New regulations that threatened the survival of a seaplane business that uses Richardson Bay were rejected by the Marin County Planning Commission Monday after a hearing of more than four hours.

About 250 people attended the meeting, filling the commission’s chambers to overflowing. Two commission members — Margaret Curran and John Eller — recused themselves because they live close to the area where the business, Seaplane Adventures, operates.

“This is an unusual hearing,” said Commissioner Pete Theran, who said he had never seen a standing-room-only audience for a commission meeting.

Responding to complaints from Strawberry homeowners and other residents about noise from the planes, the county’s planning division was recommending modification of Seaplane Adventures’ 1981 use permit.

The planning division recommended limiting the business to the same hours of operation and number of flights per day, six, as the adjacent Marin Heliport. The planning division also recommended limiting the capacity of the planes used by the business to eight passengers and prohibiting planes from entering the inlet between De Silva Island and Seminary Drive.

But Aaron Singer, who took over as owner of Seaplane Adventures in 2012, told the commission that such new regulations were out of the question.

“We’re a seasonal business,” Singer said. “We must be allowed to be successful during the summer if I’m to survive.”

Singer said being able to enter the inlet between De Silva Island and Seminary Drive was “100 percent necessary” for his planes to take off safely in the tricky winds that blow through the bay.

Dozens of members of the public spoke during the hearing and a majority of them expressed support for Seaplane Adventures and opposition to changes in its use permit.

“The seaplanes add such a great sense of joy and adventure and wonder to our lives,” said Tamara Cotton, who said she lives on Issaquah Dock in Sausalito.

Anne Woods of Tiburon said, “We actually love seeing those airplanes fly over. Every time we hear them we look up at them. For us the noise is not really noise.”

Woods, like a large number of the people who spoke against altering the use permit, had a connection with aviation.

“I’m a commercial seaplane pilot although I’m not affiliated with Singer’s operation,” Woods said.

A smaller number of speakers, however, had a much different take on the seaplane operation.

“At one time the seaplanes on west Richardson Bay were an entertaining community diversion,” said Stephen Fein of Strawberry Point. “But they have become a Frankenstein monster — 450 horsepower engines blasting away past our homes everyday.”

Bill Schneider, a spokesman for Strawberry Homeowners, said that when Seaplane Adventures obtained its initial use permit in 1953, “There were no homes on Strawberry Point, no Strawberry Shores apartments, no Strawberry Cove condominiums and no De Silva Island condominiums.”

“Today in 2017, Richardson Bay is no longer a commercial waterfront,” Schneider said. “It is a densely populated residential neighborhood with several thousand residents.”

In 1981, the planning commission modified the original 1953 use permit imposing a number of new conditions. These included: limiting noise levels to 86 decibels; limiting the number of commercial aircraft to four with only two permitted for simultaneous revenue producing purposes; banning approaches over Strawberry Point except when necessary for safety; requiring no-power approaches except when necessary for safety; banning use of the landing area by transient airplanes; and specifying that Richardson Bay can be used only for arrivals and departures.

Sightseeing flights have always constituted the bulk of Seaplane Adventures business, but flight training classes have also been offered in the past.

According to planning commission staff, Federal Aviation Administration records show that Seaplane Adventures averaged 48 flights per week in 2000. Since taking over the business, Singer has increased the number of flights. He told the commission Monday that during his busy summer season his planes might fly as many as 75 flights in a week. Singer said charter flights to Lake Tahoe are a popular new addition to his service.

The Strawberry homeowners’ group said rezoning of this area of Richardson Bay in 1965 made seaplane and helicopter uses there non-conforming. If that were the case, then the use would be allowed to continue at its historic level of intensity but could not be expanded.

The Strawberry homeowners contended that Seaplane Adventures had expanded its operations, however, by using larger commercial seaplanes. And the homeowners asserted Seaplane Adventures had violated its 1981 use permit by exceeding the 86-decibel level threshold by up to 2.5 decibels, operating more than two planes for revenue producing purposes and failing to adhere to no-power landing requirements.

Planning division staff reported that following a complaint about the business in 2015 it hired BridgeNet International, an aviation consulting firm, to monitor compliance with the use permit. BridgeNet found that Seaplane Adventures did at least twice exceed the 86-decibel level by up to 2.5 decibels.

But planner Jeremy Tejirian wrote in his report to the commission that given the ambient noise in the area this would be imperceptible to the human ear. Tejirian stated that BridgeNet concluded that Seaplane Adventures was being operated in substantial conformance with the 1981 use permit.

John Sharp, an attorney representing Seaplane Adventures, told the commission that federal law preempts the use permit’s conditions of approval, particularly as they concern noise restrictions.

Tejirian said if the county were to revoke Seaplane Adventures permit an amendment to the Countywide Plan would be required.

In the end, the commission threw up its hands.

“There is nothing we can do,” said Commissioner David Paoli. “Our hands are tied.”

Commissioner Christina Dresser said, “I don’t understand our jurisdiction over the matter.”

Instead of recommending to the Marin County Board of Supervisors that it impose new regulations on Seaplane Adventures, the commission voted unanimously to recommend eliminating three of the current restrictions, including the 86-decibel limit, because they conflict with federal law.

Tejirian noted that neighbors concerned about noise could still appeal to the Federal Aviation Administration, which does have jurisdiction.