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Sun, Aug. 09

Data indicates little natural quiet in park
In initial findings aircraft noise is well above goal

Preliminary sound modeling with data gleaned last summer shows that the park meets the definition for natural quiet only 8 percent of the time.

According to Ken McMullen, overflights and natural sound scapes program manager at Grand Canyon, data was collected over a 12-hour period on Aug. 8, "a peak day," he said.

Researchers collected ambient sound data in four vegetation types as a baseline for the modeling. They also tracked and categorized aircraft operations that day ­ in all, more than 1,200 commercial jets, nearly 200 general aviation (military, private and corporate charter) and more than 600 tour-related flights passed over the Canyon.

"We did several kinds of measurements and looked at how much of the park was affected by air operations on this day," McMullen said. "Its purpose is to define where aircraft noise becomes audible to a person sitting on the rim actively seeking natural quiet, or just solitude."

If the study only included air tours and related activity, the park would fit within the standard. On the day that researchers measured, air tour operations disrupted natural quiet more than three hours per day in 46 percent of the park. But a 2002 lawsuit required that all aircraft be counted. Everything but air tour activity impacted 99 percent of the park more than half the time.

"When you consider that noise, the park does not meet the definition for substantial restoration of natural quiet," said Grand Canyon National Park Superintendent Joe Alston. "If you take the noise generated by just the air tours, we're already close to not meeting the standard."

Simply re-routing that traffic around the Canyon isn't a viable option.

"Someone said it would be easier to move the Canyon, so there isn't much of a variable to work with," Alston said.

Winter data is being collected now, with findings expected in May. Though winter ambient levels will be lower, so is the number of flights so officials anticipate similar results.

"We think these values will change and drop. With fewer flights there will be less noise generated but with the lower ambient level, it could sort of counterbalance that," McMullen said.

While actual alternatives haven't been drafted, officials and the working group have identified the management tools they will use to develop options. These include flight-free zones, flight routes, altitude, curfews, zoning, seasonal restrictions, quiet technology and the number of daily operations.

The data was available at a series of open house events hosted by Federal Aviation Administration and Park Service officials last week as they move through a 90-day public comment period that ends on April 27.

According to Mary Killeen, Chief, Office of Planning and Compliance, the agencies are looking for comment in three main areas ­ ideas, comments and suggestions on potential alternatives to restore natural quiet; suggestions and ideas related to aircraft; and input on preservation of natural and cultural resources.

"We're getting ideas from the public, and we will take those ideas back to the working group," said McMullen.

The two agencies are working jointly to meet a federal mandate to achieve natural quiet ­ defined as freedom from aircraft noise in at least half the park for at least 75 percent of the time. Under the National Parks Overflight Act (Public Law 100-91), passed in 1987, the deadline to meet that goal is 2008.

Since the law was signed, it's been shaped by supplemental law, undergoing what Alston terms an evolution.

"If you think about it, there's already been a lot of public process that's gone into this, a lot of thought that's gone into it," he said. "Part of it is legislation, part of it was precipitated by a serious air crash, there have been some lawsuits that have been involved. Like all public policy there are a lot of things that go into it and this has had its fair share."

The process took a big step forward about a year and a half ago, when NPS and the FAA announced that they had come to agreement, with the aid of mediation, on which noise model to use.

Leading in the mediation process is Lucy Moore, a mediation consultant contracted by the U.S. Institute for Environmental Policy Resolution, a government agency operated by the Morris K. Udall Foundation in Tucson. That is continuing with a 30-member working group made up of representatives for various stakeholder groups. These include members of the Navajo, Hopi, Havasupai and Hualapai tribes; conservation groups; hiking and boating groups; other state and federal agencies; and the air tour industry.

"They're attempting to reach ­ I wouldn't say a consensus, but they're at least attempting to reach some alternatives that they can consider a range of options," said Killeen. "Then we'll bring that to the public again."

That's expected by the summer of 2007, with a final record of decision by early 2008. Because of interest from the Arizona congressional delegation and aviation leaders like Elling Halvorson, Alston said the process has come further at Grand Canyon than for 93 other NPS units subject to air tour activity.

"These other 93 parks out there, they're struggling with how they do it, and most of them don't have the resources that the Grand Canyon does," he said. "Certainly how we look at the issues and identify the issues and come up with solutions, that's going to be looked at."

For everything you could possibly want to know about the Overflight Rule, its history and actions surrounding it, visit Send comments to Docket Management System, Doc. No. FAA-2005-23402, U.S. Department of Transportation, Room Plaza 401, 400 Seventh St. SW, Washington, D.C., 20590-0001 or submit online at

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