming strip along Jamaica Bay.

Just before noon on Monday, a JetBlue airplane taxied to the repaired runway and took off for Tampa, Fla. It was the first aircraft in four months to take flight from the landing strip, which was finished days ahead of schedule.

(Source: NY Times)