SNOHOMISH — Bigger airplanes are flying into Harvey Field more often these days.

That’s one reason a new 20-year plan is in the works for the privately owned airfield’s future development. A new plan could include an option to extend the runway and reroute Airport Way to make room.

The airport handles more than 100,000 general-aviation flights annually. It is located just south of Snohomish but is part of the city’s urban growth area.

The Federal Aviation Administration says that regulators are interested in the length of the runway because Harvey Field is busier and is accommodating larger airplanes. The planning process will help the FAA determine whether the airport runway complies with regulations for the planes that use it most frequently.

But that’s not the only reason for updating the plan. Airports are required by the FAA to have up-to-date plans that anticipate future growth and ensure aircraft facilities are up to date. And it urges public involvement in that planning.

Harvey Field owner Kandace Harvey has hired Jviation, a Denver-based aviation development consultant, to oversee the planning process. A 27-member committee includes officials from Jviation, the FAA, the Washington State Department of Transportation Aviation division, Snohomish County, the city of Snohomish, local diking districts and neighbors of the airport.

An open house is scheduled for 6:30 p.m. April 1 at Harvey Field.

“We want the community to be involved,” said Harvey, whose family has run the airfield since 1944. “It’s very important to us.”

The airport planning process is expected to be complete in the spring of 2016.

The planning includes a look at businesses and how the airport affects the local economy. Harvey Field has 125 employees and is home to several businesses, including the Snohomish Flying Service, Skydive Snohomish, Aerial Balloon Co. and the Buzz Inn restaurant.

A group of pilots, meanwhile, is looking into FAA safety and design standards.

The FAA is providing $502,513 to cover about 90 percent of planning costs and preliminary engineering to evaluate the viability of different layouts. Harvey Field’s owner and the Washington State Department of Transportation are to split the remaining cost of about $55,835.

One trigger for a new plan was that Skydive Snohomish is routinely using a larger plane than before. The company’s Cessna 208B Caravan — a single-engine turboprop that carries up to 18 passengers — now makes more than 500 takeoffs and landings a year. That increased use by that bigger plane might indicate that Harvey Field’s runway needs to be extended, according to FAA guidelines.

The airport also has seen more twin-engine airplanes flying in recently, Harvey said.

Harvey Field has about a half-mile of paved runway. But pilots can’t safely use the southernmost 250 feet because they have to clear Airport Way. At the north end of the runway, 452 feet can’t be used because planes have to fly above trains on BNSF Railway tracks. That leaves 2,048 feet of usable runway.

Because the railway isn’t going to move, Harvey said, rerouting Airport Way to make more space for the runway will be considered.

Snohomish city manager Larry Bauman said one of the biggest questions is where money to move that Snohomish County-owned road would come from, if necessary. He thinks it is “highly likely” that the runway will need to be extended.

Because noise has long been a concern around the airport, the group is looking into that issue as part of the planning process, too. People living around avenues I and J in Snohomish are particularly sensitive to airplane noise, Harvey said.

Several years ago, Harvey Field put in place a voluntary noise reduction plan. It encourages pilots turn to the west as soon as safely possible after takeoff to reduce noise over the city.

Another concern is flooding. Harvey Field is in the Snohomish River Valley flood plain. Harvey said there hasn’t been any major flood damage at the airport since the dikes were built in 1995. But a group of experts and airport neighbors is looking into flooding and water issues as part of the airport planning process.

Owen Dennison, the city planning director and member of the airport committee, said the Federal Emergency Management Agency strictly limits what can be done with land in the flood plain around the airfield. People previously have expressed concern that developing the area around Harvey Field would increase flood risk.

The consultants recently submitted details about the property and a 20-year forecast for the airfield to the FAA for approval. The next step will be determining the airport’s future needs based on the forecast.

Amy Nile: 425-339-3192; anile@heraldnet.com. Twitter: @AmyNileReports.