LONGMONT — A lawsuit dated Tuesday accuses Mile-Hi Skydiving of endangering health and safety with its airplane noise, and asks for financial damages, tighter business hours and a new flight pattern.

“Plaintiffs have lost sleep, endured stress and anxiety and had their lives disrupted due to the excessive noise harms,” attorney Randall Weiner wrote for the activist group Citizens For Quiet Skies, which brought the lawsuit. The suit claims Quiet Skies members have been injured “physically and mentally” by the sound of the skydiving planes and have seen their home values drop.

Weiner also singled out the company’s most-recognized plane, its DeHavilland Twin Otter, as having a “particulary disruptive, far-reaching” drone, and charged that all the planes could be heard beyond the “flight box” that Mile Hi was required to stick to., even with windows closed.

Mile-Hi owner Frank Casares declined to comment. The skydiving company has operated out of Vance Brand Municipal Airport since 1995.

Quiet Skies has been raising money for the suit since November, founder Kimberly Gibbs said, and is still collecting funds. She said the group is employing a noise expert for the case and may name additional defendants, though she did not say whether that would include the city, the airport or the Federal Aviation Administration.

“Lawsuits are hard. We may not win,” Gibbs said. “Win or lose, as far as the lawsuit is concerned, I consider this a great moral victory to have even made it to this point.”

Several of the members live outside Longmont, including Gibbs, a Gunbarrel resident. A release by the group on Monday claimed Erie residents had been affected as well; that was put into the final draft by mistake, Gibbs said.

Discussions between the skydiving company, the two-year-old activist group and the city have produced a few colorful moments — in 2012, as a joke, Casares sent the group bumper stickers that read “I Love Airplane Noise.” — but little resolution. The company has maintained that it’s operating legally, while city officials have said that FAA regulations offer them little leeway to make changes. Gibbs, in return, has disputed that, arguing that “reasonable regulation” is not impossible.

A Tuesday evening news conference on the lawsuit was attended by about 20 people, including City Council candidates Ron Gallegos and Jeff Moore.

Gallegos, who served on the council from 1995 to 1999, said he never wanted to see residential neighborhoods get as close to the airport as they did. Now the city has to deal with the impact, he said.

“A lot of us didn’t want to change the zoning (of nearby areas) from light industrial to residential, because we knew what would happen,” Gallegos said. “I hate to be the one to say this, but I told you so.”

Scott Rochat can be reached at 303-684-5220 or srochat@times-call.com.