PITTSFIELD — Fresh from an expansion, the Pittsfield Municipal Airport plans to rebuild its two aging runways.

That's needed to remain a safe and viable player in civil aviation, officials say.

But when dump trucks roll next year, planes for a time cannot.

The project would force the airport to close for nearly three months during the spring and summer of 2018.

At an estimated cost of $6 million, the runway and taxiway reconstruction would be small compared to the decade-long expansion that wrapped up in 2015 and cost more than $20 million.

"They need some TLC," David Nadeau of Stantec Consulting Services Inc. said of the airport's runways. He is the project's lead designer.

The effort still needs backing from the Federal Aviation Administration.

The city expects to file for 90 percent funding from the FAA by a May 1 deadline. The remainder of the cost would be split by the city and the state DOT. Their shares would be $300,000 each.

Pavement on the main runway, known as 8-26, is at least 25 years old. The surface of the smaller runway, dubbed 14-32, was laid more than three decades ago.

While both have been patched, they've outlived their expected use, Nadeau said.

"That only extends pavement life for so long," he said of partial repairs.

Nadeau briefed prospective bidders Tuesday at the airport, then led a convoy of pickup trucks filled with bidders on a tour of the work zone, as Brian Spencer, the airport's inspector, radioed out the group's location on an aviation channel.

As an airport vehicle rolled down the main runway, cracks and patches were evident.

Along with rebuilding runway surfaces to a depth of nearly a foot, the project will raise the level on parts of the smaller runway as much as two and a half feet to fix a line-of-sight problem that leaves pilots unable to see as far down the strip as the FAA requires.

Earlier, bidders listened as Nadeau walked them through the complex plan, laid out in stacks of thick documents. The work includes efforts to correct a list of lesser deficiencies and to shift to LED lighting for runway edges.

Nadeau said the new lighting system will save both on electricity and parts. Spencer says he replaces as many as 100 bulbs a year.

"We shouldn't have to touch an LED fixture," Spencer said in an interview after the tour.

GAINING USE

The project comes as the airport notches increased use, according to Gloria Bouillon, the facility's new manager. She said six new jets are based in Pittsfield.

"That's substantial growth compared to other general aviation airports," Bouillon said.

She expects that fact to help the airport's case for funding from the FAA.

But the airport's increased use will take a hit next year, when the proposed project would force its main runway to close for 85 calendar days, starting roughly May 1.

That will ground activities of the airport's fixed-base operator, Lyon Aviation.

A second phase to rebuild the outer edges of the smaller runway is scheduled to take 55 days. During that portion of the project, the main runway could be used.

But because the airport will be active, precautions will be needed.

"It will require your guys being on your radios," Nadeau told representatives of construction companies who attended Tuesday. About 12 people came to learn more about the project.

Nadeau said that to avoid lost business at the airport, the goal will be to "get the main runway up as soon as possible" for the benefit of Lyon Aviation.

"It impacts their revenue as well as the city's revenue," he said.

The winning bidder will face a $2,000-a-day penalty for not adhering to the timetable.

Bouillon said exact costs will be determined through the procurement process. Bids are due to the city by 2 p.m. April 19. The bid process is being managed by Colleen Hunter-Mullett, the city's purchasing agent.

Bouillon noted that rising materials costs could push the price tag.

"The cost of asphalt went up recently. We're hoping it stays around that area," she said.

Their airport's main runway is 5,791 feet long. The smaller strip measures 3,498 feet.

Reach staff writer Larry Parnass at 413-496-6214 or @larryparnass.