A master plan for Belfast Municipal Airport is headed to the City Council on May 15 for final approval amid objections from some neighbors. The document, which must be updated for the city to be eligible for Federal Aviation Administration funding, describes improvements or additions to the airport that might be needed decades from now.

Any projects for which the city hopes to receive funding from the FAA must appear on the document. The current master plan dates to 1999. The proposed update includes some projects that city officials say are not needed now, but shouldn't be ruled out in the long term.

At least one of these — an extension of the runway from 4,000 feet to 4,710 feet — has grabbed the attention of neighbors, who have asked to have it removed from the list.

Airport Manager Thomas Kittredge said the conversation about extending the runway started with a request from athenahealth, a frequent user of the airport. The company makes almost daily flights with its Pilatus PC-12 turboprop plane, but had hoped to use a larger Bombadier Challenger 300 jet, which would need a longer runway for takeoff. The company reportedly sold that jet as part of a restructuring earlier this year.

Kittredge said athenahealth is the only airport user to ask about extending the runway.

"I think anything with the runway extension is in deep freeze for the foreseeable future," he said.

The FAA funds 90 percent of capital improvements and certain safety measures at the airport. The state pays another 5 percent, leaving just 5 percent that must be covered by the city.

Belfast gets $150,000 each year for capital projects. For more expensive projects, the city can apply to get future year's funding in advance, which comes out of funding for municipalities that aren't doing projects in a given year.

The City Council recently approved spending $200,000 from reserve accounts to fund its portion of a new $4 million parallel taxiway. That project could begin later this year and is expected to open July 2019. Additionally, the city is about to go out to bid for a new self-service fuel farm (fueling station) with 100 Low Lead and Jet A fuels.

Today there are 14 aircraft based in Belfast. There were 2,193 operations — an aircraft taking off or landing — from March 2017 to February 2018, based on a system that uses radio transmissions to estimate traffic volume. The previous year there were 3,328 operations.

Athenahealth is probably the most frequent flyer, Kittredge said. The company's plane made about 500 operations last year, or roughly one round-trip every business day.

Any runway extension would happen on city land, Kittredge said; however, a longer runway would extend the areas at either end of the runway where trees would be cut to clear the approaches for aircraft.

Kittredge said the city has no plans to extend the runway, but he recommended keeping the door open in the event that something changed.

Several neighbors of the airport speaking to the City Council on May 1 argued that putting it in the plan made it more likely to happen, or at least a possibility.

If that happened, Kittredge said, it would have to come from the city. The FAA likes to make sure airports are giving priority to safety improvements, he said, but doesn't weigh in on non-safety-related projects like expanding an airport's capacity.

The council was scheduled to take a final decision on May 1 but postponed its vote after learning that a letter sent to abutting property owners had not arrived 30 days before the meeting as was intended.

The council will take up the question again at 7 p.m. Tuesday, May 15, at City Hall, 131 Church St.