Bay Area travelers should anticipate new headaches at San Francisco International Airport this summer, when runway construction will lead to delays of departing flights.

They should also be ready to find fewer planes departing SFO at the most popular travel times and a smaller-than-planned bump in summer flights.

The new frustrations are the inevitable products of federally mandated safety work that will force SFO to close two of its four runways from May 17 through mid-September. SFO officials have been planning the work since 2008 and laid out the specifics Thursday.

The two runways that will remain open will have to handle arriving and departing flights, cutting into the airport’s capacity during one of the busiest travel seasons.

“Usually, what we see when we use two runways is that departing aircraft have to wait a little bit longer to take off,” said Doug Yakel, an airport spokesman. “If we see anything, we expect it to be five- to 15-minute delays at the gate.”

In trying to minimize delays, SFO will employ software that assigns each flight a departure time before it leaves the gate instead of requiring planes to queue up on the taxiways to wait to take off.

“Think of it like metering lights going on to one of the bridges,” said John Bergener, SFO’s planning manager. “Passengers won’t even get onto the plane until there is a slot for them.”

Middle of weekdays worst

While some delays are possible for arriving flights, Bergener expects them to be few. Departure delays are most likely during the airport’s busiest hours — between 10 a.m. and 1 p.m. on weekdays, he said.

When the skies are clear and the winds calm, SFO can handle up to 104 flights an hour: 54 arrivals and 50 departures. With the two runways closed, the airport will only be able to accommodate 45 planes landing and 40 taking off.

While half the airport’s runways will be closed, only 15 percent of capacity will be lost, Bergener said. That’s because the airport’s runways cross, requiring air traffic controllers to leave gaps to account for crossings. Using a single pair of runways eliminates those gaps.

Should fog or rain descend on the airport, however, typical bad-weather delays caused by SFO’s close-together parallel runways could slow departing and arriving flights for longer periods.

SFO has worked with the airlines to adjust their schedules, hoping to minimize delays. For many of the airlines, Yakel said, that means moving some flights out of the busiest periods of the day, which could make it tougher for people trying to book travel. Airlines had planned to increase the number of flights in and out of SFO by about 5 percent, he said, but will limit that growth to 2 percent because of the work.

Noise for neighbors

The closures could also cause more airplane noise for residents of communities near SFO, including San Bruno, South San Francisco and parts of Pacifica and Daly City, he said. Southern California-bound flights that now take off north before banking and heading south will take off toward the west during the construction.

The construction that’s causing the summer travel troubles is the creation of safety zones, required by the Federal Aviation Administration, at the end of each runway. Airports can either lengthen runways, which SFO already did on its other two, or install collapsible pavement designed to catch a plane’s landing gear and slow it to a stop.

“It’s the equivalent of a runaway-truck ramp,” Yakel said of this summer’s construction.

SFO regulars, accustomed to bad-weather delays, may wonder why the airport doesn’t simply extend its runways into San Francisco Bay, something that was proposed in the 1990s but quickly dropped in the face of those who opposed further filling of the bay.

“At this point in time, building another runway into the bay, even if it cleared environmental hurdles, would be too costly,” Yakel said.

Technology, including GPS-based systems that allow planes to travel closer together, especially during foggy and rainy conditions, is more likely to be the solution, he said.

Online extra: To see a video on the San Francisco airport work, go to

Michael Cabanatuan is a San Francisco Chronicle staff writer. E-mail: Twitter: @ctuan ___

Photo Credit: FAA-mandated runway fixes will lead to delays of departing flights at San Francisco International Airport this summer. San Francisco International Airport