CITY HALL — The Airport Commission wants to explore incentives for pilots to fly more quietly in the wake of a successful test of a muffler that cut some airplane noise in half.

The device, manufactured by German company Golmozig, reduced the noise emitted by a Cessna 172 by over three decibels in some cases, and almost five in others, according to a study by City Hall.

It also shortened the duration of the sound — the total time that neighborhoods were exposed to the noise — by 43 and 56 percent, depending on where in the area one lives.

Although the tests have won praise from neighbors who are notoriously difficult to please when it comes to the Santa Monica Airport, actually getting aircraft owners to use the mufflers may present a challenge.

The devices cost roughly $5,000 to install, a prohibitive cost for some airplane owners and flight schools, which often keep Cessna 172s in their arsenal of practice planes.

In an effort to sweeten the deal for aircraft owners, commissioners got the ball rolling Monday on a recommendation to the City Council to pair the mufflers with an ongoing effort to raise landing fees at the airport.

Right now, only aircraft that fly into SMO, and are not based there, have to pay a fee of $2.07 per 1,000 pounds of weight that hits the tarmac. Officials initiated a process in July 2011 to study those fees and likely raise them in order to cover costs in the airport budget that historically has required a subsidy from the general fund, which pays for public safety, roads, libraries and other essential city services.

If that fee study reveals a need to raise rates and start charging pilots with planes based at SMO for their landings, something commissioners and the public have referenced often, City Hall may have leverage to encourage airplane owners to purchase the mufflers by providing breaks on landing fees.

Owners could then recoup their costs in mere months depending how many times they land aircraft, said John Fairweather, founder of Community Against Santa Monica Airport Traffic, or CASMAT.

The addition of the after-market muffler could also increase the overall value of the airplane, he suggested.

“This is an historic moment that we have here,” Fairweather said.

European airports have had similar programs in place for years, said Stelios Makrides, operations manager at SMO.

If a few decibels doesn’t sound like much to make a fuss about, think again.

Decibels are measured on a logarithmic scale, meaning that an increase of 10 decibels equates to a doubling in the level of noise. That means the muffler is, in some cases, cutting noise emitted by airplanes almost in half, as well as reducing the length of time that people hear it.

The results intrigued commissioners, who have seen other measures to reduce impacts of the airport on the community shot out of the sky by the very people they were meant to help.

The most recent example, a staff proposal to subsidize flight schools to fly to other airports to do training exercises that offend residents of Santa Monica and West L.A., met resistance from those who opposed the idea of lining aircraft owners’ pockets with tax dollars.

Deputy City Attorney Ivan Campbell was unable to give a full legal opinion without the say-so of the City Attorney’s Office, but said that the concept of a break in fees to encourage the use of the mufflers didn’t seem to violate federal or local policies.

“The city has wide latitude in constructing its fees,” he said.

Still, there is some concern that the proposal would discriminate against other kinds of planes for which no such muffler exists and would have no other option but to pay the landing fee.

Furthermore, the fees would have to see a fairly hefty increase and be applied to those who call Santa Monica home base or the “incentive” would be nearly meaningless — many of the small planes weigh roughly 2,000 pounds, meaning they would pay just over $4 to land at the current rates.

Officials will bring proposed landing fees back to the commission in February before they go to the City Council in April, said Martin Pastucha, director of Public Works.

ashley@smdp.com