An Elite Airways Bombardier CRJ-900 jetliner at the Portland International Jetport. Photo courtesy of Elite Airways

The Portland International Jetport started a monthlong series of overnight closures this week to continue repaving its main runway, a project that has disrupted normal operations for about a month and caused some incoming flights to be turned away in low-visibility conditions.

Flights are prohibited from landing at the airport from 10:30 p.m. to 5:45 a.m. until June 13, the jetport said this week.

The overnight closures were planned more than a year ago as part of a $13.7 million rehabilitation of the jetport’s main runway. Closing the airport should not impact normal travel but could pose issues if a late flight is delayed, Airport Director Paul Bradbury said.

A month into the rehabilitation, multiple flights have been forced to abandon their landing in Portland and fly to another city because of poor weather conditions on the secondary north-south runway.

Bradbury said he did not have immediate access to the total number of turned-away flights over the last month. As of 5 p.m. Tuesday, the website FlightAware was reporting 17 flight cancellations at the jetport over the previous 24 hours, but it didn’t specify how many of those were related to the runway work.

If there is rain or low visibility in Portland when a plane tries to land, there is a likelihood the flight will be affected, Bradbury said. The shorter, secondary runway makes it harder for long, heavy jets to land. It’s also not equipped with the precision instrumentation that can guide flights even when conditions are poor.

Some flights have had to unexpectedly break off their approach to Portland and reroute to a different airport until conditions improved, Bradbury said. Airlines were aware of likely issues that would crop up as the jetport replaced its runway, he added.

“We knew there were going to be impacts – this was the optimal planning we did with aircraft partners to minimize them,” Bradbury said. “We apologize to the members of our traveling public as we work on this.”

A pilot may be intending to land until the plane arrives in Portland and setting down is determined to be unsafe, Bradbury said.

“If the conditions in that moment are not appropriate, the decision has to be made to go to an alternate airport,” he said.

Herb Semple, 70, was returning to Portland from San Diego via Detroit last week when his Delta Airlines flight was diverted. The flight was supposed to land at 10:30 p.m., but as it came into the Portland area, Semple noticed a thick fog over the coast.

The plane approached the runway, leveled out, then climbed again, Semple said. Fifteen minutes later, passengers were informed that they were now headed to Bradley International Airport, near Hartford, Connecticut.

“We had to get off the plane. They said, ‘Things are socked in with very dense fog. We can’t fly back; we can’t land,’ ” Semple said.

A flight to Portland was scheduled at 11 a.m. the next day, he said, but because Delta wouldn’t provide hotel rooms for a weather delay, passengers would have to spend the night in the airport. Semple found a car rental agency that opened at 4 a.m. and decided to drive back to Portland instead.

He later received an apology from Delta, some frequent flyer miles and a note saying the airline would consider reimbursing lodging or travel expenses.

Fellow passengers seemed to accept the unexpected detour, Semple added.

“People were taking it in stride. Fog is fog – you have to abide by the airline in terms of their judgment for safety,” he said. “I’ve been flying a lot lately; I prefer this stuff to lost luggage.”

The overnight closures are not expected to add significantly to the runway-related disruptions.

Flights typically land in Portland up until midnight or even later, but airlines have adjusted schedules around the closure, Bradbury said. Airlines preferred overnight closures to a shorter, round-the-clock closure, as did the jetport’s noise advisory committee, he said.

Construction is on schedule, Bradbury said, and the main runway is expected to reopen on June 13.